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Keywords:

  • Aversions;
  • cravings;
  • maternal diet;
  • nausea and vomiting in pregnancy

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information

Objective

To investigate primarily the dietary intake, as well as demographics and selected lifestyle factors, of women experiencing nausea and vomiting in pregnancy, nausea only, or women who are symptom free.

Design

Prospective cohort study.

Setting

The Norwegian Mother and Child Cohort Study, a population-based pregnancy cohort.

Sample

Analyses were based on 51 675 Norwegian pregnancies.

Methods

Dietary intake was assessed by a self-reported food frequency questionnaire answered in the first trimester of pregnancy, as were data regarding nausea and vomiting. Chi-squared tests, one-way analysis of variance, and multiple linear regression were used.

Main outcome measures

Nausea and vomiting in pregnancy (NVP), gestational weight gain (GWG), and dietary intake.

Results

We found that 17 070 (33%) women experienced NVP, 20 371 (39%) experienced only nausea, and 14 234 (28%) were symptom free. Women with NVP were younger and heavier at pregnancy onset, with the lowest GWG and highest energy intake during pregnancy, primarily from carbohydrates and added sugars, compared with the other groups (P < 0.001). In multiple linear regression analysis of GWG and group adjusted for body mass index (BMI), gestational length, smoking during pregnancy, and energy intake, a significant interaction was found between BMI and group (P < 0.001). A significant effect of group (P < 0.001) was found in all BMI strata, except among underweight women (P = 0.65).

Conclusions

Our study suggests that women with NVP are characterised by high intakes of carbohydrates and added sugar, primarily from sugar-containing soft drinks. Whether higher intakes of carbohydrates are a response aimed to alleviate symptoms, or are actually provoking the condition, is not known.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information

Nausea and vomiting during pregnancy (NVP) or nausea alone (NP) are often classified as mild (only nausea), moderate (nausea and vomiting), or severe. In the latter and rarer case, termed hyperemesis gravidarum (HG), the extent of vomiting is so profound that maternal weight loss, electrolyte imbalance, and dehydration requiring hospitalisation may result.[1-3] Most studies report approximately 80% of women experience NVP, although no clear underlying mechanism has been demonstrated.[1-4] Symptoms typically begin in the first trimester, around gestational weeks 5–8, usually peaking around gestational week 9, and subsiding by around gestational week 12.[5, 6] Previous studies describe women experiencing NVP as young,[7, 8] with a low education level,[9] multiparous,[10, 11] and as smokers,[12] although the findings are inconsistent.[13, 14]

During a normal pregnancy, women typically crave or are repulsed by certain foods. Earlier studies mention sweet foods (e.g. sweets, chocolate, and biscuits), fruits and fruit juices, milk and other dairy products as commonly being craved.[15, 16] The most commonly reported aversions were for drinks containing caffeine, fatty/greasy foods, spicy or highly flavoured foods, and high protein foods (particularly meat).[16, 17]

In women experiencing NVP the typical gestational diet is further affected, although only a few studies have addressed this. One study found that women who experienced NVP had increased food aversions and a decreased appetite compared with those without NVP symptoms.[18] A recent study comparing NVP women with a symptom-free group found that NVP women had a higher carbohydrate intake, a lower protein intake, and a lower energy intake.[19]

The properties of the gestational diet have become increasingly associated with consequences for the future health of the offspring, especially in relation to non-communicable chronic diseases.[20, 21] The aim of this study, using data from a large population-based cohort, was primarily to assess dietary intake, as well as demographic profile and lifestyle factors, in pregnant women divided into three groups: those experiencing NVP, those experiencing nausea alone, and those without symptoms of NVP or nausea.

Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information

The Norwegian Mother and Child Cohort Study

The Norwegian Mother and Child Cohort Study (MoBa) is a national pregnancy cohort that included 108 000 pregnancies from 1999 to 2008. Participants were recruited from all over Norway, and 38.5% of the invited women consented to participate. The women were asked to provide biological samples and to answer three questionnaires during pregnancy. Follow-up questionnaires were delivered postpartum at regular intervals and linked to national health registries. Pregnancy and birth records from the Medical Birth Registry of Norway (MBRN) are linked to the MoBa cohort.[22] MoBa was initiated by, and maintained at, the Norwegian Institute of Public Health.[23]

Questionnaires and variables

The data included in this study are collected primarily from the two questionnaires answered in gestational weeks 15 (Q1) and 18–22 (Q2), respectively. Data regarding maternal age, parity, and gestational length were obtained from the MBRN. Parity from the MBRN and previous pregnancy questions from Q1 were combined in order to minimise missing values. Data from questionnaire three (Q3) was used to sort cases diagnosed as HG, defined as prolonged nausea and vomiting during pregnancy that required hospitalisation before week 25 of gestation. We also included one question, answered 6 months postpartum (from questionnaire four, Q4) on maternal weight at the end of pregnancy. The present study used the quality-assured data files released for research in 2009 (version four).

Q1 was a general questionnaire covering details regarding health, lifestyle, demographic information, as well as early reports of general nausea and/or vomiting. From Q1 we used maternal height (cm), weight at the start of pregnancy (kg), previous pregnancies, previous experiences of NVP (yes/no), education (seven categories, collapsed into: ≤12 years; 13–16 years; ≥17 years of education; other or missing), marital status (six categories, collapsed into: married; single or widow; cohabiting; other or missing), annual maternal income (seven categories, collapsed into: no income; <300 000 NOK [Norwegian kroner; 1 NOK ~0.12 GBP]; ≥300 000 NOK; missing), and smoking before and during pregnancy (no; sometimes; or daily). Maternal body mass index (BMI) was calculated as weight at the start of pregnancy divided by height[2] (kg/m2).

Q2 included a semi-quantitative food frequency questionnaire (FFQ) designed to capture dietary habits and use of dietary supplements during the first 4–5 months of pregnancy.[24] Nutrient calculations were performed by FoodCalc and the Norwegian food composition table.[25, 26] The FFQ has been thoroughly validated with regard to nutrients, foods, and use of dietary supplements.[27]

Version two of Q2, unlike version one, included detailed questions regarding nausea and vomiting, in addition to containing an FFQ, and it is the women answering version two that were included in this study. The nausea and vomiting questions probed the incidence of nausea or vomiting during pregnancy (yes/no), the gestational week of onset and cessation, and whether women were still experiencing nausea and/or vomiting at the time of answering. Questions concerning nausea were addressed separately from vomiting. Women answering ‘yes’ to nausea were asked whether this had created any increase or decrease in their consumption of food items (more/less), as compared with pre-pregnancy. They were also asked whether they had begun to eat or drink any specific foods as a consequence of the pregnancy (yes/no). If an answer of ‘yes’ had been recorded, a follow-up open question asked women to note which new food items they had begun to consume.

