Elaine Fyfe

Risk of First-Stage and Second-Stage Cesarean Delivery by Maternal Body Mass Index Among Nulliparous Women in Labor at Term

OBJECTIVE: To estimate in a cohort of nulliparous women in labor at term whether cesarean delivery rates are increased in first and second stages of labor in overweight and obese women and whether being overweight or obese is an independent risk factor for cesarean delivery. METHODS: Nulliparous women recruited to the prospective Screening for Pregnancy Endpoints study who went into labor after 37 weeks of gestation were categorized according to ethnicity-specific body mass index (BMI) criteria as normal, overweight, or obese. Normal BMI was the referent. Multivariable analysis, adjusting for known confounders for obesity and cesarean delivery, was performed to estimate if being overweight or obese was associated with an increased risk of cesarean in labor (all cesarean deliveries and in first stage of labor). RESULTS: Of 2,629 participants, 1,416 (54%) had normal BMIs, 773 (29%) were overweight, and 440 (17%) were obese. First-stage cesarean delivery was increased in overweight (n=149 [19%]) and obese (n=137 [31%]) women compared with normal-weight women (n=181 [13%; P<.001), whereas second-stage cesarean delivery was similar (normal BMI 76 [6.2%], overweight 45 [7.2%], obese 23 [7.6%], P=.87). Being overweight or obese was an independent risk factor for all cesarean deliveries in labor with adjusted odds ratio (OR) of 1.34 (95% confidence interval [CI] 1.07–1.67) and 2.51 (95% CI 1.94–3.25), respectively. Similarly, being overweight (adjusted OR 1.39; 95% CI 1.09–1.79) or obese (adjusted OR 2.89; 95% CI 2.19–3.80) was associated with increased cesarean delivery during the first stage. Risks of cesarean delivery were similar regardless of whether ethnicity-specific or World Health Organization (WHO) BMI criteria were used. CONCLUSION: Among nulliparous women in labor at term, being overweight or obese by either WHO or ethnicity-specific BMI criteria is an independent risk factor for cesarean delivery in the first stage but not the second stage of labor. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, www.anzctr.org.au, ACTRN12607000551493. LEVEL OF EVIDENCE: II

Maternal obesity and postpartum haemorrhage after vaginal and caesarean delivery among nulliparous women at term: a retrospective cohort study

BackgroundIncreasing rates of postpartum haemorrhage in developed countries over the past two decades are not explained by corresponding changes in risk factors and conjecture has been raised that maternal obesity may be responsible. Few studies investigating risk factors for PPH have included BMI or investigated PPH risk among nulliparous women. The aim of this study was to determine in a cohort of nulliparous women delivering at term whether overweight and obesity are independent risk factors for major postpartum haemorrhage (PPH ≥1000ml) after vaginal and caesarean section delivery.MethodsThe study population was nulliparous singleton pregnancies delivered at term at National Women’s Hospital, Auckland, New Zealand from 2006 to 2009 (N=11,363). Multivariable logistic regression was adjusted for risk factors for major PPH.ResultsThere were 7238 (63.7%) women of normal BMI, 2631 (23.2%) overweight and 1494 (13.1%) obese. Overall, PPH rates were increased in overweight and obese compared with normal-weight women (n=255 [9.7%], n=233 [15.6%]), n=524 [7.2%], p <.001) respectively. There was an approximate twofold increase in risk in obese nulliparous women that was independent of confounders, adjusted odds ratio [aOR (95% CI)] for all deliveries 1.86 (1.51-2.28). Being obese was a risk factor for major PPH following both caesarean 1.73 (1.32-2.28) and vaginal delivery 2.11 (1.54-2.89) and the latter risk was similar after exclusion of women with major perineal trauma and retained placentae. Three additional factors were consistently associated with risk for major PPH regardless of mode of delivery: increasing infant birthweight, antepartum haemorrhage and Asian ethnicity.ConclusionNulliparous obese women have a twofold increase in risk of major PPH compared to women with normal BMI regardless of mode of delivery. Higher rates of PPH among obese women are not attributable to their higher rates of caesarean delivery. Obesity is an important high risk factor for PPH, and the risk following vaginal delivery is emphasised. We recommend in addition to standard practice of active management of third stage of labour, there should be increased vigilance and preparation for PPH management in obese women.

Independent risk factors for infants who are small for gestational age by customised birthweight centiles in a multi-ethnic New Zealand population

Infants born small for gestational age (SGA) by customised birthweight centiles are at increased risk of adverse outcomes compared with those SGA by population centiles. Risk factors for customised SGA have not previously been described in a general obstetric population.

Partner violence prevalence among women attending a Maori health provider clinic

Objective: To determine partner violence rates among women attending a general practice in Aotearoa, New Zealand.

The impact of maternal body mass index on the phenotype of pre-eclampsia: a prospective cohort study

Please cite this paper as: Anderson N, McCowan L, Fyfe E, Chan E, Taylor R, Stewart A, Dekker G, North R, on behalf of the SCOPE Consortium. The impact of maternal body mass index on the phenotype of pre‐eclampsia: a prospective cohort study. BJOG 2012;119:589–595.

