Design and evaluation of a regional perinatal audit.

OBJECTIVE: To describe the experiences of a regional audit of perinatal deaths, including the experiences of the audit members, to discuss similarities and differences with other, existing perinatal audits and to summarize the implications for future implementation. STUDY DESIGN: Perinatal audit with blinded regional auditors. Consecutive cases of perinatal death were analysed for the presence of substandard care. A random selection of cases was reviewed by an external audit panel. The prevalence of substandard care in the Amsterdam audit was compared with other, existing audits. A survey among audit members was executed. RESULTS: Care providers from all Amsterdam hospitals, as well as general practitioners and independent midwives cooperated. One hundred thirty-seven perinatal deaths were reviewed. In 25% of all perinatal death cases, substandard care factors were present. After 23 completed weeks substandard care factors were present in 35% of cases, and in 52% of intrapartum deaths. These figures are comparable with other, non-regional oriented audits. The review of the external panel was also comparable to the review of the regional audit committee. All audit members felt secure to discuss freely the presence of substandard care. CONCLUSION: First systematic experiences with a regional perinatal audit are described. We conclude that a regional perinatal audit is executable. Cooperation of regional care providers is good. Review of substandard care factors is comparable to other, non-regional oriented perinatal audits.

Ethnic differences in perinatal mortality. A perinatal audit on the role of substandard care.

OBJECTIVES: The objective was to investigate the contribution of substandard care to ethnic inequalities in perinatal mortality. STUDY DESIGN: Perinatal audit in Amsterdam, the Netherlands. The study population consisted of 137 consecutive perinatal death cases (16 weeks GA-28 days after delivery). A standardized procedure to establish the cause of death and substandard care by perinatal audit was developed. The main outcome measures were perinatal mortality rates in ethnic groups, cause of death classified by extended Wigglesworth classification, presence of substandard care (unlikely to be, possibly or likely to be related to perinatal death), and component of care considered to be substandard. RESULTS: In Surinamese and other non-Western mothers (mainly from Ghana) perinatal mortality, beyond 16 weeks' gestation, was statistically significantly higher than among native Dutch mothers. (4.01, 2.50, and 1.07%, respectively). In Surinamese and Moroccan mothers, we observed a higher rate of early preterm deliveries. The prevalence of substandard care differed statistically significantly among ethnic groups (p=0.034), with the highest prevalence among Surinamese mothers. These differences were especially apparent in the prevalence of (more) maternal substandard care factors among Surinamese and Moroccan mothers. These factors consisted of a later start date for antenatal care or a later notification by the caregiver about obstetrical problems (e.g. rupturing of membranes, decrease in foetal movements). CONCLUSIONS: The higher perinatal mortality in Surinamese and other non-Western groups is mainly due to a higher rate of early preterm deliveries. No differences in care were observed among ethnic groups during labour and delivery. Among Surinamese mothers, however, the results indicate that substandard care with maternal involvement plays a role in explaining their higher perinatal mortality rates.

Dutch women's decision-making in pregnancy and labour as seen through the eyes of their midwives.

OBJECTIVE: a national study of midwives' perceptions of women's decision-making in the technical interventions in the birth process. DESIGN: questionnaire survey of women and their midwives. Midwives completed a maternity record for each woman in the study after the birth, and the women completed a demographic questionnaire at to 20-24 weeks gestation. SETTING: a stratified sample of 25 Dutch midwifery practices based on rural or urban location. Each of these 25 independent practices agreed to approach 25 eligible consecutive pregnant women on a randomly assigned day. PARTICIPANTS: in total 637 women were invited and 625 participated (response rate 98%). FINDINGS AND KEY CONCLUSIONS: midwives reported that they had a large influence in the decision to refer a woman to an obstetrician, but far and far less so when it comes to decisions around taking pharmaceutical pain relief. Midwives felt women had least say in the decision around augmentation of labour and most in the decision to sweep the membranes, whilst obstetricians had most input in the decision around primary induction of labour and least in the decision to refer from primary to secondary care. Our analysis indicated that midwives saw younger women (29 and younger) as having more influence in the decision-making process than old ones. Our analysis suggests there might be a tension between midwives own professional ideology and their non-interventionist focus and women's choice, which leads to an increase in medicalisation of childbirth.