Prior to calculating the duration of either nausea or vomiting from the variables stating the gestational weeks of onset and cessation of these symptoms, some recoding of data was required. Those with missing values for the week of onset of nausea or vomiting, yet indicating that they were ‘still nauseous/still vomiting’ at the time of answering, were given the value ‘week 5’ (the most common week for the onset of symptoms; n = 2469 women).[5, 6] Those reporting a cessation of nausea or vomiting outside of a 26–week range (n = 42), or with missing values for this variable (n = 9933), yet indicating that they were ‘still nauseous/vomiting’ at the time of answering, were assigned the gestational week when the questionnaire was answered. The duration of nausea or vomiting was calculated by subtracting the week of onset from the week of cessation. Those with a zero difference, yet reporting episodes of nausea or vomiting, were given a duration of 0.5 weeks (n = 349). Women who had answered ‘no’ to experiencing either nausea or vomiting, yet had a calculated duration for ‘number of weeks nausea/vomiting’ ≤26 weeks, had ‘no’ recoded to ‘yes’.

Women who had a missing answer (n = 186) or a ‘no’ (n = 110) as to whether they had begun to eat or drink certain foods during pregnancy, yet proceeded to enter a food/drink item in the field provided, had that answer recoded into a ‘yes’. The answers to the open question concerning new food items consumed were categorised into 21 food groups (milk/milk products, bread/cereals, biscuits/buns/cakes, fat, meats, fish, egg, vegetables, fruit, chocolate, sweets, coffee, teas, juice, carbonated drinks, water, alcohol, spreads, miscellaneous, pica, general food types), in addition to eight general food categories (foods reportedly helping to reduce nausea, helping digestion, containing probiotics, rich in protein, rich in fat, rich in sugar, containing artificial sweeteners, rich in sour/salty taste). A complete catalogue of the categorised foods is available in Appendix S1. All mention of ‘salty snacks’ includes salted peanuts, potato chips, popcorn, and pretzel sticks. All mention of ‘fresh meat’ includes beef, pork, lamb, game, and poultry. All mention of ‘processed meat’ includes meat and poultry processed spreads, minced meat, meat balls or hamburger patties, sausages, and bacon. All mention of ‘fresh fish’ includes tuna, mackerel, halibut, cod, pike, and salmon. All mention of ‘processed fish’ includes fish cakes, crumbed fish, fish fingers, fish pâtés, caviar, fish spreads, and tinned sardines.

Gestational weight gain (GWG) was calculated as weight at the end of pregnancy (from Q4) minus maternal weight at the start of pregnancy (from Q1). Q4, answered postpartum, had a lower response rate compared with Q1 or Q2. Owing to this, there are data missing for 8305 women (16% of sample) regarding GWG. In the analysis of GWG, only women with values between−30 kg and +50 kg were included.

Study sample

The entire MoBa cohort consists of 108 842 children. The present study included women with singleton births answering Q1 and version two of Q2 (Figure 1). Further exclusions were made for women failing to answer questions relating to episodes of nausea and/or vomiting, or reporting nausea or vomiting lasting for longer than 26 weeks. Reports of both nausea and NVP were cross-checked from answers provided in both Q1 and Q2, with exclusions made for inconsistent or contradictory answers between the two questionnaires, or with contradictory answers such as simultaneously answering both ‘yes’ and ‘no’ to nausea and/or vomiting (n = 15 791). Those women reporting only vomiting (n = 346), those hospitalised for HG (n = 867), and women with an energy intake outside 4500–20 000 kJ were also excluded.[28] Women enrolled in MoBa more than once for additional pregnancies had all but their first participation excluded (n = 9699). Finally, women with a gestational length outside weeks 28–42 (n = 964), women without a successful pregnancy (i.e. non-living births; n = 166), and those with missing weight and height data at the start of pregnancy were also excluded. In total, 51 675 women were included in the final study sample.

image

Figure 1. Flow chart showing the pathway to the final study sample from the Mother and Child Cohort Study (MoBa).

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Statistical analyses

The final study sample was divided into three groups, reflecting answers concerning incidences of nausea and vomiting: symptom free (SF); only nausea (NP); or both nausea and vomiting (NVP).

Results are presented as means (SDs) or frequencies (%). One-way analysis of variance (anova) was used to compare the three groups (SF, NP, and NVP), and pairwise comparisons were performed using Bonferroni's correction. We present the P value from the comparison of the three groups, and, if significant, we indicate in the tables which of the pairwise comparisons were significant. Chi-squared tests were performed for categorical variables. As a pure comparison of the three groups is the main aim of the paper, adjustments for covariates were in general not performed; however, multiple linear regression analysis was performed for GWG to adjust for BMI (continuous), gestational length (continuous), smoking during pregnancy (yes/no), energy intake (continuous), and group (SF, NP, or NVP). These results are presented as crude and adjusted marginal means with 95% confidence intervals. As there was a significant interaction between group and BMI, we tested the difference between groups in analyses stratified by BMI: <18.5 kg/m2 (underweight); 18.5–24.9 kg/m2 (normal); 25–29.9 kg/m2 (overweight); and >30 kg/m2 (obese).[29] A significance level of 0.05 was used. All analyses were performed using spss 20.0 (SPSS, Inc., Chicago, IL, USA).

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information

Maternal characteristics

In this study sample, 28% reported no symptoms of nausea or vomiting in pregnancy (SF group), 39% had experienced nausea alone (NP group), and 33% reported both nausea and vomiting (NVP group). The NVP group had the lowest mean maternal age at delivery, height, and GWG, as well as the highest mean weight and BMI at the start of pregnancy (Table 1). The NVP group also had the lowest proportion with a BMI of 18.5–24.9 kg/m2 (normal weight), and the shortest duration of education. Of women who had experienced NVP in an earlier pregnancy, 63% reported NVP in this pregnancy.

