• Open Access

Prevalence of health behaviours in pregnancy at service entry in a Queensland health service district

Authors


Correspondence to: Shelley A. Wilkinson, School of Psychology, The University of Queensland, St Lucia, Brisbane, Queensland, Australia, 4072. Fax: (07) 3163 2442; e-mail: shelley.wilkinson@mater.org.au

Abstract

Objective: Limited prevalence data for unhealthy pregnancy health behaviours make it difficult to prioritise primary prevention efforts for maternal and infant health. This study's objective was to establish the prevalence of cigarette smoking, sufficient fruit and vegetable intake and sufficient physical activity among women accessing antenatal clinics in a Queensland (Australia) health service district.

Method: Cross-sectional self-reported smoking status, daily fruit and vegetable intake, weekly physical activity and a range of socio-demographic variables were obtained from women recruited at their initial antenatal clinic visit, over a three-month recruitment phase during 2007.

Results: Analyses were based on 262 pregnant women. The study sample was broadly representative of women giving birth in the district and state, with higher representation of women with low levels of education and high income. More than one quarter of women were smoking. Few women met the guidelines for sufficient fruit (9.2%), vegetables (2.7%) or physical activity (32.8%) during pregnancy.

Conclusions: There were low levels of adherence to health behaviour recommendations for pregnancy in this sample.

Implications: There is a clear need to develop and evaluate effective pregnancy behaviour interventions to improve primary prevention in maternal and infant health. Brief minimal contact interventions that can be delivered through primary care to create a greater primary prevention focus for maternal and infant health would be worth exploring.

Health behaviours during pregnancy are associated with pregnancy-related and long-term health outcomes for both the mother and infant. Cigarette smoking,1 poor nutrition,2 insufficient levels of physical activity,3 and inappropriate weight gain4 during pregnancy have been associated with a number of poor maternal and infant outcomes. These outcomes include an increased risk of: pregnancy complications,5 caesarean sections,4 low birth weight,1 pre-term birth,4,6 inappropriate weight gain during pregnancy7 and chronic disease in adult life.2,8 Adherence to health behaviour recommendations during pregnancy has been shown to decrease the risk of gestational diabetes mellitus,9 attenuate pregnancy symptoms10 and improve mental health.11,12 Poor pregnancy health behaviours and associated maternal and infant health outcomes have been linked with increased costs of health care delivery through longer hospital admissions and intensive care admissions4,13,14 and greater childhood health care costs.15 Understanding the prevalence of these behaviours is important for health promotion and service planning.

Abstinence from cigarette smoking is recommended during the entire gestational period and there are demonstrated benefits of cessation at any stage of pregnancy.16 Abstinence from cigarette smoking during pregnancy decreases the risk of low birth weight and preterm birth.16 Between 10% and 25% of women give up smoking when they are planning a family or become pregnant,17 but available data indicate that between 12% and 40 % smoke during pregnancy.18

The recommended diet for pregnancy follows the national dietary guidelines. The recommended fruit intake increases from two to four serves during pregnancy.19 In addition, five serves of vegetables per day are recommended during pregnancy.19 Minimal population consumption data are available for fruit and vegetable intake during pregnancy. Moreover, national intake data indicate a low prevalence of recommended consumption of fruit and vegetables in non-pregnant women.20 Therefore, with increased requirements in pregnancy, it is likely that the proportion of women meeting these guidelines is even lower than in the general population.

Moderate exercise for at least half an hour on most, if not all, days is recommended during pregnancy,21 mirroring physical activity guidelines for the general population.22 These guidelines also recommend previously inactive women become active during their pregnancy.23 No Australian data exist for activity levels during pregnancy, however, we know that approximately 50% of non-pregnant women meet physical activity guidelines23 and that pregnancy represents a life stage in which women decrease their physical activity levels.24,25 Thus, it is likely that the prevalence of pregnant women meeting physical activity recommendations is lower than that of the non-pregnant population.

To date, we have limited data on the prevalence of pregnant women's consumption of fruit and vegetables and levels of physical activity. Importantly, no previous studies have collected data on all the health behaviours identified above with regard to their impact on maternal and infant health outcomes in pregnant populations. The lack of data on the prevalence of pregnancy health behaviours make it difficult to establish the need for and to prioritise further primary prevention efforts, or to set targets for healthy pregnancy behaviours at the population level. This study addressed these gaps and aimed to establish the prevalence of cigarette smoking, sufficient fruit and vegetable intake, and sufficient physical activity among women accessing antenatal clinics in a South-East Queensland health service district (HSD).

