Fear of childbirth in nulliparous and multiparous women: a population-based analysis of all singleton births in Finland in 1997–2010

Authors


Abstract

Objective

To identify risk factors for fear of childbirth (FOC) according to parity and socioeconomic status, and to evaluate associations between FOC and adverse perinatal outcomes.

Design

A cohort study.

Setting

The Finnish Medical Birth Register.

Population

All 788 317 singleton births during 1997–2010 in Finland.

Methods

Fear of childbirth was defined according to the International Classification of Diseases code O99.80, and its associations with several risk factors and perinatal outcomes were analysed by multivariable logistic regression.

Main outcome measures

Prevalence of, risk factors for and outcomes of FOC.

Results

Fear of childbirth was experienced by 2.5% of nulliparous women and 4.5% of multiparous women. The strongest risk factors for FOC in nulliparous women were depression [adjusted odds ratio (aOR), 6.35; 95% confidence interval (CI), 5.25–7.68], advanced maternal age (aOR, 3.78; 95% CI, 3.23–4.42) and high or unspecified socioeconomic status. In multiparous women, the strongest risk factors for FOC were depression (aOR, 5.47; 95% CI, 4.67–6.41), previous caesarean section (CS) (aOR, 3.02; 95% CI, 2.93–3.11) and high or unspecified socioeconomic status. Among both nulliparous and multiparous women, FOC was associated with higher rates of CS (3.3-fold and 4.5-fold higher, respectively) and a lower incidence of low birthweight (<2500 g), small for gestational age babies, preterm birth and low Apgar scores at 1 minute.

Conclusions

High and unspecified socioeconomic status, advanced maternal age and depression are predisposing factors for FOC regardless of parity. Among multiparous women, a previous CS increases vulnerability to FOC. FOC is associated with increased rates of CS, but does not adversely affect other pregnancy outcomes.

Introduction

Fear of childbirth (FOC) has been defined in various ways, and the related literature is therefore inconsistent. Individually, each woman defines FOC herself when she asks for help, but, in general, FOC can be seen as an anxiety disorder or as a phobia manifesting as nightmares, physical complaints, concentration difficulties on work and family activities, and as a request for caesarean section (CS).[1] The prevalence of FOC seems to depend on several factors, such as the definition of the condition, measurement tools and cultural context. Previous population-based studies have found that FOC complicates 7.6–17.8% of pregnancies,[2-5] and is more severe in nulliparous than in multiparous women.[6-8] FOC has been shown to be associated with pain, previous childbirth experiences,[2, 6, 8, 9] previous obstetric complications,[9] such as a previous emergency CS,[2] a woman's personality characteristics, such as anxiety, low self-esteem or dissatisfaction with her partner, lack of social support[10] and emotional, physical or sexual abuse in childhood.[11] An increased incidence of FOC has also been associated with maternal characteristics, including young age, low level of education, unemployment, smoking,[4, 12] single marital status[8] and depression.[10, 13, 14]

Several studies have evaluated the association between FOC and adverse perinatal outcomes. Although some studies have found FOC to be associated with an increased prevalence of elective[15] and emergency CS,[2, 5, 12] others have found no association between FOC and the mode of delivery.[3, 16] Further, women with FOC have a higher risk of a prolonged or protracted childbirth,[3, 12, 17] but not of complicated fetal distress, compared with women without FOC.[12] Several previous studies including animal experiments have demonstrated prenatal maternal stress and anxiety to be associated with adverse perinatal outcomes, such as preterm birth and restricted fetal growth,[18-20] unfavourable development of the child,[21] and chronic diseases, such as diabetes, in adulthood.[20] However, conclusions for women with anxiety disorders were limited, as most studies used instruments not highly validated for the purpose and included pregnant women with elevated symptoms.[19]

The aims of this register-based cohort study were to identify risk factors for FOC as defined in the International Classification of Diseases (ICD), according to parity (separately for nulliparous and multiparous women) and socioeconomic status (SES), and to evaluate associations between FOC and perinatal outcomes among the total population of singleton births in Finland, starting from 1997 when FOC was included in Finnish hospital registries. This is the first analysis of FOC risk factors covering the entire population of a country over a long period, and the first to include factors such as in vitro fertilisation (IVF) and outcomes such as stillbirth, small for gestational age (SGA) births and low birthweight (LBW).