Table 1. Maternal demographics and selected lifestyle factors for the three groups
 Total n = 51 675Symptom free (SF) n = 14 234Nausea (NP) n = 20 371Nausea and vomiting (NVP) n = 17 070 P a
n Mean (SD)Mean (SD)Mean (SD)
Maternal age at delivery (years)51 67530.3 (4.5)b30.8 (4.4)29.2 (4.6)<0.001ghi
Height of mother (cm)51 675168.2 (5.9)168.4 (5.8)167.8 (6.1)<0.001ghi
Maternal weight at pregnancy start (kg)51 67567.5 (12.3)67.8 (12.3)68.6 (13.7)<0.001hi
BMI at pregnancy start (kg/m²)51 67523.9 (4.1)23.9 (4.1)24.3 (4.6)<0.001hi
Gestational weight gain (kg)43 37015.1 (5.7)15.1 (5.8)14.4 (6.4)<0.001hi
Missing8305194828993458 
  n (%)n (%)n (%) 
  1. a

    One-way anova for continuous variables and chi-squared test for categorical variables.

  2. b

    Mean (SD).

  3. c

    Frequency (%).

  4. d

    Variables from MoBa and MBRN defined parity.

  5. e

    Not included in percentage distribution.

  6. f

    Norwegian kroner, 1 NOK ~0.12 GBP.

  7. g

    Pairwise comparison: SF versus NP significant.

  8. h

    Pairwise comparison: SF versus NVP significant.

  9. i

    Pairwise comparison: NP versus NVP significant.

BMI at pregnancy start (kg/m²)
<18.51546430 (3.0)c551 (2.7)565 (3.3) 
18.5–24.934 0979607 (67.5)13 818 (67.8)10 672 (62.5)<0.001
25–29.911 1943012 (21.2)4275 (21.0)3907 (22.9) 
≥3048381185 (8.3)1727 (8.5)1926 (11.3) 
Having previously experienced NVP d
Yes9163556 (8.8)2688 (23.7)5919 (63.4)<0.001
No17 8155738 (91.1)8667 (76.3)3410 (36.5) 
Parity d
027 4928947 (62.9)9475 (46.5)9070 (53.2) 
115 6153378 (23.7)6898 (33.9)5339 (31.3)<0.001
≥285411900 (13.4)3990 (19.6)2651 (15.5) 
Missinge27    
Maternal education (years)
≤1215 4904200 (30.2)5535 (27.7)5755 (34.5) 
13–1621 7715948 (42.8)8814 (44.1)7009 (41.2)<0.001
≥1713 3373762 (27.1)5640 (28.2)3935 (23.6) 
Other/missinge1077    
Marital status
Married23 8786029 (43.0)10 026 (49.9)7823 (46.6) 
Single/widow1162349 (2.5)373 (1.9)440 (2.6)<0.001
Cohabiting25 8687634 (54.5)9709 (48.3)8525 (50.8) 
Other/missinge767    
Annual maternal income
No income1093226 (1.6)356 (1.8)511 (3.1) 
<300 000 NOKf30 2237858 (56.9)11 632 (58.8)10 733 (64.9)<0.001
≥300 000 NOKf18 7945729 (41.4)7768 (39.3)5297 (32.0) 
Missinge1565    
Smoking 3 months prior to pregnancy
No36 8449586 (67.9)14 833 (73.4)12 425 (73.5) 
Occasionally53041546 (11.0)2117 (10.5)1641 (9.7)<0.001
Daily91022983 (21.1)3269 (16.2)2850 (16.9) 
Missinge425    
Smoking during pregnancy
No47 44712 688 (89.8)18 993 (93.8)15 766 (93.0) 
Occasionally1328503 (3.6)449 (2.2)376 (2.2)<0.001
Daily2554946 (6.7)805 (4.0)803 (4.7) 
Missinge346    

The SF group had the highest proportion of primiparous women, cohabitating women, and women in the highest income group. Furthermore, the SF group had more occasional or daily smokers, both before and during pregnancy.

The NP group had the highest mean age, highest proportion of multiparous women, and the largest proportion with ≥13 years of education. The final study sample consisted of 51 675 women, and a comparison of demographics for these women with women excluded from the present study from the entire MoBa sample (n = 41 195) showed discrepancies regarding maternal age at delivery, education, marital status, maternal income, and parity (Table S1).

In multiple linear regression analysis of GWG and group, adjusted for BMI, gestational length, smoking during pregnancy, and energy intake, a significant interaction was found between BMI and group (P < 0.001). A significant effect of group (P < 0.001) was found in all BMI strata, except among underweight women (P = 0.65), and the adjusted GWG marginal means were lowest in the NVP group (Table 2). Obese women had markedly lower GWG values in all groups.

Table 2. Multiple regression analysis of gestational weight gain (kg), stratified by BMI; n = 43 100
BMI strata (kg/m²)Symptom free (SF)Nausea (NP)Nausea and vomiting (NVP) P b
CrudeAdjustedaCrudeAdjustedaCrudeAdjusteda
  1. a

    Adjusted for gestational length, smoking during pregnancy, and energy intake.

  2. b

    P value for group, adjusted analysis.

  3. c

    Marginal means (95% CIs).

<18.5 (n = 1226)15.0 (14.5–15.5)c15.4 (14.8–15.9)15.2 (14.7–15.6)15.6 (15.0–16.1)15.0 (14.5–15.5)15.4 (14.8–15.9)0.65
18.5–24.9 (n = 28 659)15.4 (15.3–15.5)15.9 (15.8–16.1)15.4 (15.3–15.5)15.9 (15.7–16.0)15.1 (15.0–15.2)15.5 (15.4–15.7)<0.001
25–29.9 (n = 9348)15.3 (15.1–15.5)15.8 (15.6–16.0)15.3 (15.0–15.5)15.8 (15.6–16.0)14.3 (14.0–14.5)14.8 (14.5–15.0)<0.001
>30.0 (n = 3867)12.1 (11.7–12.6)12.7 (12.3–13.1)12.0 (11.6–12.4)12.5 (12.2–12.8)10.3 (9.8–10.7)10.8 (10.5–11.1)<0.001

Nausea and vomiting

The NVP group had a significantly longer duration of nausea than the NP group (mean [SD]) 9.6 (3.9) weeks versus 7.4 (3.2) weeks, P < 0.001. More women in the NP group were affected by a shorter period of nausea (≤8 weeks) than the NVP group (Figure 2).

image

Figure 2. Frequency distribution showing duration of nausea for women with nausea only (NP; n = 20 233), and for women with nausea and vomiting during pregnancy (NVP; n = 16 981).

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In response to whether nausea caused women to eat more or less, 59% responded that they ate less. A significantly higher proportion in the NVP group ate less (68%) than in the NP group (51%, P < 0.001).

In the NVP group, 65% of the women experienced vomiting for 8 weeks or less, with a peak between weeks 6 and 8 (28%), whereas 33% experienced vomiting between weeks 9 and 17.