Materials and methods

Study design and participants

We report data from a cross-sectional study establishing the prevalence of health behaviours during pregnancy among women utilising the antenatal services in one Queensland HSD. Women were recruited for the study from antenatal clinics across one HSD over a three-month phase, from April to June 2007. Midwives invited women to participate during their first visit to the clinic. Eligibility criteria included ability to provide informed consent and to speak and read English. Ethical approval was granted by the relevant university and HSD ethics committees. We collected self-reported data (outlined in measures) using computer-assisted telephone interviewing (CATI).

Based on previous research, we estimated a prevalence of 20% for smoking in a pregnant sample, which would require a sample of 243 to estimate within 5% with 95% confidence.26 Although there are no pregnancy-specific estimates for the other behaviours examined, based on estimates in comparable samples of the general population, we estimated a true prevalence of 55% (± 5%) for adequate fruit intake (requiring a sample size of 374), 20% for adequate vegetable intake (requiring a sample size of 261) and 55% for physical activity (requiring a sample size of 377).26

Measures

Valid and reliable self-report measures of health behaviours were used. Smoking status was assessed using a self-report measure designed to increase disclosure27,28 of current and preconception smoking status. Pre-pregnancy smoking was defined as smoking in the three months prior to pregnancy. Current smoking behaviour was defined as either currently smoking or having quit but having had a cigarette within the past 30 days.27,28 Current smoking quantity was assessed by asking the number of packs of cigarettes smoked in the past week and number of cigarettes per pack.28 The number of cigarettes smoked in the past week was then calculated by multiplying reported packs smoked by cigarettes per pack.28 Self-reported daily fruit and vegetable intake was collected using a modified version of the National Nutrition Survey Short Questions. These items have demonstrated validity,29 and the two-item measure has been validated against objective measures of intake and biochemical markers.30,31 Self-reported physical activity was assessed using the Active Australia Survey (AAS).22 The AAS assesses the frequency and duration of participation in walking, moderate and vigorous physical activity in the past week. Current weight and height were self-reported Body height was recorded in metres and weight was recorded in kilograms or in stones and pounds, which was later converted to metric units. Body Mass Index was calculated as weight (kg)/height (m)2. Overweight was classified as BMI 25 to 29.9 kg/m2 and obese was classified as greater than 30 kg/m2.

Continuous outcome variables relating to fruit and vegetables were assessed as serves consumed per day. Two variables were for this purpose: ‘serves of fruit’ and ‘serves of vegetables’. These variables were both normally distributed (using the Kolmogorow-Smirnov test),32 thus were reported as means and standard deviations. Medians and interquartile ranges were also reported. Physical activity data were summed to determine total minutes of weekly physical activity, as per the AAS manual.22 This captured time spent in activities of walking, vigorous exercise, and vigorous yardwork/gardening. It did not record household chores, occupational or incidental activity.22 In calculation of minutes of physical activity, minutes of vigorous activity was not weighted by two as suggested in the AAS manual,22 as we were interested in absolute minutes active, rather than the association between physical activity dose and health benefits that may be dependent on total energy expenditure. This allowed the creation of the parametric variable “minutes of physical activity”. This was capped at 840 minutes, according to the AAS manual.22 This variable was positively skewed and was reported as median minutes of physical activity and the corresponding IQR.

Categorical outcome variables were also created (i.e. meeting/not meeting guidelines according to public health guidelines for pregnancy). These included: smoking status, sufficient fruit, sufficient vegetables, and sufficient physical activity. Smoking status was defined as ‘non-smoker’ and ‘current smoker’. Consistent with the dietary guidelines, sufficient fruit and sufficient vegetable intakes were defined as women who consumed >4 serves of fruit and >5 serves of vegetables each day.19 A nonparametric physical activity variable with two categories was created. Participants were categorised as engaging in sufficient physical activity using a cut-off of 150 minutes of activity (walking, gardening, moderate or vigorous activity) that occurred in five or more sessions.22

Demographic data were compared with Australian Census data,33–35 National Perinatal data,36 and Queensland Health perinatal and antenatal services benchmarking data37–39 to assess the representativeness of the sample.

Results

Midwives recruited 304 of the 773 (39.3%) pregnant women who attended the antenatal clinic during the recruitment period. Of these, 86.2% completed the CATI survey. The 13.8% who did not complete the CATI survey were unable to be contacted, due to disconnected telephones or not answering our calls. The demographic characteristics of the sample are compared with the HSD and state profile characteristics in Table 1. Our study sample had representation of age groups between state and HSD distributions, and representation of Aboriginal and/or Torres Strait Islander women that closely reflected the HSD profile. Our sample was also less educated, more likely to be in de facto relationships and less likely to be separated/divorced, and had higher household incomes compared with the state and HSD profile. Our sample size provided sufficient power to detect a true prevalence of 55% for sufficient vegetable intake and 20% for smoking status.