Materials and methods

Data collection and study population

The primary source of the data used in this study was the Finnish Medical Birth Register (MBR), which was started in 1987 and contains demographic and medical information recorded during the first postnatal week on all live births, stillbirths delivered after the 22nd gestational week and babies weighing 500 g or more. The study was restricted to the population of singleton births from 1997 to 2010 (n = 788 317). Multiple pregnancies were excluded as they carry higher risks of complications.

Medical Birth Register data were supplemented by ICD-10 codes gathered from the Hospital Discharge Register (HDR), which was established in 1969 and contains information on all aspects of inpatient care and outpatient visits in Finnish hospitals. FOC was defined as described previously,[1] and has been based on the national ICD-10 code O99.80 since 1997, and thus it was possible to identify women with FOC in the study population in the HDR.

In Finland, all pregnant women are asked about their feelings towards childbirth in primary health care, and women experiencing significant FOC who cannot be counselled during antenatal visits in primary health care or who have requested CS because of FOC are referred to specialist maternity care. FOC is diagnosed if a woman is referred for specialist maternity care as a result of FOC or if FOC is manifested and is dealt with at maternity care visits. In Finland, almost all delivery hospitals have a phobia clinic with trained staff having special expertise in diagnostic workup and counselling for women experiencing FOC. In phobia clinics, women undergo obstetric assessment and are supported and treated on the basis of their individual needs, and nobody is forced to undergo a vaginal birth.[22] Furthermore, in many phobia clinics, women have the possibility to reflect on their birth experiences and to provide feedback about their delivery care.

Information on major congenital anomalies until 1 year of age was gathered from the Congenital Malformations Register (CMR). The MBR, CMR and HDR are currently maintained by the National Institute for Health and Welfare of Finland, and the information gathered from the registers was linked together using the women's encrypted unique personal identification numbers.

Variables and definitions

We used maternal occupation at childbirth as a marker of SES based on Finland's National Classification of Occupations, and categorised the study population into the following five groups: (i) upper level white collar workers, such as physicians and teachers; (ii) lower level white collar workers, such as nurses and secretaries; (iii) blue collar workers, such as cooks and cleaners; (iv) others; or (v) missing information, as described previously.[23] The group labelled ‘others’ comprised 25.1% (197 785) of the women for whom SES could not be defined, including entrepreneurs, students, retired women, unemployed women, housewives and all unclassifiable occupations. The ‘missing’ SES information category comprised 15.9% (125 290) of all women. Women were also categorised on the basis of self-reported smoking habits during pregnancy into four groups: non-smokers; quitters (those who quit smoking during the first trimester); smokers (those who continued smoking after the first trimester); or missing data (those for whom data were not recorded). Information on the number of cigarettes smoked per day was not available.

Women were classified as nulliparous (no previous childbirths) or multiparous (one or more previous childbirths). Maternal age was categorised as <20, 20–29, 30–39 or 40 years or more. Advanced maternal age was defined as 40 years or more. The gestational age was estimated on the basis of first- or second-trimester ultrasonography measurements or from the date of the last menstrual period. Mode of delivery was categorised as spontaneous vaginal, breech, forceps, vacuum assisted or CS. Elective and emergency CS were not separated as, if planned CS is performed outside office hours for some reason, it may be recorded as emergency or other CS. Preterm birth was defined as childbirth at gestational week 37 or earlier. The infant was considered to be SGA when the sex- and parity-specific birthweight was more than two standard deviations (SDs) below the mean gestational weight for the Finnish reference population,[24] and considered to have LBW when the birthweight was <2500 g. One- and 5-minute Apgar scores of ≤6 and newborn vein pH < 7.15 were considered to be low. Stillbirth was defined as fetal death from 22 gestational weeks onwards. Early neonatal death was defined as death occurring within the first seven postnatal days. Maternal anaemia was defined as haemoglobin levels ≤ 6.2 mmol/l. Women were recorded as either married/living with a partner or single. IVF records included information on the use of intracellular sperm injection and frozen embryo transfers. Depression was defined according to ICD-10 codes F31.3, F31.5 and F32–34, and categorised into four groups: depression before pregnancy; before and during pregnancy; during pregnancy alone; or no depression. The study period was subdivided into three periods to detect possible secular trends: 1997–2001; 2002–2006; and 2007–2010.