Maternal nutrition during gestation and carotid arterial compliance in the adult offspring: the Dutch famine birth cohort.

OBJECTIVE: Experimental evidence indicates that maternal undernutrition during gestation may program hypertension in the offspring. We investigated whether maternal undernutrition leads to increased arterial stiffness. METHODS: We measured carotid artery lumen diameter (LD), distensibility (DC), stiffness (beta), and compliance (CC) by M-mode ultrasound in 673 individuals, aged 56-61 years, who had been born as term singletons around the time of the 1944-45 Dutch famine. RESULTS: Maternal famine exposure had no effect on any of the measures of carotid size or stiffness in the offspring. Low maternal weight at the end of pregnancy and low birth weight were associated with decreased LD (0.01 mm/kg maternal weight, sex-adjusted P < 0.001; 0.1 mm/kg birth weight, sex-adjusted P = 0.08) and CC (0.002 mm2/kPa per kg maternal weight, sex-adjusted P = 0.001; 0.03 mm2/kPa per kg birth weight, sex-adjusted P = 0.03), but neither was associated with increased beta, or decreased DC. These effects were not attenuated by adjusting for maternal protein/carbohydrate ratio in the third trimester. The association of low birth weight with increased CC diminished after adjusting for maternal weight. The association of maternal weight with CC was smaller when adjusted for LD. CONCLUSION: Our findings suggest that small maternal size, not poor maternal diet, in late gestation programs decreased arterial compliance in the adult offspring by affecting vessel size rather than vessel wall stiffness.

Patient refusal of emergency cesarean delivery: a study of obstetricians' attitudes in Europe.

OBJECTIVE: To compare the attitudes of a large sample of obstetricians from eight European countries toward a competent woman's refusal to consent to an emergency cesarean delivery for acute fetal distress. METHODS: Obstetricians' attitudes in response to a hypothetical clinical case were surveyed through an anonymous, self-administered questionnaire. The sample included 1,530 obstetricians (response rate 77%) from 105 maternity units (response rate 70%) in eight countries: France, Germany, Italy, Luxembourg, Netherlands, Spain, Sweden and the United Kingdom. RESULTS: In every country, the majority of obstetricians would keep trying to persuade the woman, telling her that failure to perform cesarean delivery might result in the fetus surviving with disability, or even that her own life might be endangered. In Spain, France, Italy, and, to a lesser extent, Germany and Luxembourg, a consistent proportion of physicians would seek a court order to protect fetal welfare or avoid possible legal liability or both. In the United Kingdom, Sweden, and Netherlands, several respondents (59%, 41%, and 37%, respectively) would accept the woman's decision and assist vaginal delivery. Only a small minority (from 0 in the United Kingdom to 10% in France) would proceed with cesarean delivery without a court order. CONCLUSION: Case law arising from a few countries (United States, Canada, and the United Kingdom) and professional guidelines favoring women's autonomy have not solved the underlying ethical conflict, and in Europe acceptance of a woman's right to refuse cesarean delivery, at least in emergency situations, is not uniform. Differing attitudes between obstetricians from the eight countries may reflect diverse legal and ethical environments. LEVEL OF EVIDENCE: III.

Early onset of coronary artery disease after prenatal exposure to the Dutch famine.