Dietary intake

The NVP group had the highest total mean energy intake (9830 kJ), and the SF group had the lowest (9539 kJ; Table 3). Mean intakes of all macronutrients were highest in the NVP group, except for monounsaturated fat and fibre, where the NP group had the highest mean intakes. Significant differences in energy percentage (E%) were found between the three groups for all macronutrients (P < 0.001), except for polyunsaturated fat (P = 0.23). In pairwise comparisons all three groups were significantly different from each other for all macronutrients (P < 0.001), except for added sugar and monounsaturated fat, for which the SF and NP groups both significantly differed from the NVP group (P < 0.001), and fibre, for which the NP group significantly differed from both the SF and NVP groups (P < 0.001). Mean intakes of the micronutrients retinol, beta carotene, folate, and vitamin C were highest in the NVP group (Table 3). Mean intakes of niacin, magnesium, and calcium were highest in the NP group; all other micronutrients had equally high mean values in the NP and NVP groups. Significant differences in the levels of micronutrient intake per 10 MJ energy intake were found between the three groups for all micronutrients (P < 0.001), except for retinol (P = 0.51), folate (P = 0.88), and vitamin D (P = 0.32). In pairwise comparisons, all three groups were significantly different from each other for three macronutrients only (P < 0.001). The intake of riboflavin, thiamine, iron, magnesium, and calcium in the SF and NP groups significantly differed from that in the NVP group (P < 0.001), whereas the intake of vitamin E in the SF and NVP groups significantly differed from that in the NP group (P < 0.001). Vitamin B12 intake in the SF group significantly differed from that in the NP and NVP groups (P < 0.001), and beta carotene intake in the SF group significantly differed from the NVP group (P < 0.001).

Table 3. Total daily intake, energy percentage (E%), or amount per 10 MJ consumed (/10 MJ) for macro- and micronutrients from the food frequency questionnaire, n = 51 675
 Symptom free (SF)Nausea (NP)Nausea and vomiting (NVP)E% Pa
IntakeE%IntakeE%IntakeE%
Energy (kJ)9539.8 (2527.8)b 9706.2 (2489.0) 9830.7 (2722.1) -
Carbohydrates (g)301.9 (90.6)53.5 (4.7)308.3 (88.6)53.8 (4.7)315.4 (98.0)54.3 (5.0)<0.001cde
Added sugar (g)59.8 (37.2)10.4 (4.8)61.0 (36.1)10.4 (4.7)65.5 (42.7)11.0 (5.4)<0.001de
Protein (g)86.3 (20.9)15.6 (2.1)87.2 (20.7)15.5 (2.1)87.3 (22.5)15.3 (2.2)<0.001cde
Fat (g)79.0 (23.7)30.7 (4.5)80.1 (23.7)30.6 (4.5)80.2 (25.3)30.2 (4.6)<0.001cde
Saturated fat (g)30.6 (9.8)11.9 (2.1)30.8 (9.8)11.8 (2.0)30.9 (10.4)11.6 (2.1)<0.001cde
Monounsaturated fat (g)25.4 (8.0)9.9 (1.8)25.8 (8.1)9.9 (1.8)25.6 (8.5)9.7 (1.8)<0.001de
Polyunsaturated fat (g)14.8 (5.7)5.7 (1.5)15.1 (5.8)5.8 (1.6)15.2 (6.1)5.7 (1.6)0.23
Fibre (g)30.2 (10.3)2.5 (0.6)31.2 (10.3)2.6 (0.6)31.1 (11.1)2.5 (0.6)<0.001ce
  /10 MJ /10 MJ /10 MJ/10 MJ P valuea
  1. a

    One-way anova.

  2. b

    Means (SDs).

  3. c

    Pairwise comparison: SF versus NP significant.

  4. d

    Pairwise comparison: SF versus NVP significant.

  5. e

    Pairwise comparison: NP versus NVP significant.

Retinol (μg)835 (624)864 (584)842 (614)858 (570)860 (681)863 (617)0.51
Beta carotene (μg)2508 (1727)2685 (1785)2598 (1764)2729 (1816)2663 (1918)2770 (2192)<0.001d
Folate (μg)272 (95)287 (69)277 (93)287 (68)280 (103)286 (73)0.88
Niacin (mg)19.1 (4.5)20.5 (3.5)19.3 (4.5)20.3 (3.5)19.2 (4.8)20.0 (3.7)<0.001cde
Riboflavin (mg)1.9 (0.7)2.0 (0.5)2.0 (0.7)2.0 (0.5)2.0 (0.8)2.0 (0.5)<0.001de
Thiamine (mg)1.5 (0.4)1.6 (0.2)1.6 (0.4)1.6 (0.2)1.6 (0.5)1.6 (0.2)<0.001de
Vitamin B6 (mg)1.5 (0.4)1.6 (0.3)1.6 (0.4)1.6 (0.3)1.6 (0.5)1.6 (0.3)<0.001cde
Vitamin B12 (μg)5.9 (2.7)6.3 (2.4)6.0 (2.6)6.2 (2.3)6.0 (2.9)6.1 (2.6)<0.001cd
Vitamin C (mg)160 (87)169 (80)165 (86)171 (81)171 (97)176 (88)<0.001cde
Vitamin D (μg)3.4 (2.3)3.6 (2.1)3.5 (2.2)3.6 (2.0)3.5 (2.5)3.6 (2.1)0.32
Vitamin E (mg)10.5 (3.9)11.0 (2.8)10.8 (4.1)11.1 (2.8)10.8 (4.3)11.0 (2.9)<0.001ce
Iron (mg)11.2 (3.4)11.8 (2.1)11.4 (3.4)11.8 (2.1)11.4 (3.6)11.7 (2.2)<0.001de
Magnesium (mg)398 (114)419 (58)405 (113)418 (58)402 (121)411 (61)<0.001de
Calcium (mg)1038 (416)1085 (300)1054 (416)1082 (299)1051 (452)1065 (322)<0.001de

For the frequency of consumption of specific food items from the FFQ, significant differences between the three groups were found for all food items (P ≤ 0.02; Table 4). NVP had the highest proportion reporting no consumption of specific food items, except for sugar-containing soft drinks. In the most frequent consumption level, the SF group had the highest proportion for chocolate, salty snacks, fresh meat, and artificial sweetener-containing soft drinks. The NP group had the highest number of women with more frequent consumption levels of milk, probiotic-containing dairy food, fresh and processed fish, juice, and water. The NVP group had more frequent consumption of processed meat, vegetables, fruit, and sugar-containing soft drinks.