Statistical analyses

The significance of differences between women with and without FOC was evaluated using chi-squared tests for dichotomous or categorical variables and Mann–Whitney U-tests for continuous variables. The analyses were conducted separately for nulliparous and multiparous women. Risk factors for FOC according to parity and its associations with adverse perinatal outcomes (preterm birth, LBW, SGA, admission to neonatal intensive care, low Apgar score, low newborn vein pH, stillbirth and early neonatal death) were determined by multivariate logistic regression analyses. Possible risk factors for FOC were selected on the basis of bivariable analyses, and final models are presented. If a woman was affected by several adverse perinatal outcomes, each was considered as an independent outcome and the pregnancy was included in all categories. We also performed multiple imputations to study whether missing information on SES affected our results of logistic regression analysis. Differences were deemed to be significant if P < 0.05. In addition, 95% confidence intervals (CIs) were calculated. The data were analysed using SPSS for Windows 19.0 (Chicago, IL, USA).

Results

According to the Finnish MBR, there were 788 317 singleton childbirths in Finland from 1997 to 2010. FOC was experienced by 2.5% of nulliparous women (8039 of 327 176) and 4.5% of multiparous women (20 921 of 461 141). In parous women, FOC was most common after first previous vaginal or caesarean birth (P ≤ 0.001). During the study period, the prevalence of FOC increased from 1.1 to 3.6% in nulliparous women, and from 1.5 to 7.8% in multiparous women. Compared with women without FOC, those with FOC were significantly older, and more often gave birth at low gestational age, by CS, and more often experienced reproductive risks, such as miscarriages, previous early termination of pregnancy, anaemia, gestational diabetes, maternal diabetes mellitus, or underwent IVF procedures or chorionic villus biopsy (Supporting information Table S1). Socioeconomic differences were also observed: pregnancies among single women and upper level white collar workers were more often complicated by FOC. Demographics and delivery characteristics according to FOC and SES are presented in Tables S2 and S3. The incidence of previous early termination of pregnancy was higher in blue collar workers than in the other SES classes, and across all classes significantly higher among women with FOC than among those without FOC.

After adjustment for maternal age, smoking status, marital status, reproductive history (previous miscarriages, previous early termination(s), IVF, CS), depression, pre-eclampsia, gestational diabetes, maternal diabetes mellitus and major congenital anomalies, FOC appeared to be most prevalent in upper level white collar workers and unspecified SES groups, regardless of parity (Table 1). Increased prevalence of FOC was also associated with the following: giving birth at an advanced maternal age (≥40 years), single marital status, giving up smoking, previous early terminations, depression before and/or during pregnancy and gestational diabetes in both groups; smoking in nulliparous women; and IVF, a previous CS and major congenital anomaly in multiparous women (Table 1). FOC was associated with 3.4- and 4.4-fold higher CS prevalence in nulliparous and multiparous women, respectively, and 8% higher frequency of admission to a neonatal intensive care unit among multiparous women (Table S4). Interestingly, in both parity groups, FOC was associated with lower incidences of preterm birth, LBW, SGA, low Apgar scores at 1 minute, stillbirth and early neonatal death relative to women without FOC.

Table 1. Adjusted odds ratios (ORs) of fear of childbirth in nulliparous and multiparous women with singleton childbirths during 1997–2010 in Finland (logistic regression)
CharacteristicNulliparous women (n = 302 479)Multiparous women (n = 442 992)
Adjusted OR (95% CI)Adjusted OR (95% CI)
  1. NA, not applicable.

  2. a

    Others includes entrepreneurs, students, retired, unemployed, housewives and all unclassifiable cases.

