607: Maternal obesity and perinatal mortality risk

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by population based centiles demonstrated a downward trend as BMI increased, with the lowest SGA rate being in the highest BMI category. CONCLUSION: The elevated stillbirth risk in pregnancies of obese mothers is associated with an increase in customised SGA rate. This link is hidden when population based centiles are used, but becomes apparent when birthweight is measured against the customised growth potential, thus helping to identify the presence of fetal growth restriction.

0002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.468 0002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.470

604 The July phenomenon: does it apply to obstetrics? 606 Clinical causes of stillbirth associated with maternal obesity

Amanda Yeaton-Massey1, Yvonne Cheng1, Stephanie Handler1, Jesus Granados1, Aaron Caughey1 1

University of California, San Francisco, San Francisco, California

OBJECTIVE: Evaluate the incidence of maternal and neonatal compli-

cations for preterm births at teaching hospitals in California during the month of July. STUDY DESIGN: This is a retrospective cohort study of maternal and neonatal outcomes for preterm deliveries at obstetric teaching hospitals in California during the month of July versus the remainder of the year. The incidence of chorioamnionitis, maternal sepsis, post-partum hemorrhage, shoulder dystocia, neonatal asphyxia and neonatal death were examined using bivariate analysis. RESULTS: Rates of adverse outcomes were the same during the month of July for all of our outcomes of interest including maternal sepsis, post-partum hemorrhage, neonatal asphyxia and neonatal death. Notably, the rate of maternal sepsis was zero during the month of July. CONCLUSION: While there are data to support the existence of a ‘July phenomenon’ in other areas of medicine our data support the assertion that this does not hold true in obstetrics. This may be related to the close supervision of residents by attending obstetricians in teaching hospitals. 0002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.469

Jason Gardosi1, Mandy Williams1, Andre Francis1 1

West Midlands Perinatal Institute, Birmingham, United Kingdom

OBJECTIVE: We wanted to examine the effect of maternal obesity on

the risk of stillbirth, applying a new method to categorise the causes of stillbirth. STUDY DESIGN: The cohort consisted of 48,357 consecutive, unselected births from 6 maternity units during 2006/7, including 328 stillbirths from 24.0 weeks. Maternal BMI categories were defined as ⬍20, 2024.9, 25-29.9, 30-34.9, 35⫹. The clinical classification of ReCoDe (relevant condition at death, BMJ 2005) was used to classify the stillbirths and divide them into three main categories: congenital anomalies (Cong Anom; 18%), fetal growth restriction (FGR - defined as ⬍10th customised centile: 43%) and a miscellaneous group which included maternal, placental, umbilical cord and intrapartum related conditions (Misc, 39%). RESULTS: Mothers with BMI ⬍20 had a lower risk of stillbirth, while obese mothers had an elevated risk from BMI 30 upwards. Analysis within subgroups showed that the association with BMI was significant only for stillbirths with fetal growth restriction (Table). CONCLUSION: Obese mothers have an increased risk of stillbirth due to fetal growth restriction.

605 Stillbirth in pregnancies of obese mothers is associated with increased risk of fetal growth restriction Jason Gardosi1, Mandy Williams1, Andre Francis1 1


OBJECTIVE: We wanted to assess the risk of stillbirth in different BMI

categories, and study their association with the rate of small for gestational age (SGA) babies. STUDY DESIGN: 48,357 consecutive births during 2006/7 from 6 maternity units in the West Midlands. Rates of SGA at birth were assessed by two methods: SGA based on the local weight for gestational age standard (’population SGA’), or ’customised SGA’ based on the fetal growth potential. RESULTS: 10.5% of mothers had a BMI ⬍20, and 21% were 30 or over, incuding 7.8% with a BMI of 35⫹. Stillbirth rates (per 1000) rose incrementally from low to high BMI categories: BMI⬍20: 2.8; 2024.9: 6.2; 25-29.9: 7.6, 30-34.9: 8.5, and 35⫹: 9.8. SGA rates based on the customised fetal growth potential in the 5 BMI groups were 18.5, 15.9, 17.1, 18.8 and 22.0, respectively, and appeared to follow the increasing stillbirth rate. However in the BMI⬍20 group, the SGA rate was higher despite a lower risk of stillbirth. In contrast, the rate of SGA

0002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.471

607 Maternal obesity and perinatal mortality risk Andre Francis1, Mandy Williams1, Jason Gardosi1 1


OBJECTIVE: We aimed to quantify the association between maternal

body mass index and perinatal mortality rate, looking separately at stillbirths and early neonatal deaths. STUDY DESIGN: The cohort consisted of 48,357 consecutive births during 2006/7 from 6 maternity units in the West Midlands, including 328 stillbirths (from 24.0 weeks) and 240 early neonatal deaths (⬍7 days). Maternal BMI categories were defined as ⬍20, 20-24.9, 25-29.9, 30-34.9, and 35⫹. The latter two groups were amalgamated for neonatal deaths because of small numbers.