Table 1.  Demographic characteristics of the study sample compared with the local Health Service District (HSD) and state populations of women giving birth.
CharacteristicMean (SD, range) or percentage Study Sample (n=262)Percentage HSDPercentage Queensland
  1. Note: a) <$650; $650-799 for HSD and state columns;      b) ABS data (2007 census);

  2. c) AIHW data (2005 mothers and babies);      d) HSD Clinical Benchmarking Department 2007;

  3. NB: some missing/refused to answer data in the study sample results in some %s not equalling 100. Ns are provided to indicate missing data.

Age (years)27.2 (5.8; 16-46)29.1c
  < 20 years9.9%12.0%d5.6%c
  21-25 years24.4%28.0%d17.5%c
  26-30years29.8%28.5%d27.7%c
  31-35 years24.8%21.8%d31.3%c
  >36 years10.7%9.7%d17.9%c
  Missing0.4%
Pre-pregnancy BMI (kg/m2)25.3 (5.8;15.4-50.4)
  Underweight (<18.5)8.0%
  Healthy weight range (18.5-24.9)45.4%
  Overweight (25-29.9)21.0%
  Obese (> 30)20.2%
  Missing5.3%
Education: Did not finish high school60.4%57.1%b48.5%
Household income (gross, per week)
  Less than $600a12.6%35.2%b28.8%b
  $600-799a11.5%7.1%b6.5%b
  $800-9999.9%7.4%b7.1%b
  $1000-199911.5%11.7%b11.6%b
  More than $120042.7%27.9%b34.6%b
  Refused to answer10.3%
  Missing1.5%
Marital status
  Married48.5%49.9%b49.0%b
  de facto34.7%9.5%b10.2%b
  Separated/Divorced5.3%21.9%b18.2%b
  Never Married9.9%36.2%b30.0%b
  Missing1.5%
Private Health Insurance
  Hospital8.8%
  Missing1.5%
  Ancillary services13.7%
  Missing1.5%
Employment
  Full time work24.4%21.5%b26.6%
  Part time/ Casual work25.6%22.6%b23.3%
  Studying0.8%n/availn/avail
  Full time home duties42.4%n/availn/avail
  Unemployed5.3%3.4%b2.9%
  Missing1.5%
Country of birth
  Australia81.7%76.9%b83.3%c
  Pacific Islands4.0%4.7%b4.4%c
  Asia4.0%1.7%b4.3%c
  Europe8.0%8.0%b2.5%c
  Other1.1%1.0%b5.9%c
  Missing1.5%
English (main language) spoken at home93.5%91.0%b86.6%
  Missing1.5%
ATSI status
  Aboriginal and/or Torres Strait Islander4.7%4.0%d5.6%c
  Neither93.9%96.0%d94.3%c
  Missing1.4%
Stage of gestation – weeks19.4 (5.6; 10-38)
  First trimester19.1%
  Second trimester73.7%
  Third trimester7.3%

Health behaviours

The proportion of women who met guidelines for health behaviours that influence maternal and infant health outcomes during pregnancy are illustrated in Figure 1. Few women met the guidelines for sufficient fruit (9.2%) or sufficient vegetable (2.7%) intake. On average, women consumed half the recommended serves of fruit (mean 2.2, SD 1.1; median 2.0, IQR1.0-2.0) and little more than one third of the recommended serves of vegetables (mean 2.0, SD 0.6; median 2.0, IQR 1.0-3.0) per day. Approximately one third (32.8%) of the population was undertaking sufficient physical activity (see Figure 1). Women undertook a median of 112.5 minutes of physical activity per week (IQR 43.8-240.0). A large proportion of women smoked prior to pregnancy (37.8%) and more than one quarter continued to smoke during pregnancy. Approximately 10% of women quit smoking when they became pregnant. On average, women smoked 15.9 cigarettes a day (SD 1.2, n=103) before becoming pregnant and smoked 13.4 cigarettes a day (SD 2.6, n=26) once becoming pregnant. Twenty-one per cent of women were overweight and 20.0% were obese before becoming pregnant.

Figure 1.

Proportion of women meeting health behaviour guidelines for pregnancy.

Discussion

This study aimed to establish the prevalence of health behaviours known to influence maternal and infant pregnancy outcomes among women accessing antenatal clinics in a South-East Queensland HSD. To our knowledge, no other paper has reported the prevalence of these health behaviours simultaneously or compared behaviours with population guidelines. Poor adherence to recommended guidelines for smoking cessation, fruit and vegetable intake, and physical activity behaviours was observed.