Maternal age (years)
≤19 (ref. for nulliparous)1 
20–29 (ref. for multiparous)1.07 (0.96–1.19)1
30–391.98 (1.76–2.20)1.23 (1.19–1.26)
≥403.78 (3.23–4.42)1.23 (1.15–1.31)
Smoking status
Non-smoking11
Quit smoking1.18 (1.06–1.31)1.27 (1.16–1.39)
Smoking1.15 (1.07–1.23)0.93 (0.89–0.98)
Missing1.15 (0.98–1.34)1.11 (1.02–1.21)
Being single (ref. married/living with a partner) 1.24 (1.15–1.34)1.07 (1.00–1.14)
Socioeconomic status
Upper level white collar worker1.44 (1.30–1.59)1.66 (1.56–1.76)
Lower level white collar worker1.09 (1.00–1.18)1.27 (1.21–1.33)
Blue collar worker11
Othera1.41 (1.30–1.53)1.46 (1.39–1.54)
Missing1.63 (1.50–1.78)1.77 (1.68–1.87)
Previous miscarriages 1.03 (0.97–1.10)1.00 (0.97–1.03)
Previous early terminations 1.27 (1.19–1.36)1.17 (1.12–1.22)
In vitro fertilisation (IVF) 1.07 (0.93–1.24)1.25 (1.08–1.44)
Previous caesarean section NA3.02 (2.93–3.11)
Depression
No11
Before pregnancy only3.36 (3.03–3.69)3.59 (3.36–3.83)
During pregnancy only5.87 (4.88–7.07)4.15 (3.58–4.81)
Before and during pregnancy6.35 (5.25–7.68)5.47 (4.67–6.41)
Major congenital anomaly 1.07 (0.95–1.20)1.09 (1.02–1.17)
Pre-eclampsia 0.48 (0.34–0.68)0.47 (0.41–0.54)
Gestational diabetes 1.21 (1.06–1.38)1.25 (1.17–1.33)
Maternal diabetes mellitus 0.89 (0.76–1.03)0.94 (0.87–1.01)

Discussion

Main findings

Of the nulliparous and multiparous women who gave birth to singletons recorded in Finland from 1997 to 2010, 2.5 and 4.5% experienced FOC, respectively. These proportions are substantially lower than the 7.6–17.8% reported in previous population-based studies,[2-4] possibly as a result of the use of the ICD-10 code (O99.80) to define FOC in the present study rather than just symptomatic descriptions. The prevalence of FOC was 1.9-fold higher among multiparous than nulliparous women. Women with high and unspecified SES more often experienced FOC than women with low SES. Increased prevalence of FOC was also observed in pregnant women characterised by advanced maternal age, living without a partner, with previous early terminations of pregnancy, and suffering from depression or gestational diabetes, regardless of parity. Further, in nulliparous women, FOC was also associated with smoking and, in multiparous women, with reproductive history (including IVF and previous CS) and major congenital anomaly. FOC was associated with up to 4.4-fold higher CS rates and lower incidences of preterm birth, LBW, SGA, low Apgar scores at 1 minute, stillbirth and early neonatal death.

Strengths and limitations

In the present study, data on childbirths from the entire country during a 14-year period were analysed, and FOC was defined according to the ICD-10 code. The data gathered from the mandatory national MBR were supplemented with information gathered from two other mandatory national health registries: HDR and CMR. The unique identification number of each woman enabled robust cross-linking between the three registries, which are considered to have excellent coverage and quality,[25-27] and the unique dataset enabled a much more rigorous analysis of associations of demographic factors, such as maternal age, parity and SES, with FOC than was possible in smaller scale studies.[2, 7, 10, 13]

A limitation is that SES was undefined for one of four women (25.1%, n = 197 785), which may be a result of the inclusion of young mothers and high proportions of students and stay-at-home mothers. Further, information on SES was missing for 15.9% (125 290) of women. Reporting of SES is optional and, because of the sensitive nature of this information or confidentiality reasons, a large number of women did not provide it. However, the demographic characteristics of this group were close to those of the general population, suggesting that they do not differ meaningfully with regard to other covariates, and multiple data imputations of missing information did not change the results (data not shown). The use of ICD-10 codes for FOC limits the diagnosed cases to women with severe FOC, e.g. those who require referral to phobia clinics and those who demand CS because of FOC. It is outside the scope of this study to investigate women with FOC who were handled in primary care.