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RESULTS: Stillbirth rate increased from 6.2/1000 in the reference BMI range (20-24.9) to 7.6 (25-29.9), 8.5 (30-34.9), and 9.8 (35⫹). The elevated mortality rate was significant for BMI 30-34.9 (OR 1.4, CI 1.04-2.0) and BMI 35⫹ (OR 1.6, CI 1.1 – 2.3). Mothers with low BMI (⬍20) had a significantly reduced rate of stillbirth: 2.8/1000 (OR 0.5, CI 0.3-0.8). In contrast, early neonatal deaths had no such association, with rates ranging from 4.5, 4.6, 5.6, and 5.3/1000 from lowest to highest BMI category. CONCLUSION: High perinatal mortality associated with obesity is mainly due to an increased rate of stillbirths rather than neonatal deaths. The stillbirth rate of lean mothers is significantly lower than that of mothers with normal BMI.


www.AJOG.org 609 Intrapartum stillbirth and fetal growth restriction Abdel Elsheikh1, Andre Francis1, Jason Gardosi1 1


OBJECTIVE: To investigate the causes of intrapartum stillbirths, which

in our population have essentially remained unchanged over the last decade. STUDY DESIGN: The database consisted of 789,383 births in the West Midlands over the period 1997-2008, and included 3808 normally formed stillbirths from 24.0 weeks. The clinical ReCoDe classification was applied to determine the relevant condition at death. FGR was defined according to growth potential, as below the 10th customised birthweight-for-gestational age percentile. RESULTS: 437 of the stillbirths (11.3%) occurred intrapartum. The gestational age distribution was bimodal, and included 33.4% of deaths at ⬍28 weeks and 41.2 % at 37⫹ weeks. 176 (40.3%) of deaths were classified as ‘intrapartum asphyxia’, 152 (34.8%) as abruptio or other placental causes, 48 (11%) as cord accidents, 26 (5.9%) with pre-eclampsia and 33 (7.6%) with miscellaneous causes. However 143 of all intrapartum deaths (32.7%) had fetal growth restriction, and by ReCoDe this became the single largest category. 34.1% of all deaths due to asphyxia and 30.3% of deaths due to abruptio placentae were preceded by intrauterine growth restriction. CONCLUSION: The results suggest that many intrapartum deaths involve growth restricted babies. Better antepartum recognition of growth failure is likely to lead to increased vigilance and prevention of fetal compromise during labour. 0002-9378/$ – see front matter • doi:10.1016/j.ajog.2009.10.474

608 Perinatal asphyxia: does obstetric volume matter? Aaron Caughey1, Brian Shaffer2, Sinae Nakagawa2, James Nicholson3, Yvonne Cheng1 1

University of California, San Francisco, San Francisco, California, University of California, San Francisco, California, 3University of Pennsylvania, Philadelphia, Pennsylvania 2

OBJECTIVE: To examine the association between the annual number of

births performed by hospitals and perinatal outcomes. STUDY DESIGN: This is a retrospective cohort study of all births delivered in California in 2006 using Birth and Death Certificate files linked with the California Patient Discharge Data. The annual number of births performed by hospital was examined as a predictor of perinatal outcomes using chi-square tests and multivariable logistic regression analyses. RESULTS: The risk of birth asphyxia was increased in hospitals that performed between 100-2499 births annually while this risk was decreased in hospitals with ⱖ4000 births per year (Table). CONCLUSION: The findings from this descriptive study deserve further attention at the individual hospital level. In particular, characteristics of providers, practice style, staffing all need to be examined to determine whether they contribute. Meanwhile, providers should be aware of the potential risks in lower volume hospitals.


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610 Home delivery in low risk women reduces the number of caesarean sections without affecting perinatal outcome Birgit Van der Goes1, Anita Ravelli2, Ank De Jonge3, Trees Wiegers4, Simone Buitendijk5, Jan Nijhuis6, Ben Willem Mol7 1 Academisch Medisch Centrum Amsterdam, Obstetrics and gynaecology, Amsterdam, Noord-Holland, Netherlands, 2Academisch Medisch Centrum Amsterdam, Amsterdam, Netherlands, 3VU medisch centrum, Amsterdam, Noord-Holland, Netherlands, 4Nederlands Instituut voor onderzoek van de gezondheidszorg (NIVEL), Utrecht, Netherlands, 5TNO Quality of Life, Leiden, Zuid-Holland, Netherlands, 6Maastricht University Medical Centre, Maastricht, Limburg, Netherlands, 7Academic Medical Centre, Amsterdam, Obstetrics and Gynecology, Netherlands

OBJECTIVE: Worldwide, there is a strong increase in the number of

Caesarean sections. This increase is worrisome, as it is generating morbidity without an improvement in perinatal outcome. One reason for the increased C section rate might be the immediate presence of gynaecologists in hospital, who are used to intervene irrespective of the a priori risk. STUDY DESIGN: We performed a retrospective nationwide cohort study among 488,568 low risk women delivering under primary midwife-led care in The Netherlands over aperiod of 7 years (2000-2006). In The Netherlands, low risk women deliver under primary responsibility of a midwife, who has the possibility to refer to a gynaecologist for fetal distress, non-progressive labour or the need for pain relief. These low risk women have the choice between a planned home delivery and a planned hospital delivery, both under supervision of an independent working midwife. Caesarean section was the primary outcome. Analysis was according to intention-to-treat: the planned place of birth at home or in hospital. RESULTS: The Caesarean section rate was 5,973 among 321,307 women (1.9%) in the home delivery group versus 4,348 among 163,261 women (2.7%) starting in hospital (RR .70, 95% confidence interval .67 to .73). Similarly, the vaginal assisted delivery rates were 7.1% (22,698/321,307) in the home delivery group and 8.4% (13,707/ 163,261) in the hospital group (RR .84, 95% confidence interval .82 to .86). There was no difference in perinatal outcome in the two groups.

American Journal of Obstetrics & Gynecology Supplement to DECEMBER 2009