Table 4. Consumption of specific food items from food frequency questionnaire
 Total n = 51 675Symptom free (SF) n = 14 234Nausea (NP) n = 20 371Nausea and vomiting (NVP) n = 17 070 P a
n (%)n (%)n (%)
  1. a

    Chi-squared test.

  2. b

    Frequency (%).

Milk 51 675    
None57911505 (10.6)b2280 (11.2)2006 (11.8) 
≤12 times/week22 7026337 (44.5)8888 (43.6)7477 (43.8)0.02
≥13 times/week23 1826392 (44.9)9203 (45.2)7587 (44.4) 
Probiotic dairy foods 51 675    
None32 5118964 (63.0)12 304 (60.4)11 243 (65.9) 
Once/week82772158 (15.2)3450 (16.9)2669 (15.6)<0.001
≥Twice/week10 8873112 (21.9)4617 (22.7)3158 (18.5) 
Chocolate 51 675    
None1673327 (2.3)570 (2.8)776 (4.5) 
Once/week15 0233851 (27.1)5699 (28.0)5473 (32.1)<0.001
2–3 times/week21 1126100 (42.9)8498 (41.7)6514 (38.2) 
≥4 times/week13 8673956 (27.8)5604 (27.5)4307 (25.2) 
Salty snacks 51 675    
None1645394 (2.8)604 (3.0)647 (3.8) 
Once/week21 3085638 (39.6)8497 (41.7)7173 (42.0)<0.001
Twice/week16 2924600 (32.3)6469 (31.8)5223 (30.6) 
≥3 times/week12 4303602 (25.3)4801 (23.6)4027 (23.6) 
Fresh fish 51 675    
None46971246 (8.8)1618 (7.9)1833 (10.7) 
Once/week26 5717317 (51.4)10 448 (51.3)8806 (51.6)<0.001
≥Twice/week20 4075671 (39.9)8305 (40.8)6431 (37.6) 
Processed fish 51 675    
None2398625 (4.4)813 (4.0)960 (5.6) 
Once/week11 3563193 (22.4)4212 (20.7)3951 (23.1)<0.001
≥Twice/week37 92110 416 (73.2)15 346 (75.3)12 159 (71.2) 
Fresh meat 51 675    
None668145 (1.0)259 (1.3)264 (1.5) 
1 time/week52421307 (9.2)2032 (10.0)1903 (11.1)<0.001
2–3 times/week24 8776839 (48.0)10 125 (49.7)7913 (46.4) 
≥4 times/week20 8885943 (41.8)7955 (39.1)6990 (40.9) 
Processed meat 51 675    
None46790 (0.6)191 (0.9)186 (1.1) 
1–7 times/week87152348 (16.5)3390 (16.6)2977 (17.4)<0.001
8–14 times/week14 8904286 (30.1)5927 (29.1)4677 (27.4) 
≥15 times/week27 6037510 (52.8)10 863 (53.3)9230 (54.1) 
Vegetables 51 675    
None446133 (0.9)147 (0.7)166 (1.0) 
1–7 times/week23 7916755 (47.5)9060 (44.5)7976 (46.7)<0.001
8–14 times/week19 8305419 (38.1)8092 (39.7)6319 (37.0) 
≥15 times/week76081927 (13.5)3072 (15.1)2609 (15.3) 
Fruit 51 675    
None711196 (1.4)270 (1.3)245 (1.4) 
1–12 times/week20 6955876 (41.3)7873 (38.6)6946 (40.7)<0.001
13–23 times/week24 6606737 (47.3)10 068 (49.4)7855 (46.0) 
≥24 times/week56091425 (10.0)2160 (10.6)2024 (11.9) 
Juice 51 675    
None2283601 (4.2)859 (4.2)823 (4.8) 
≥4 times/week19 0625290 (37.2)7318 (35.9)6454 (37.8)<0.001
5–8 times/week13 6483932 (27.6)5510 (27.0)4206 (24.6) 
≥9 times/week16 6824411 (31.0)6684 (32.8)5587 (32.7) 
Water 51 675    
None1059306 (2.1)355 (1.7)398 (2.3) 
1–28 times/week16 2504449 (31.3)6202 (30.4)5599 (32.8)<0.001
29–49 times/week20 4125593 (39.3)8232 (40.4)6587 (38.6) 
≥50 times/week13 9543886 (27.3)5582 (27.4)4486 (26.3) 
Sugar-containing soft drink 51 675    
None12 3073438 (24.2)5103 (25.1)3766 (22.1) 
Once/week17 3534866 (34.2)7272 (35.7)5215 (30.6)<0.001
≥Twice/week22 0155930 (41.7)7996 (39.3)8089 (47.4) 
Artificial sweetener-containing soft drink 51 675    
None27 2877241 (50.9)10 547 (51.8)9499 (55.6) 
Once/week90292532 (17.8)3714 (18.2)2783 (16.3)<0.001
≥Twice/week15 3594461 (31.3)6110 (30.0)4788 (28.0) 

There were 13 179 (25%) women who had begun to eat/drink certain food items because of the pregnancy (Table 5), with the highest response of answers coming from the NVP group (29.3%). The NVP group had a significantly higher proportion of women consuming foods that reportedly helped to reduce nausea, and foods rich in sugar (P < 0.001). Moreover, the NVP group had a significantly lower proportion of women consuming foods containing probiotics (P < 0.001), with the highest proportion in the SF group. The NP group had a significantly higher proportion of women consuming foods rich in sour/salty taste (P = 0.006). Significantly fewer women in the NVP group began to consume probiotic dairy foods and chocolate (P < 0.001). Conversely, significantly more women in this group began to consume fresh meat, vegetables, water, and soft drinks containing sugar and artificial sweeteners (P ≤ 0.05). The NP group had significantly more women consuming processed meat (P = 0.01).

Table 5. Women beginning to eat or drink general and specific food types during pregnancy, based on self-reported changes in diet
 Total n = 51 675Symptom free (SF) n = 14 234Nausea (NP) n = 20 371Nausea and vomiting (NVP) n = 17 070 P b
n n (%)an (%)n (%)
  1. a

    Frequency (%), percentage of group total.

  2. b

    Chi-squared test.