BACKGROUND: Limited evidence suggests that maternal undernutrition at the time of conception is associated with increased cardiovascular disease risk in adult offspring. OBJECTIVE: We investigated whether persons conceived during the Dutch famine of World War II had an early onset of coronary artery disease (CAD). DESIGN: We compared the age at onset and cumulative incidence of CAD between persons born as term singletons who were exposed to the 1944-1945 Dutch famine during late (n = 160), mid- (n = 138), or early (n = 87) gestation and 590 unexposed subjects at age 50 or 58 y. Age at CAD onset was defined as the age at which angina pectoris was identified (according to the Rose questionnaire), Q waves were observed on an electrocardiogram (Minnesota codes 1-1 or 1-2), or coronary revascularization was performed (by angioplasty or bypass surgery). RESULTS: Of the 83 CAD cases identified, persons conceived during the famine were 3 y younger than the unexposed persons at the time of CAD diagnosis (47 y compared with 50 y) and had a higher cumulative incidence of CAD [13%; hazard ratio (HR) adjusted for sex: 1.9; 95% CI: 1.0, 3.8] than did the unexposed persons. The HR changed little after adjustment for smoking (HR: 1.8), social class (HR: 2.0), or size at birth (HR: 2.0). CONCLUSIONS: We found an earlier onset of CAD among persons conceived during the famine, which suggests that maternal nutrition in early gestation may play a role in the onset of CAD. This finding agrees with evidence from animal experiments that identify periconceptional maternal diet as important in the offspring's adult health.

Blood pressure response to psychological stressors in adults after prenatal exposure to the Dutch famine.

OBJECTIVE: There is increasing evidence that restricted prenatal growth is associated with exaggerated blood pressure responses to stress. We investigated the effect of maternal undernutrition on the adult offspring's stress response. DESIGN: A historical cohort study. METHODS: We performed continuous blood pressure and heart rate measurements during a battery of three 5-min physiological stress tests (Stroop test, mirror-drawing test and a public speech task) in 721 men and women, aged 58 years, born as term singletons in Amsterdam at about the time of the Dutch 1944-1945 famine. RESULTS: During the stress tests, the systolic blood pressure (SBP) rose from baseline by 20 mmHg during the Stroop test, by 30 mmHg during the mirror-drawing test and by 47 mmHg during the public speech task. The SBP and diastolic blood pressure increase during stress was highest among individuals exposed to famine in early gestation compared with unexposed subjects (4 mmHg extra systolic increase, P = 0.04; 1 mmHg diastolic increase, P = 0.1, both adjusted for sex). Exposure during mid and late gestation was not associated with a stress-related increment of blood pressure (P adjusted for sex > 0.6). Correcting for confounders in a multivariable model did not attenuate the association between famine exposure in early gestation and the SBP increment. The heart rate increment was not related to famine exposure during any part of gestation. CONCLUSION: We found a greater blood pressure increase during stress among individuals exposed to famine in early gestation. Increased stress responsiveness may underlie the known association between coronary heart disease and exposure to famine in early gestation.

Impaired insulin secretion after prenatal exposure to the Dutch famine.

OBJECTIVE: We previously reported that people prenatally exposed to famine during the Dutch Hunger Winter of 1944-1945 have higher 2-h glucose concentrations after an oral glucose tolerance test in later life. We aimed to determine whether this association is mediated through alterations in insulin secretion, insulin sensitivity, or a combination of both. RESEARCH DESIGN AND METHODS: We performed a 15-sample intravenous glucose tolerance test in a subsample of 94 normoglycemic men and women from the Dutch Famine Birth Cohort. We used the disposition index, derived as the product of insulin sensitivity and the first-phase insulin response to glucose as a measure of the activity of the beta-cells adjusted for insulin resistance. In all analyses, we adjusted for sex and BMI. RESULTS: Glucose tolerance was impaired in people who had been prenatally exposed to famine compared with people unexposed to famine (difference in intravenous glucose tolerance test K(g) value -21% [95% CI -41 to -4]). People exposed to famine during midgestation had a significantly lower disposition index (-53% [-126 to -3]) compared with people unexposed to famine. Prenatal exposure to famine during early gestation was also associated with a lower disposition index, but this difference did not reach statistical significance. CONCLUSIONS: Impaired glucose tolerance after exposure to famine during mid-gestation and early gestation seems to be mediated through an insulin secretion defect.