The prevalence of cigarette smoking in this study is above the state estimate,36 but is similar to that documented in other studies.18,40 Proportions of women consuming sufficient serves of fruit and vegetables were significantly lower than those in the last reported population intake data.41 A smaller proportion of women were sufficiently physically active compared with the national average for non-pregnant women.23

Given the strong evidence for the role of health behaviours during pregnancy on maternal and infant health, low levels of adherence to public health recommendations for these behaviours are of concern. Continued smoking remains a public health concern requiring effective smoking cessation interventions for pregnant women. The intake of sufficient fruit and vegetables has been proposed as the most important public health message for the decrease of chronic disease.42 Thus, the low prevalence of women meeting the dietary guidelines warrants further attention. There also exists an urgent need to identify and address the barriers to women undertaking sufficient physical activity during pregnancy.

More than 40% of women in this study were overweight or obese at the beginning of pregnancy. Overweight and obesity in pregnancy is associated with an increased risk of maternal and infant health complications.4 Evidence also suggests that awareness of weight gain guidelines may influence pregnancy weight gain. Cogswell et al. (1999) demonstrated that women advised to gain less or more than the Institute of Medicine weight gain guidelines were 3.6 times more likely to report actual gains below or above recommendations, compared with women advised to gain within the guidelines.43 Women not advised about weight gain were more likely to gain weight outside the recommended weight gain range.43 It is important that all pregnant women have knowledge of pregnancy weight gain guidelines.

Our recruitment rate was similar to other epidemiological studies that attempt to estimate population prevalence of health behaviours,25,44 and as expected given our method of recruitment45 via antenatal clinic staff, rather than dedicated research staff. However, we may have had more than acceptable error in our estimation of prevalence of sufficient fruit intake and sufficient physical activity with our sample size. We did not collect pregnancy history information or demographic details about women who were approached but did not consent to participate. This procedure would have provided a richer picture of our study participants. However, the demographics of our study sample demonstrate fair representativeness of young women and women with lower levels of education, despite documented difficulties in the engagement of these groups in research more generally46 and their less regular use of antenatal services.47,48 We still had a lower representativeness of women from lower income households, but given what we know about the associations between socio-economic status and healthy behaviours,40,49,50,51 such sampling bias would only have resulted in an underestimate of the actual size of the problem. Nevertheless, this does limit the generalisability of the results beyond the sample population and points to a continued need for future studies to focus on recruiting marginalised groups.

A strength of the study is the use of CATI to circumvent literacy issues that may be apparent in written self-report studies.45,52 Additionally, the collection of data regarding a suite of health behaviours at the start of pregnancy is the first reported study of this kind. The use of self-report measures also introduces potential biases. Objective measures of all behaviours may have strengthened findings. The tools selected were valid, reliable and suitable for telephone delivery.53,54

Future recommendations

These results suggest three important avenues for investigation and effective practice changes that can be implemented. First, as data have not previously been collected regarding these health behaviours during pregnancy, tracking of behaviour change throughout pregnancy is recommended. Second, research investigating patterns of occurrence of multiple risk factors for unhealthy behaviours, particularly stratification according to socio-demographic and other health behaviours would provide more information for planning interventions. Finally, there is a need to support women who face greater barriers to meeting health recommendations. Structuring health services to allow systematic delivery of support and services to women in this environment would be one avenue to reach women at a time in which the majority of them are in contact with the health service.55 Positioning pregnancy care in accessible community locations to enable greater service utilisation and accessibility is recommended.56

Conclusion

This paper documented the prevalence of health behaviours in a pregnant population within a Queensland HSD. We found low levels of adherence to recommendations known to influence pregnancy maternal and infant health outcomes, including high rates of cigarette smoking, and low rates of sufficient fruit and vegetable consumption and physical activity. These findings highlight that there is now a clear need to develop and evaluate effective interventions to address these problems. Brief minimal contact behavioural interventions that can be delivered through primary care to create a greater primary prevention focus for maternal and infant health as a practical step to address these health issues would be worth exploring.

Acknowledgments

This research was funded by Queensland Health to meet the requirements of a larger project (The Development of a Food, Nutrition, and Physical Activity Project for Pregnancy and Early Life) which was conceived and developed by a group of interdisciplinary researchers at The University of Queensland. Funding was also received from the Redcliffe Hospital Foundation. We would like to thank Meredith Shallcross and staff of the Redcliffe-Caboolture Health Service that participated in the recruitment for this study project. We are grateful to the ‘Caboolture mums and little ones’ and the ‘Redcliffe Health Behaviours in Pregnancy’ data collection interviewers and to the women who participated in the survey for their valuable contribution.

Ancillary