Began to eat or drink certain foods in pregnancy13 1793087 (21.7)5090 (25.0)5002 (29.3) 
General food categories
Foods reportedly helping to reduce nausea53365 (2.1)201 (3.9)267 (5.3)<0.001
Foods helping digestion (dried fruits etc.)641148 (4.8)265 (5.2)228 (4.6)0.31
Foods containing probiotics1369437 (14.2)588 (11.6)344 (6.9)<0.001
Foods rich in proteins864196 (6.3)326 (6.4)342 (6.8)0.59
Foods rich in fat1219268 (8.7)481 (9.4)470 (9.4)0.46
Foods rich in sugar1768343 (11.1)634 (12.5)791 (15.8)<0.001
Foods using artificial sweeteners13220 (0.6)54 (1.1)58 (1.2)0.07
Foods rich in sour/salty taste812153 (5.0)336 (6.6)323 (6.5)0.006
Specific food items
Milk1774386 (12.5)666 (13.1)722 (14.4)0.29
Probiotic dairy foods1369437 (14.2)588 (11.6)344 (6.9)<0.001
Chocolate23474 (2.4)96 (1.9)64 (1.3)0.001
Fresh fish39997 (3.1)145 (2.8)157 (3.1)0.64
Processed fish26870 (2.3)100 (2.0)98 (2.0)0.57
Fresh meat19427 (0.9)80 (1.6)87 (1.7)0.05
Processed meat727138 (4.5)306 (6.0)283 (5.7)0.01
Vegetables1037208 (6.7)382 (7.5)447 (8.9)0.001
Fruit3938900 (29.2)1491 (29.3)1547 (30.9)0.12
Juice (orange, apple)1623388 (12.6)622 (12.2)613 (12.3)0.89
Water (all types)897163 (5.3)335 (6.6)399 (8.0)<0.001
Sugar-containing soft drinks584101 (3.3)190 (3.7)293 (5.9)<0.001
Artificial sweetener-containing soft drinks13019 (0.1)53 (0.3)58 (0.3)0.001

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information

In the present study we found the 17 070 women with NVP to be the youngest, shortest, and heaviest women, with the shortest duration of education. NVP women also had the lowest GWG, although they had the highest energy intake overall. In response to the FFQ, the NVP group had the highest energy intake percentage-wise coming from carbohydrates and added sugar. In response to specific food items introduced in pregnancy, the NVP group ranked highest in consuming fresh meat, vegetables, water, and sugar and artificial sweetener-containing soft drinks. In response to the FFQ, the SF group consumed the highest protein, fat, and saturated fat percentage-wise. In response to specific foods introduced in pregnancy, they had the highest consumption of probiotic-containing foods and chocolate. Women excluded from the present study tended to have similar ages at delivery, a lower education and income level, as well as a higher parity: findings that are consistent with non-compliance demonstrated in other studies.[30-32] The proportions of those married and cohabiting were likewise similar; cohabitation and marriage are both common in Norway, where cohabitation has developed into an institutionalised alternative to formal marriage.[33]

When combining the NP and NVP groups, 72% experienced nausea. The NVP fraction (33%) is well below the approximately 80% often reported for NVP,[5, 10, 13, 19, 34] probably because of our strict distinction between ‘nausea alone’ and ‘nausea and vomiting’. The SF group had the highest proportion cohabitating, whereas the NP and NVP groups had the highest proportion of married women. A link between marriage and NVP has been reported previously, whereby stress related to poor communication between partners was associated with the severity of NVP.[35] A protective effect against nausea and NVP for smokers is suggested by our findings, supporting previous studies.[5, 8, 35] We found nausea and NVP to be associated with previous experiences of NVP, as was multiparity: findings that support previous studies.[7, 11, 36] Although the NVP group reported the highest energy intake, GWG was lowest in that group. Vomiting has been found to reduce the appetite of pregnant women, and moderate vomiting in pregnancy caused an increased aversion to foods,[37, 38] which may explain the significantly lower GWG in this group. Supporting this, the NVP group in our study responded highest to eating less in response to nausea. Previous studies suggest women with NVP may have aversions to some foods, yet may compensate with other, symptom-alleviating foods, such as sugar-containing soft drinks.[39, 40] Although this may explain the comparatively higher energy intakes, it fails to account for the comparatively lower GWG. When considering the balance of actual energy consumed versus energy regurgitated as a result of vomiting, the energy loss regurgitated could plausibly explain the lower GWG. Another possible cause could be dehydration associated with NVP.[41] Interestingly, we found an interaction effect between BMI and group in the analysis of GWG. Among underweight women, there was no significant difference in GWG. Moreover, GWG was much lower in all three groups among the women who were obese, a finding supported by a large study showing an inverse relationship between BMI and GWG.[42]

The higher intake of carbohydrates and added sugars by the NVP group in this study can be related to the intake of fruit, vegetables, and sugar-containing soft drinks, as reported in the FFQ and in response to new foods consumed. Carbohydrate snacks are often recommended and consumed to help combat the symptoms of NVP.[43] Unsurprisingly, both the NP and NVP groups started to consume ‘foods that reportedly help reduce nausea’, a category composed of high-carbohydrate meals and foods. In a cross-sectional study, the question of whether the high carbohydrate intake is a response to the symptoms, or somehow related to risk, cannot be addressed effectively; however, a previous study has found high-carbohydrate meals exasperate gastric dysrhythmias, which can lead to nauseous effects in pregnancy.[44] Nausea was significantly reduced when subjects were fed high-protein meals, lending some support to the association between carbohydrates and symptoms. Additionally, interviews with women regarding symptom relief reported that consuming high-protein meals were effective against NVP symptoms.[45] The higher intake of saturated fat in the SF group can be related to the more frequent consumption of chocolate and fresh meat, as reported in the FFQ, and chocolate, in response to new foods consumed. In contrast, another study found a high daily intake of saturated fat gave an increased risk of HG, although the question of whether NVP and HG have similar underlying mechanisms has yet to be determined conclusively.[46, 47]

Delayed osmoreceptor adjustment and hyponatremia associated with pregnancy-related plasma changes have also been suggested as increasing the risk for NVP, as the onset of pregnancy involves changes in the body's biochemical environment, causing a resetting of homeostatic osmoreceptors.[45] As plasma volume increases, a haemodilution and subsequent state of hyponatremia is created, causing an environment of decreased plasma osmolality.[45] Homeostasis is mainly achieved via the hormones aldosterone and antidiuretic hormone.[48] Relaxin, a hormone secreted from the corpus luteum and placenta during pregnancy, is also implicated in the resetting of osmoreceptors and hyponatremia.[49] Circulating relaxin has also been shown to stimulate thirst, even in a hyponatremic state.[49] A combination of hyponatremia and excessive thirst is prolonged by progesterone acting as a competitive binder to aldosterone receptors.[50] Supporting this hypothesis, we found the NP and NVP groups both consumed the highest levels of water, as well as foods rich in sour/salty taste, in the list of new foods introduced since pregnancy. We also found that the SF group represented the highest frequency of intake for salty snacks in the FFQ. This may suggest that the SF group was maintaining a better suited fluid osmolarity during the onset of pregnancy, possibly making these women less susceptible to the hyponatremic effects caused by early pregnancy.