Hypothalamic-pituitary-adrenal axis activity in adults who were prenatally exposed to the Dutch famine.

OBJECTIVE: The hypothalamic-pituitary-adrenal (HPA) axis has been proposed to be susceptible to fetal programming, the process by which an adverse fetal environment elicits permanent physiological and metabolic alterations predisposing to disease in later life. It is hypothesized that fetal exposure to poor circumstances alters the set point of the HPA axis, leading to increased HPA axis activity and subsequent increased cortisol concentrations. In this study, we tested the hypothesis that prenatal exposure to famine during different periods of gestation is associated with increased activity of the HPA axis. DESIGN AND METHODS: We assessed plasma cortisol concentrations after a dexamethasone suppression and an ACTH1-24 -stimulation test in a group of 98 men and women randomly sampled from the Dutch famine birth cohort. Cohort members were born as term singletons around the 1944-1945 Dutch famine. RESULTS: Cortisol profiles after dexamethasone suppression and ACTH1-24 stimulation were similar for participants exposed to famine during late, mid- or early gestation (P = 0.78). Cortisol concentrations after dexamethasone suppression test did not differ between those exposed and those unexposed to famine in utero (mean difference -2% (95% confidence interval (CI) -27 to 23)). Neither peak cortisol concentration (20 nmol/l (95% CI -27 to 66)), cortisol increment (-5 nmol/l (95% CI -56 to 47)) or cortisol area under the curve post-ACTH1-24 injection (4% (95% CI -4 to 12)) differed between exposed and unexposed participants. CONCLUSIONS: Prenatal famine exposure does not seem to affect HPA axis activity at adult age, at least not at the adrenal level. This does not exclude altered HPA axis activity at the levels of the hippocampus and hypothalamus.

Bad experience, good birthing: Dutch low-risk pregnant women with a history of sexual abuse.

OBJECTIVE: The long-term effects on women in childbirth with a history of sexual abuse have only been studied to a limited degree. We estimated the prevalence of lifetime experience among low-risk pregnant women (non-clinical) in The Netherlands as well as the association with (1) psycho-social outcomes, and (2) the birth process. METHODS: Study of 625 randomly selected low-risk pregnant women. At 20-24 weeks gestation, participants completed a questionnaire covering socio-demographic variables, sexual attitude, and psychological determinants. Midwives recorded details of the birth process. RESULTS: Nearly one-in-nine (11.2%) women had experienced sexual abuse. They were on average younger, more likely to smoke, and had lower household income. They reported more conflicting feelings about sex than women who did not report a history of abuse (p = 0.02). Multiparous women with a history of sexual abuse reported more emotional distress (p = 0.037), more internal beliefs concerning health (p = 0.004), and they were also more likely to suffer pelvic pain (p = 0.045). Sexually-abused women reported higher levels of autonomy (p = < 0.001). Referral rates to secondary care were equal. Sexually-abused women were less likely to receive episiotomies (p < 0.005). CONCLUSION: Little difference was observed in major birth-related technical interventions between women with and without a history of sexual abuse.

The effects of the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma2 gene on glucose/insulin metabolism interact with prenatal exposure to famine.

