Jelle Schaaf

Trends in preterm birth: singleton and multiple pregnancies in the Netherlands, 2000–2007

Please cite this paper as: Schaaf J, Mol B, Abu‐Hanna A, Ravelli A. Trends in preterm birth: singleton and multiple pregnancies in the Netherlands, 2000–2007. BJOG 2011; DOI: 10.1111/j.1471‐0528.2011.03010.x.

Term breech deliveries in the Netherlands: did the increased cesarean rate affect neonatal outcome? A population‐based cohort study

The aim of this study was to evaluate the effect of the increased cesarean rate for term breech presentation on neonatal outcome. We also investigated whether the clinical case selection for vaginal delivery applied by Dutch obstetricians led to an optimization of neonatal outcome, or whether there is still room for improvement in terms of perinatal outcome.

Ethnic and racial disparities in the risk of preterm birth: a systematic review and meta-analysis.

OBJECTIVES The aim of this study is to present a systematic review of available literature on the effect of maternal ethnicity (Africans/blacks, Asians, Hispanics, others) on the risk of preterm birth (PTB). STUDY DESIGN Studies investigating ethnicity (or race) as a risk factor for PTB were included if performing adjustments for confounders. A meta-analysis was performed, and data were synthesized using a random effects model. RESULTS Forty-five studies met the inclusion criteria. Black ethnicity was associated with an increased risk of PTB when compared with whites (range of adjusted odds ratios [ORs] 0.6 to 2.8, pooled OR 2.0; 95% confidence interval [CI] 1.8 to 2.2). For Asian ethnicity, there was no significant association (range of adjusted ORs 0.6 to 2.3). For Hispanic ethnicity, there also was no significant association (range of adjusted ORs 0.7 to 1.5). CONCLUSIONS Ethnic disparities in the risk of PTB were clearly pronounced among black women. Future research should focus on preventative strategies for ethnic groups at high risk for PTB. Information on ethnic disparities in risk of PTB-related neonatal morbidity and mortality is lacking and is also a topic of interest for future research.

Vaginal delivery versus caesarean section in preterm breech delivery: a systematic review

There is controversy on the preferred mode of delivery (vaginal delivery (VD) versus caesarean section (CS)) in preterm breech delivery in relation to neonatal outcome. While CS is supposed to be safer for the fetus, arguments against CS can be the increased risk of maternal morbidity, risks for future pregnancies, and costs. Moreover, neonatal respiratory distress syndrome occurs more frequently after CS compared to VD. In the past, several RCTs have been started on this subject, but they were all preliminary and stopped due to recruitment difficulties. As the Cochrane review of these RCTs reported on 116 women only, knowledge on the effectiveness of CS and VD can at present only be obtained from non-randomized studies. We performed a systematic review and meta-analysis of non-randomized studies that assessed the association between mode of delivery and neonatal mortality in women with preterm breech presentation. We searched Pubmed, Embase and the Cochrane library for articles comparing neonatal mortality after VD versus CS in preterm breech presentation (gestational age 25(+0) till 36(+6) weeks). Seven studies, involving a total of 3557 women, met the eligibility criteria and were included in this systematic review. The weighted risk of neonatal mortality was 3.8% in the CS group and 11.5% in the VD group (pooled RR 0.63 (95% CI 0.48-0.81)). We conclude that cohort studies indicate that CS reduces neonatal mortality as compared to VD.

Recurrence risk of preterm birth in subsequent twin pregnancy after preterm singleton delivery

Please cite this paper as: Schaaf J, Hof M, Mol B, Abu‐Hanna A, Ravelli A. Recurrence risk of preterm birth in subsequent twin pregnancy after preterm singleton delivery.BJOG 2012;119:1624–1629.

Development of a prognostic model for predicting spontaneous singleton preterm birth

OBJECTIVE To develop and validate a prognostic model for prediction of spontaneous preterm birth. STUDY DESIGN Prospective cohort study using data of the nationwide perinatal registry in The Netherlands. We studied 1,524,058 singleton pregnancies between 1999 and 2007. We developed a multiple logistic regression model to estimate the risk of spontaneous preterm birth based on maternal and pregnancy characteristics. We used bootstrapping techniques to internally validate our model. Discrimination (AUC), accuracy (Brier score) and calibration (calibration graphs and Hosmer-Lemeshow C-statistic) were used to assess the models predictive performance. Our primary outcome measure was spontaneous preterm birth at <37 completed weeks. RESULTS Spontaneous preterm birth occurred in 57,796 (3.8%) pregnancies. The final model included 13 variables for predicting preterm birth. The predicted probabilities ranged from 0.01 to 0.71 (IQR 0.02-0.04). The model had an area under the receiver operator characteristic curve (AUC) of 0.63 (95% CI 0.63-0.63), the Brier score was 0.04 (95% CI 0.04-0.04) and the Hosmer Lemeshow C-statistic was significant (p<0.0001). The calibration graph showed overprediction at higher values of predicted probability. The positive predictive value was 26% (95% CI 20-33%) for the 0.4 probability cut-off point. CONCLUSIONS The models discrimination was fair and it had modest calibration. Previous preterm birth, drug abuse and vaginal bleeding in the first half of pregnancy were the most important predictors for spontaneous preterm birth. Although not applicable in clinical practice yet, this model is a next step towards early prediction of spontaneous preterm birth that enables caregivers to start preventive therapy in women at higher risk.