Strengths and limitations

The strengths of this study are the large population-based cohort and the validated FFQ.[27] As this is a large cohort, numerous significant associations tend to appear, yet the merit of these in the clinical setting are not always relevant. Measurement errors in the recall of food intake as a whole, and differential measurement errors within the different groups, owing to symptoms of nausea and/or NVP, possibly causing food intake to be reported differently, are potential weaknesses. In spite of the FFQ being validated, FFQs and other tools used to measure diets are associated with both random and systematic errors.[51]

Conclusion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information

To our knowledge, this is the first study addressing dietary intakes in the first trimester of women experiencing NVP, NP, and women who are SF in a very large cohort of pregnant women. The higher intake of carbohydrate and sugar in the NVP group represents foods probably consumed in order to combat symptoms or following the advice received from others.

Disclosure of interests

The authors declare that they have no conflicts of interest. None of the funding bodies had any influence in the design, implementation, analysis, or interpretation of the data in the study.

Contribution to authorship

AC, MH, POI, PM, and MBV designed the project; AC performed statistical analyses, drafted the article, and was responsible for revisions; MH and MBV contributed to the statistical analyses; MH, POI, ÅV, PM, and MBV contributed to the interpretation of the results and the writing of the article. All of the authors critically revised the article and approved the final version.

Details of ethics approval

The present study was conducted according to the guidelines laid down in the Declaration of Helsinki, and all procedures involving human subjects were approved by the Regional Committees for Medical and Health Research Ethics (reference numbers S–97045 and S–95113) and the Norwegian Data Inspectorate. Written informed consent was obtained from all MoBa participants.

Funding

This work was supported by grants from: the Institute of Basic Medical Sciences, University of Oslo; the Throne-Holst Foundation for Nutrition Research; and the Grethe Harbitz Legacy.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information