OBJECTIVE: An adverse fetal environment may permanently modify the effects of specific genes on glucose tolerance, insulin secretion, and insulin sensitivity. In the present study, we assessed a possible interaction of the peroxisome proliferator-activated receptor (PPAR)-gamma2 Pro12Ala polymorphism with prenatal exposure to famine on glucose and insulin metabolism. RESEARCH DESIGN AND METHODS: We measured plasma glucose and insulin concentrations after an oral glucose tolerance test and determined the PPAR-gamma2 genotype among 675 term singletons born around the time of the 1944-1945 Dutch famine. RESULTS: A significant interaction effect between exposure to famine during midgestation and the PPAR-gamma2 Pro12Ala polymorphism was found on the prevalence of impaired glucose tolerance and type 2 diabetes. The Ala allele of the PPAR-gamma2 gene was associated with a higher prevalence of impaired glucose tolerance and type 2 diabetes but only in participants who had been prenatally exposed to famine during midgestation. Similar interactions were found for area under the curve for insulin and insulin increment ratio, which were lower for Ala carriers exposed to famine during midgestation. CONCLUSIONS: The effects of the PPAR-gamma2 Pro12Ala polymorphism on glucose and insulin metabolism may be modified by prenatal exposure to famine during midgestation. This is possibly due to a combined deficit in insulin secretion, as conferred by pancreatic beta-cell maldevelopment and carrier type of the Ala allele in the PPAR-gamma2 gene.

Women's opinions on the offer and use of nuchal translucency screening for Down syndrome.

OBJECTIVE: To study the attitude of Dutch women to the offer and subsequent (non)use of nuchal translucency (NT) screening for Down syndrome in the first trimester of pregnancy, in a country where screening is not routinely offered under 36 years of age. METHODS: An experimental NT screening programme offered to pregnant women, together with a series of questionnaires to be completed before and after the offer and (non)use of screening, in 12 midwife practices in three different health districts. PARTICIPANTS: Cohort of pregnant women who had their first prenatal care visit in the participating midwife practices between 1 June 1999 and 1 January 2001. MAIN OUTCOME MEASURES: Women's knowledge and understanding of prenatal screening tests; attitude towards screening offer; perceived freedom of choice; satisfaction with information given; change in attitude over time. RESULTS: Eighty-six percent of women accepted the offer of NT screening. Seventy percent had previous knowledge of NT screening and 92% considered the information given before screening clear and sufficient. Thirty-nine percent of women felt worried to some extent after being given the information, but only 3% would have preferred not to have been informed at all. Ninety percent of women (including 68% of decliners) agree that information on Down syndrome screening should be extended to all pregnant women and feel competent in deciding on screening participation. CONCLUSION: When NT screening is offered as a new screening strategy its concept is understood and well accepted. The large majority of women, including the decliners, are in favour of its standard offer.

Transient hypothyroxinemia in severe hypertensive disorders of pregnancy.

OBJECTIVE: Assess whether and to what extent thyroid function is affected in pregnant women with early and severe hypertensive disorders and in their newborns. METHODS: Patients were 80 women with preeclampsia, hemolysis, elevated liver enzymes, and low platelet count syndrome or gestational hypertension combined with fetal growth restriction in the 24th to 34th week of singleton pregnancies. Maternal thyroid hormone levels and thyroid peroxidase antibodies were determined at admission and 3 months postpartum. Neonatal levels were determined from cord blood at delivery. Maternal hypothyroxinemia was defined as free T(4) (fT(4)) value below 9 pM. RESULTS: At admission 26 (33%) women in the study group had fT(4) levels below 9 pM, with spontaneous normalization during pregnancy. There were no statistically significant differences between thyroid hormone values in women in the study group and 10 normotensive pregnant women in their third trimester. Three months postpartum, 97.5% of patients had normal thyroid hormone levels. Thyroid peroxidase antibodies were elevated in 10% of women postpartum. Their infants, born at a median gestational age of 30 6/7 weeks, had lower cord blood fT(4) and thyroid-stimulating hormone values compared with preterm infants of the comparison group, appropriate for gestational age. Cord blood fT(4) had no correlation with gestational age or maternal fT(4), but there was a significant correlation of cord blood fT(4) with umbilical artery pH. CONCLUSION: Women with severe hypertensive disorders of pregnancy may have transiently lower fT(4) levels, without evidence of a thyroid disorder. Their neonates have lower fT(4) levels at birth unrelated to maternal fT(4), but related to prenatal acidosis. LEVEL OF EVIDENCE: II-2.