Interpretation

Multiparous women in our study population experienced FOC more often than nulliparous women. This is in stark contrast with previous findings (from analyses of smaller datasets) indicating that FOC is more common[8] and more severe[7, 10] among nulliparous women. However, our results are consistent with reports of associations between previous childbirth experiences and FOC in a subsequent pregnancy.[6, 17] In the present study, in multiparous women, FOC was most common after one previous vaginal or caesarean birth, reflecting the importance of experience as a predisposing factor. Increasing prevalence of FOC during the study period could be partially explained by the fact that counselling services were introduced about 15 years ago, and the ICD-10 code was applied from 1997 to obtain information on the prevalence and counselling services for women with FOC.[22] In previous studies, an increased prevalence of FOC was reported among pregnant women characterised by a lower educational level,[12] unemployment,[8, 10] depression[13, 14] and young maternal age (<20 years).[12] Our results are only partially consistent with these previous results, as we found that women with high SES and advanced maternal age experienced FOC more frequently than those with low SES and younger maternal age. The discrepancies may be a result of our use of a sufficiently large and comprehensive dataset to detect differences in FOC between SES and maternal age groups that were missed by previous studies.[2, 10, 13] Our results indicate that women are likely to have FOC if high-risk pregnancy factors are present, such as gestational diabetes, advanced age or an actual complication, such as congenital anomaly. Giving birth at an advanced age has been increasing,[28] and was most common among women with high SES. In accordance with our findings, a previous study reported that women with university level education tended to be more critical and have more negative experiences related to childbirth than controls with lower education levels.[8]

Our results did not confirm an association between adverse perinatal outcomes and maternal stress and anxiety during pregnancy,[18-20] as FOC did not adversely affect the outcome of pregnancy. Instead, pregnancies of women with FOC were complicated less frequently by preterm birth, LBW, SGA, low Apgar scores at 1 minute, stillbirth and early neonatal death, which might be explained by the successful counselling of FOC. Previous randomised controlled studies have shown appropriate counseling of FOC to be successful, as women in the study groups reported more positive birth experiences and underwent CS less frequently than controls.[29, 30] However, FOC was associated with 3.3- and 4.5-fold higher rates of CS among nulliparous and multiparous women, respectively (increases from 19 to 45.4% and 11.9 to 37.2%, respectively). Smaller population-based studies have reported increases in CS rates of the order of 30% among women with FOC.[2, 5] FOC resulted in 6.5 extra cases of CS per 1000 births for nulliparous women and 11.5 extra cases of CS per 1000 births for multiparous women. Although we do not have information on the duration of parturition, previous studies have shown FOC to be associated with prolonged or protracted childbirth among women who experience FOC.[3, 12, 17]

Conclusions

We conclude that an increased risk of FOC, as defined by the ICD-10 code, was associated with high SES, a lack of social support which may occur from living without a partner or depression, and high-risk pregnancy factors, such as advanced maternal age, gestational diabetes and major congenital anomaly. With the exception of a high caesarean delivery rate, the outcome of pregnancy was uneventful in women experiencing FOC. Our results concerning an association between FOC and adverse perinatal outcomes were opposite to those of previous studies, and further studies are required to determine whether good perinatal outcomes are a result of counselling of FOC, which is an important clinical issue.

Disclosure of interests

None to declare. All authors declare independence from any funding agency for this work.

Contribution to authorship

SR, SML, HSN, MG, MRK and SH participated in the design of the study. SR managed the dataset and performed statistical analyses. SML, HSN, MG, MRK and SH gave advice regarding the statistical analyses. All authors contributed to the interpretation of the results, as well as to the writing and editing of the manuscript.

Details of ethics approval

Permission to use the confidential register data in this study was approved on 16 February 2012 by the National Institute for Health and Welfare (THL) in Finland (Reference number 1749/5.05.00/2011).

Funding

We have no funding sources to declare.

Acknowledgement

We thank Sees-Editing Ltd. for linguistic assistance.

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