We are grateful to all of the women and their families for participating in this continuing cohort study.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information
  • 1
    Coad J, Al-Rasasi B, Morgan J. Nutrient insult in early pregnancy. Proc Nutr Soc 2002;61:519.
  • 2
    Ebrahimi N, Maltepe C, Einarson A. Optimal management of nausea and vomiting of pregnancy. Int J Womens Health 2010;2:2418.
  • 3
    Furneaux EC, Langley-Evans AJ, Langley-Evans SC. Nausea and vomiting of pregnancy: endocrine basis and contribution to pregnancy outcome. Obstet Gynecol Surv 2001;56:77582.
  • 4
    Pepper GV, Roberts SC. Rates of nausea and vomiting in pregnancy and dietary characteristics across populations. Proc Biol Sci 2006;2:26759.
  • 5
    Gadsby R, Barnie-Adshead AM, Jagger C. A prospective study of nausea and vomiting during pregnancy. Br J Gen Pract 1993;43:2458.
  • 6
    Chou FH, Chen CH, Kuo SH, Tzeng YL. Experience of Taiwanese women living with nausea and vomiting during pregnancy. J Midwifery Womens Health 2006;51:3705.
  • 7
    O'Brien B, Zhou Q. Variables related to nausea and vomiting during pregnancy. Birth 1995;22:93100.
  • 8
    Källén B, Lundberg G, Aberg A. Relationship between vitamin use, smoking, and nausea and vomiting of pregnancy. Acta Obstet Gynecol Scand 2003;82:91620.
  • 9
    Klebanhoff MA, Koslowe PA, Kaslow R, Rhoads GG. Epidemiology of vomiting in early pregnancy. Obstet Gynecol 1985;66:6126.
  • 10
    Lacasse A, Rey E, Ferreira E, Morin C, Berard A. Epidemiology of nausea and vomiting of pregnancy: prevalence, severity, determinants, and the importance of race/ethnicity. BMC Pregnancy Childbirth 2009;9:2635.
  • 11
    Einarson TR, Navioz Y, Maltepe C, Einarson A, Koren G. Existence and severity of nausea and vomiting in pregnancy (NVP) with different partners. J Obstet Gynaecol 2007;27:3602.
  • 12
    Goecke TW, Ekici AB, Niesler B, Loehberg CR, Hammer C, Rappold G, et al. Two naturally occurring variants of the serotonin receptor gene HTR3C are associated with nausea in pregnancy. Acta Obstet Gynecol Scand 2010;89:714.
  • 13
    Vellacott ID, Cooke EJA, James CE. Nausea and vomiting in early pregnancy. Int J Gynaecol Obstet 1988;27:5762.
  • 14
    Gadsby R, Barnie-Adshead AM, Jagger C. Pregnancy nausea related to women's obstetric and personal histories. Gynecol Obstet Invest 1997;43:10811.
  • 15
    Fairburn CG, Stein A, Jones R. Eating habits and eating disorders during pregnancy. Psychosom Med 1992;54:66572.
  • 16
    Patil CL, Abrams ET, Steinmetz AR, Young SL. Appetite sensations and nausea and vomiting in pregnancy: an overview of the explanations. Ecol Food Nutr 2012;51:394417.
  • 17
    Dickens G, Trethowan WH. Cravings and aversions during pregnancy. J Psychosom Res 1971;15:25968.
  • 18
    Weigel MM, Coe K, Castro NP, Caiza ME, Tello N, Reyes M. Food aversions and cravings during early pregnancy: association with nausea and vomiting. Ecol Food Nutr 2011;50:197214.
  • 19
    Latva-Pukkila U, Isolauri E, Laitinen K. Dietary and clinical impacts of nausea and vomiting during pregnancy. J Hum Nutr Diet 2010;23:6977.
  • 20
    Li CCY, Maloney CA, Cropley JE, Suter CM. Epigenetic programming by maternal nutrition: shaping future generations. Epigenomics 2010;2:53949.
  • 21
    Chang GQ, Gaysinskaya V, Karatayev O, Leibowitz SF. Maternal high-fat diet and fetal programming: increased proliferation of hypothalamic peptide-producing neurons that increase risk for overeating and obesity. J Neurosci 2008;28:1210719.
  • 22
    Irgens LM. The Medical Birth Registry of Norway. Epidemiological research and surveillance throughout 30 years. Acta Obstet Gynecol Scand 2000;79:4359.
  • 23
    Magnus P, Irgens LM, Haug K, Nystad W, Skjaerven R, Stoltenberg C. Cohort profile: the Norwegian mother and child cohort study (MoBa). Int J Epidemiol 2006;35:114650.
  • 24
    Norwegian Institute of Public Health. The Norwegian Mother and Child cohort study (MoBa). Questionnaire 2 current 1 May 2012 [www.fhi.no/dokumenter/011fbd699d.pdf]. Accessed 29 January 2013.
  • 25
    Lauritsen J. FoodCalc. Version current 1 July 2005 [www.ibt.ku.dk/jesper/foodcalc]. Accessed 29 January 2013.
  • 26
    Norwegian Food Safety Authority, Norwegian Directorate of Health, Department of Nutrition - University of Oslo 2005 Matvaretabellen [The Norwegian food composition table, in Norwegian]. Oslo: [www.matvaretabellen.no]. Accessed 7 May 2012.
  • 27
    Brantsæter AL, Haugen M, Alexander J, Meltzer HM. Validity of a new food frequency questionnaire for pregnant women in the Norwegian Mother and Child Cohort Study (MoBa). Matern Child Nutr 2008;4:2843.
  • 28
    Meltzer HM, Brantsæter AL, Ydersbond TA, Alexander J, Haugen M. Methodological challenges when monitoring the diet of pregnant women in a large study: experiences from the Norwegian Mother and Child Cohort Study (MoBa). Matern Child Nutr 2008;4:1427.
  • 29
    World Health Organization. Obesity: Preventing and Managing the Global Epidemic. Geneva: World Health Organization; 2000.
  • 30
    Stacey T, Thompson JM, Mitchell EA, Ekeroma AJ, Zuccollo JM, McCowan LM. The Auckland Stillbirth study, a case–control study exploring modifiable risk factors for third trimester stillbirth: methods and rationale. Aust N Z J Obstet Gynaecol 2011;51:38.
  • 31
    Tough SC, Siever JE, Benzies K, Leew S, Johnston DW. Maternal well-being and its association to risk of developmental problems in children at school entry. BMC Pediatrics 2010;10:19.
  • 32
    Galea S, Tracy M. Participation rates in epidemiologic studies. Ann Epidemiol 2007;17:64353.
  • 33
    Mastekaasa A. Is marriage/cohabitation beneficial for young people? Some evidence on psychological distress among Norwegian college students. J Community Appl Soc 2006;16:14965.
  • 34
    Chan RL, Olshan AF, Savitz DA, Herring AH, Daniels JL, Peterson HB, et al. Maternal influences on nausea and vomiting in early pregnancy. Matern Child Health J 2011;1:1227.
  • 35
    Iatrakis GM, Sakellaropoulos GG, Kourkoubas AH, Kabounia SE. Vomiting and nausea in the first 12 weeks of pregnancy. Psychother Psychosom 1988;49:224.
  • 36
    Louik C. Hernandez Diaz S, Werler MM, Mitchell AA. Nausea and vomiting in pregnancy: maternal characteristics and risk factors. Paediatr Perinat Epidemiol 2006;20:2708.
  • 37
    Taggart N. Food habits in pregnancy. Proc Nutr Soc 1961;20:3540.
  • 38
    Crystal SR, Bowen DJ, Bernstein IL. Morning sickness and salt intake, food cravings, and food aversions. Physiol Behav 1999;67:1817.
  • 39
    Lacroix R, Eason E, Melzack R. Nausea and vomiting during pregnancy: a prospective study of its frequency, intensity, and patterns of change. Am J Obstet Gynecol 2000;182:9317.
  • 40
    O'Brien B, Relyea J, Lidstone T. Diary reports of nausea and vomiting during pregnancy. Clin Nurs Res 1997;6:23952.
  • 41
    Nicolaidis S, Galaverna O, Metzler CH. Extracellular dehydration during pregnancy increases salt appetite of offspring. Am J Physiol 1990;258:R2813.
  • 42
    Chu SY, Callaghan WM, Bish CL, D'Angelo D. Gestational weight gain by body mass index among US women delivering live births, 2004-2005: fueling future obesity. Am J Obstet Gynecol 2009;200:271.e1–7.
  • 43
    McParlin C, Graham RH, Robson SC. Caring for women with nausea and vomiting in pregnancy: new approaches. Br J Midwifery 2008;16:2805.
  • 44
    Jednak MA, Shadigian EM, Kim MS, Woods ML, Hooper FG, Owyang C, et al. Protein meals reduce nausea and gastric slow wave dysrhythmic activity in first trimester pregnancy. Am J Physiol 1999;277:G85561.
  • 45
    Voda AM, Randall MP. Nausea and vomiting of pregnancy: “Morning sickness”. In: Norris CM, editor. Concept Clarification in Nursing. Aspen, CO: Aspen Pub; 1982:13365.
  • 46
    Signorello LB, Harlow BL, Wang S, Erick MA. Saturated fat intake and the risk of severe hyperemesis gravidarum. Epidemiology 1998;9:63640.
  • 47
    Verberg MF, Gillot DJ, Al-Fardan N, Grudzinskas JG. Hyperemesis gravidarum, a literature review. Hum Reprod Update 2005;5:52739.
  • 48
    Gauer OH, Henry JP, Behn C. The regulation of extracellular fluid volume. Annu Rev Physiol 1970;32:54795.
  • 49
    McKinley MJ, Cairns MJ, Denton DA, Egan G, Mathai ML, Uschakov A, et al. Physiological and pathophysiological influences on thirst. Physiol Behav 2004;81:795803.
  • 50
    Quinkler M, Meyer B, Bumke-Vogt C, Grossmann C, Gruber U, Oelkers W, et al. Agonistic and antagonistic properties of progesterone metabolites at the human mineralocorticoid receptor. Eur J Endocrinol 2002;146:789800.
  • 51
    Nelson M, Bingham SA. Assessment of food consumption and nutrient intake. In: Margetts BM, Nelson M, editors. Design Concepts in Nutritional Epidemiology. Oxford: Oxford University Press; 1997. pp 12369.

Supporting Information

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. Acknowledgements
  9. References
  10. Supporting Information
FilenameFormatSizeDescription
bjo12406-sup-0001-AppendixS1.pdfapplication/PDF61KAppendix S1. Catalogue of the categories used to classify foods reported as being newly consumed since conception.
bjo12406-sup-0002-TableS1.pdfapplication/PDF35KTable S1. Comparison of demographics for women included and excluded in the present study from women in the entire MoBa sample.

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