Prenatal exposure to the Dutch famine and disease in later life: an overview.

Low birth weight is associated with cardiovascular disease in adulthood. Poor maternal nutrition during gestation contributes to low birth weight. In this paper, we review the findings from a cohort of 2414 people, aged 50 years, born as term singletons around the time of the 1944-1945 Dutch famine, of which 912 people participated in an interview and 741 subjects were also available for hospital examination. We found more coronary heart disease, raised lipids, altered clotting and more obesity after exposure to famine in early gestation compared to those not exposed to the famine. Exposure in mid gestation was associated with obstructive airways disease and microalbuminuria. We found decreased glucose tolerance in people exposed to famine in late gestation. These findings show that maternal undernutrition during gestation has important effects on health in later life, but that the timing of the nutritional insult determines which organ system is affected. Future research should shed more light upon the underlying pathophysiology of the far-reaching effects of prenatal exposure to famine.

Microalbuminuria in adults after prenatal exposure to the Dutch famine.

Maternal undernutrition during gestation is associated with an increase in cardiovascular risk factors in the offspring in adult life. The effect of famine exposure during different stages of gestation on adult microalbuminuria (MA) was studied. MA was measured in 724 people, aged 48 to 53, who were born as term singletons in a university hospital in Amsterdam, the Netherlands, around the time of the Dutch famine 1944 to 1945. Twelve percent of people who were exposed to famine in mid gestation had MA (defined as albumin/creatinine ratio >/=2.5) compared with 7% of those who were not prenatally exposed to famine (odds ratio 2.1; 95% confidence interval 1.0 to 4.3). Correcting for BP, diabetes, and other influences that affect MA did not attenuate this association (adjusted odds ratio 3.2; 95% confidence interval 1.4 to 7.7). The effect of famine was independent of size at birth. Midgestation is a period of rapid increase in nephron number, which is critical in determining nephron endowment at birth. Fetal undernutrition may lead to lower nephron endowment with consequent MA in adult life.

Abnormal development of the vasculosyncytial membrane in early pregnancy failure.

OBJECTIVE: To investigate chorionic villous vasculogenesis (maturation) and development of the vasculosyncytial membrane (margination) using CD34 immunohistochemistry. DESIGN: Case-control study. SETTING: Microscopic analysis of first trimester chorionic villi. PATIENT(S): Twelve patients with anembryonic pregnancies, 12 with embryonic death, and 12 with terminated normal pregnancies. INTERVENTION(S): Quantitative analysis of chorionic villi blinded to group and gestational age using CD34 immunohistochemistry. MAIN OUTCOME MEASURE(S): Vascular parameters (mean functional vascular area, vessels with a lumen, and hemangiogenetic cords, peripherally or centrally located). RESULT(S): Terminated normal pregnancies show significantly more vessels per chorionic villus (maturation) (mean +/- SEM) in comparison with embryonic deaths and anembryonic pregnancies (5.3 +/- 0.3 vs. 1.4 +/- 0.2 and 0.7 +/- 0.1), located mainly peripherally (margination) (3.0 +/- 0.2 vs. 0.9 +/- 0.2 and 0.2 +/- 0.0). Anembryonic pregnancies show significantly more centrally located cords in comparison with embryonic deaths and termination of pregnancies (3.3 +/- 0.2 vs. 2.7 +/- 0.2 and 1.5 +/- 0.1). CONCLUSION(S): A defective chorionic villous vascularization, demonstrating inadequate vasculogenesis and abnormal development of the vasculosyncytial membrane, is seen in pregnancies complicated by embryonic death and is even more pronounced in anembryonic pregnancies. Initiation of placental vasculogenesis is a basic feature in all types of pregnancy and is subsequently modulated directly or indirectly by embryonic signaling.