Ethnicity, body mass index and risk of pre-eclampsia in a multiethnic New Zealand population

Pre‐eclampsia rates are reported to vary by ethnicity; however, few studies include body mass index (BMI). Increasing BMI has a dose‐dependent relationship with pre‐eclampsia, and rates of overweight and obesity as well as ratios of body fat to muscle mass differ between ethnicities. We hypothesised that after adjusting for confounders, including ethnic‐specific BMI, ethnicity would not be an independent risk factor for pre‐eclampsia.

Clinical and biochemical factors associated with preeclampsia in women with obesity

To compare early pregnancy clinical and biomarker risk factors for later development of preeclampsia between women with obesity (body mass index, BMI ≥30 kg/m2) and those with a normal BMI (20–25 kg/m2).

Ethnicity and risk of caesarean section in a term, nulliparous New Zealand obstetric cohort

One in four New Zealand (NZ) women undergo caesarean section (CS); however, little is understood about how ethnicity influences CS rates. Previous NZ studies do not include many of NZs ethnic groups and have been unable to account comprehensively for clinical risk factors.

Elevated maternal lipids in early pregnancy are not associated with risk of intrapartum caesarean in overweight and obese nulliparous women

BackgroundMaternal overweight and obesity are associated with slower labour progress and increased caesarean delivery for failure to progress. Obesity is also associated with hyperlipidaemia and cholesterol inhibits myometrial contractility in vitro. Our aim was, among overweight and obese nulliparous women, to investigate 1. the role of early pregnancy serum cholesterol and 2. clinical risk factors associated with first stage caesarean for failure to progress at term.MethodsSecondary data analysis from a prospective cohort of overweight/obese New Zealand and Australian nullipara recruited to the SCOPE study. Women who laboured at term and delivered vaginally (n=840) or required first stage caesarean for failure to progress (n=196) were included. Maternal characteristics and serum cholesterol at 14–16 weeks’ of gestation were compared according to delivery mode in univariable and multivariable analyses (adjusted for BMI, maternal age and height, obstetric care type, induction of labour and gestation at delivery ≥41 weeks).ResultsTotal cholesterol at 14–16 weeks was not higher among women requiring first stage caesarean for failure to progress compared to those with vaginal delivery (5.55 ± 0.92 versus 5.67 ± 0.85 mmol/L, p= 0.10 respectively). Antenatal risk factors for first stage caesarean for failure to progress in overweight and obese women were BMI (adjusted odds ratio [aOR (95% CI)] 1.15 (1.07-1.22) per 5 unit increase, maternal age 1.37 (1.17-1.61) per 5 year increase, height 1.09 (1.06-1.12) per 1cm reduction), induction of labour 1.94 (1.38-2.73) and prolonged pregnancy ≥41 weeks 1.64 (1.14-2.35).ConclusionsElevated maternal cholesterol in early pregnancy is not a risk factor for first stage caesarean for failure to progress in overweight/obese women. Other clinically relevant risk factors identified are: increasing maternal BMI, increasing maternal age, induction of labour and prolonged pregnancy ≥41 weeks’ of gestation.

Clinical, ultrasound and molecular biomarkers for early prediction of large for gestational age infants in nulliparous women: An international prospective cohort study.

Objective To develop a prediction model for term infants born large for gestational age (LGA) by customised birthweight centiles. Methods International prospective cohort of nulliparous women with singleton pregnancy recruited to the Screening for Pregnancy Endpoints (SCOPE) study. LGA was defined as birthweight above the 90th customised centile, including adjustment for parity, ethnicity, maternal height and weight, fetal gender and gestational age. Clinical risk factors, ultrasound parameters and biomarkers at 14–16 or 19–21 weeks were combined into a prediction model for LGA infants at term using stepwise logistic regression in a training dataset. Prediction performance was assessed in a validation dataset using area under the Receiver Operating Characteristics curve (AUC) and detection rate at fixed false positive rates. Results The prevalence of LGA at term was 8.8% (n = 491/5628). Clinical and ultrasound factors selected in the prediction model for LGA infants were maternal birthweight, gestational weight gain between 14–16 and 19–21 weeks, and fetal abdominal circumference, head circumference and uterine artery Doppler resistance index at 19–21 weeks (AUC 0.67; 95%CI 0.63–0.71). Sensitivity of this model was 24% and 49% for a fixed false positive rate of 10% and 25%, respectively. The addition of biomarkers resulted in selection of random glucose, LDL-cholesterol, vascular endothelial growth factor receptor-1 (VEGFR1) and neutrophil gelatinase-associated lipocalin (NGAL), but with minimal improvement in model performance (AUC 0.69; 95%CI 0.65–0.73). Sensitivity of the full model was 26% and 50% for a fixed false positive rate of 10% and 25%, respectively. Conclusion Prediction of LGA infants at term has limited diagnostic performance before 22 weeks but may have a role in contingency screening in later pregnancy.