Ethnic disparities in the risk of adverse neonatal outcome after spontaneous preterm birth

Objective. To describe ethnic disparities in the risk of spontaneous preterm birth and related adverse neonatal outcome. Design. Nationwide prospective cohort study. Setting. The Netherlands, 1999–2007. Population. Nine hundred and sixty‐nine thousand, four hundred and ninety‐one singleton pregnancies with a spontaneous onset of labor. Methods. We investigated ethnic disparities in perinatal outcome for European white, African, South‐Asian, Mediterranean and East‐Asian women. We performed multivariate logistic regression analyses to calculate the adjusted odds ratio (aOR) and confidence intervals (CIs) of spontaneous preterm birth and the risk of subsequent neonatal morbidity and mortality. Main outcome measures. The primary outcome measure was spontaneous preterm birth before 37 completed weeks of gestation. Secondarily, we investigated subsequent adverse neonatal outcome, which was a composite outcome of intraventricular hemorrhage, bronchopulmonary dysplasia, infant respiratory distress syndrome, neonatal sepsis or neonatal mortality within 28 days after birth. Results. Compared with European whites, the aOR of delivering preterm was 1.33 (95% CI 1.26–1.41) for African women, 1.58 (95% CI 1.47–1.69) for South‐Asians, 0.88 (95% CI 0.84–0.91) for Mediterraneans and 1.04 (95% CI 0.98–1.11) for East‐Asians. Subsequent odds of adverse neonatal outcome were significantly lower for African (aOR 0.51; 95% CI 0.41–0.64) and Mediterranean women (aOR 0.86; 95% CI 0.75–0.99) when compared with European whites. Conclusions. African and South‐Asian women are at higher risk for preterm birth than European white women. However, the harmful effect of preterm birth on neonatal outcome is less severe for these women.

Reproductive outcome after early-onset pre-eclampsia

BACKGROUND Early-onset pre-eclampsia is an important cause of maternal and neonatal morbidity and mortality and is believed to have a significant impact on future maternal physical and psychological health. However, structured follow-up data of women with a history of early-onset pre-eclampsia are lacking. This study aims to present comprehensive data of a large cohort of women with a history of early-onset pre-eclampsia with respect to future reproductive health, family planning and subsequent pregnancy rates. METHODS A tertiary referral cohort of 304 women entered the follow-up study at 6-12 months after their first delivery. Detailed data on maternal and neonatal outcomes, family planning and subsequent pregnancies were recorded. In addition, data on perspectives, major concerns and decision-making of women who had not achieved a second pregnancy were collected by questionnaire and structured interviews. Data were compared with a population of 268 low-risk primiparous women with an uncomplicated delivery. RESULTS At a mean of 5.5 years after first delivery, 65.8% of women with a history of early-onset pre-eclampsia had achieved a second pregnancy compared with 77.6% of healthy controls. At follow-up, 19.1% of women with a history of early-onset pre-eclampsia had an active wish to become pregnant, whereas 15.1% of women did not wish to achieve a future pregnancy. In the latter group, decision-making was most commonly influenced by fear of recurrent disease (33%) and fear of delivering another premature child (33%) among others reasons, e.g. post-partum counseling and concerns of the partner. CONCLUSIONS The majority of women with a history of early-onset pre-eclampsia achieve or wish to achieve a second pregnancy within a few years of their delivery. Nonetheless, first pregnancy early-onset pre-eclampsia appears to have a significant impact on future reproductive health and decision-making, emphasizing the importance of careful post-partum counseling.

Ethnic disparities in perinatal mortality at 40 and 41 weeks of gestation

Abstract Objective: To evaluate whether maternal ethnicity affects perinatal mortality by week of gestation from 39 weeks onwards. Study design: In this cohort study, we used data from the nationwide Netherlands Perinatal Registry from 1999 until 2008. All singleton infants born between 39+0 and 42+6 weeks of gestation without congenital anomalies were included. We used crude and multivariate logistic regression analyses with white Europeans as the reference to calculate the adjusted odds ratios (aOR) of South Asian, African and Mediterranean women. The main outcome measure was perinatal mortality (antepartum and intrapartum/neonatal mortality within 7 days after birth). Results: We studied 1,092,255 singleton deliveries. Perinatal mortality occurred in 2315 infants (2.1‰). There was interaction between gestational age and ethnicity (P<0.0001). In week 40 (40+0–40+6) South Asian (aOR 1.9; 95% CI 1.1–3.4) and Mediterranean (aOR 1.3; 95% CI 1.04–1.7) women had an increased risk of perinatal mortality. The perinatal mortality risk became greater in week 41 for South Asian (aOR 4.5 95% CI 2.8–7.2), African (aOR 2.2; 95%CI 1.4–3.4) and Mediterranean (aOR 2.2; 95% CI 1.8–2.9) women, especially among small for gestational age infants. Conclusion: With increasing gestational age beyond 39 weeks, perinatal mortality risk increases more strongly among South Asian, African and Mediterranean women compared to European whites.

Follow-up of prolapse surgery in rural Nepal

Pelvic organ prolapse (POP) is a significant problem in Nepal. Surgical treatment is scarcely available and little is known of the results of POP surgery on women living under burdensome circumstances. The aim of our study was to set up a follow-up program in rural Nepal and evaluate POP surgery. In 2004 and 2006, 74 women with a POP from remote areas around Dhulikhel Hospital underwent prolapse surgery. Together with local contacts men, a plan was made to implement a follow-up program. All the operated patients were invited to a follow-up visit in March 2007. Thirty-three (45%) patients attended the follow-up: 85% (n = 28) found the effect of the procedure an improvement. A satisfactory anatomic outcome was found in 93% (n = 32). A remarkable finding was the reduction in physical labour after the surgical procedure in 50% of the follow-up cases. Some adjustments in the follow-up program may contribute to a higher participation.