Effectiveness of detection of intrauterine growth retardation by abdominal palpation as screening test in a low risk population: an observational study.

OBJECTIVE: To evaluate the performance of abdominal palpation as a screening test for intrauterine growth retardation (IUGR) in a low risk population, under standard practice conditions. STUDY DESIGN: Population based observational study of 6318 consecutive low risk singleton pregnancies. The Dutch obstetric system distinguishes low from high risk pregnancies. In the low risk group abdominal palpation as a screening test is performed by midwives. If a complication, like IUGR, during prenatal care is assessed, the women is referred to a consulted obstetrician. Ultrasound is performed by the consulted obstetrician. In case of sustained suspicion the women is selected as high risk. OUTCOME PARAMETERS: severe small for gestational age (SGA) birthweight below 2.3rd centile, all SGA birthweight below 10th centile, operative delivery, neonatal morbidity and perinatal mortality. Screening value of abdominal palpation, abdominal palpation combined with ultrasound, and the performance of high risk selection was assessed by conventional performance measures. RESULTS: Abdominal palpation as a screening test for IUGR is of limited value: the observed sensitivities were 28% for severe SGA and 21% for SGA p < or = 10, respectively. After ultrasound in case of sustained suspicion, the sensitivity in detection of severe SGA was 25% and positive predictive value (PPV) 16%. In detection of SGA p < or = 10 sensitivity was 15% and PPV 55%, which means 45% were false positives. The sensitivity of the Dutch obstetric system in selection of high risk pregnancies in detection of severe SGA was 53%, in detection of SGA p < or = 10 was 37%. Perinatal mortality was 0.9% (57/6318) and 32% of these cases were SGA. Six cases of fetal death were unrecognised during prenatal care (0.09%) and seem preventable. The prevalence of a 5 min Apgar Score < or = 7 was significantly higher in the SGA infants if SGA was defined as p < or = 10. CONCLUSIONS: The diagnostic performance of abdominal palpation as a screening test for IUGR detection in a low risk population is disappointing. However, various stratagems such as routine ultrasound do not improve detection rate or perinatal morbidity and mortality.

Postpartum haemorrhage in nulliparous women: incidence and risk factors in low and high risk women. A Dutch population-based cohort study on standard (> or = 500 ml) and severe (> or = 1000 ml) postpartum haemorrhage.

OBJECTIVE: To determine the incidence and risk factors for standard and severe postpartum haemorrhage (PPH) in vaginally delivering nulliparous women, before and after risk stratification. STUDY DESIGN: A population-based cohort study in an unselected cohort nulliparous women (N = 3464) in 'The Zaanstreek' district, The Netherlands. Risk stratification is part of routine care, where midwives cover all obstetrical care for women with low risk pregnancies. RESULTS: The incidence of standard PPH (> or = 500 ml) and severe PPH (> or = 1000 ml) were 19 and 4.2%, respectively. A retained placenta occurred in 1.8%. These data show consistently slightly higher values as compared to studies in literature. The most important risk factors for standard and severe PPH were related to an abnormal third stage of labour-third stage > or = 30 min and retained placenta (in severe PPH: odds ratio (OR) 14.1, 95% confidence interval (CI) 10.4-19.1). High birth weight and perineal damage were less important, but independent, significant risk factors. In the low risk group (N = 1416), incidence of severe PPH was 4.0%. Independent risk factors for severe PPH were third stage > or = 30 min (incidence 7.1%, OR 3.6) and retained placenta (incidence 1.2%, OR 21.6). In 25% of the women with a prolonged third stage (> or = 30 min), third stage was complicated due to retained placenta and/or severe PPH (1.8% of the low risk group). CONCLUSIONS: The incidence of PPH in nulliparous women in this cohort was on average higher than published data, while the most important risk factors for standard and severe PPH, even after risk stratification, were the same. A prolonged third stage of labour has to be considered as abnormal, requiring specific action.