Rhona Mahony

Low glycaemic index diet in pregnancy to prevent macrosomia (ROLO study): randomised control trial

Objective To determine if a low glycaemic index diet in pregnancy could reduce the incidence of macrosomia in an at risk group. Design Randomised controlled trial. Setting Maternity hospital in Dublin, Ireland. Participants 800 women without diabetes, all in their second pregnancy between January 2007 to January 2011, having previously delivered an infant weighing greater than 4 kg. Intervention Women were randomised to receive no dietary intervention or start on a low glycaemic index diet from early pregnancy. Main outcomes The primary outcome measure was difference in birth weight. The secondary outcome measure was difference in gestational weight gain. Results No significant difference was seen between the two groups in absolute birth weight, birthweight centile, or ponderal index. Significantly less gestational weight gain occurred in women in the intervention arm (12.2 v 13.7 kg; mean difference −1.3, 95% confidence interval −2.4 to −0.2; P=0.01). The rate of glucose intolerance was also lower in the intervention arm: 21% (67/320) compared with 28% (100/352) of controls had a fasting glucose of 5.1 mmol/L or greater or a 1 hour glucose challenge test result of greater than 7.8 mmol/L (P=0.02). Conclusion A low glycaemic index diet in pregnancy did not reduce the incidence of large for gestational age infants in a group at risk of fetal macrosomia. It did, however, have a significant positive effect on gestational weight gain and maternal glucose intolerance. Trial registration Current Controlled Trials ISRCTN54392969.

Definition of intertwin birth weight discordance.

OBJECTIVE: To establish the level of birth weight discordance at which perinatal morbidity increases in monochorionic and dichorionic twin pregnancy. METHODS: This prospective multicenter cohort study included 1,028 unselected twin pairs recruited over a 2-year period. Participants underwent two weekly ultrasonographic surveillance from 24 weeks of gestation with surveillance of monochorionic twins two-weekly from 16 weeks. Analysis using Cox proportional hazards compared a composite measure of perinatal morbidity (including any of the following: mortality, respiratory distress syndrome, hypoxic–ischemic encephalopathy, periventricular leukomalacia, necrotizing enterocolitis, or sepsis) at different degrees of birth weight discordance with adjustment for chorionicity, gestational age, twin–twin transfusion syndrome, birth order, gender, and growth restriction. RESULTS: Perinatal outcome data were recorded for 977 patients (100%) who continued the study with both fetuses alive beyond 24 weeks, including 14 cases of twin–twin transfusion syndrome. Adjusting for gestation at delivery, twin order, gender, and growth restriction, perinatal mortality, individual morbidity, and composite perinatal morbidity were all seen to increase with birth weight discordance exceeding 18% for dichorionic pairs (hazard ratio 2.2, 95% confidence interval [CI] 1.6–2.9, P<.001) and 18% for monochorionic twins without twin–twin transfusion syndrome (hazard ratio 2.6, 95% CI 1.6–4.3, P<.001). A minimum twofold increase in risk of perinatal morbidity persisted even when both twin birth weights were appropriate for gestational age. CONCLUSION: The threshold for birth weight discordance established by this prospective study is 18% both for dichorionic twin pairs and for monochorionic twins without twin–twin transfusion syndrome. This threshold is considerably lower than that defined by many retrospective series as pathologic. We suggest that an anticipated difference of 18% in birth weight should prompt more intensive fetal monitoring. LEVEL OF EVIDENCE: II

Randomized, clinical trial of bowel confinement vs. laxative use after primary repair of a third-degree obstetric anal sphincter tear.

PURPOSE: Third-degree tears are generally managed by primary anal sphincter repair. Postoperatively, some physicians recommend laxative use, whereas others favor bowel confinement after anorectal reconstructive surgery. This randomized trial was designed to compare a laxative regimen with a constipating regimen in early postoperative management after primary obstetric anal sphincter repair. METHODS: A total of 105 females were randomized after primary repair of a third-degree tear to receive lactulose (laxative group) or codeine phosphate (constipated group) for three days postoperatively. Patients were reviewed at three days and at three months postpartum. Recorded outcome measures were symptomatic and functional outcome and early postoperative morbidity. RESULTS: Forty-nine patients were randomly assigned to the constipated group and 56 patients to the laxative group. The first postoperative bowel motion occurred at a median of four (mean, 4.5 (range, 1–9)) days in the constipated group and at two (mean, 2.5 (range, 1–7)) days in the laxative group (P < 0.001). Patients in the constipated group had a significantly more painful first evacuation compared with the laxative group (P < 0.001). The mean duration of hospital stay was 3.7 (range, 2–6) days in the constipated group and 3.05 days in the laxative group (range, 2–5; P = 0.001). Nine patients in the constipated group complained of troublesome postoperative constipation compared with three in the laxative group (P = 0.033). Continence scores, anal manometry, and endoanal ultrasound findings were similar in the two groups at three months postpartum. CONCLUSIONS: Patients in the laxative group had a significantly earlier and less painful bowel motion and earlier postnatal discharge. There was no difference in the symptomatic or functional outcome of repair between the two regimens.

Outcome of second delivery after prior macrosomic infant in women with normal glucose tolerance

OBJECTIVE: Our aim was to estimate the obstetric outcome of second delivery in women with normal glucose tolerance whose first fetus was macrosomic (fetal weight ≥ 4,500 g). METHODS: Primiparas delivering a macrosomic infant during the years 1997–2000 were identified from a hospital computer database, and the obstetric outcome of a second delivery was analyzed up until June 2003. A control group (birth weight 3,000–3,500 g) served for comparison. RESULTS: Among 13,020 first pregnancies, 301 (2.3%) were macrosomic. A similar proportion in the macrosomic group, 156 of 301 (52%), and control group, 171 of 300 (57%), returned for second delivery (P = .252). Compared with controls, first macrosomic deliveries were characterized by higher rates of operative delivery, anal sphincter injury, and shoulder dystocia. At second delivery, 32% of neonates in the macrosomic group and 0.3% in the control group weighed 4,500 g or more (P < .001). More prelabor cesareans were performed in the macrosomic group compared with controls (27 of 156, 17.3%, compared with 8 of 171, 4.7%; P < .001). Among 104 women in the macrosomic group who labored after first vaginal delivery, 99% (103 of 104) delivered vaginally again compared with 44% (11 of 25) who labored after primiparous cesarean delivery (P < .001), which compares with 97% (146 of 150) and 77% (10 of 13), respectively, in the control group. CONCLUSION: Despite a one-third recurrence of macrosomia, first vaginal delivery of a macrosomic infant was associated with a high incidence of second vaginal delivery. Conversely, primiparous macrosomic cesarean delivery conveyed a high risk (56%) for repeat intrapartum cesarean whether macrosomia recurred or not. LEVEL OF EVIDENCE: II-2

A randomised control trial of low glycaemic index carbohydrate diet versus no dietary intervention in the prevention of recurrence of macrosomia

BackgroundMaternal weight and maternal weight gain during pregnancy exert a significant influence on infant birth weight and the incidence of macrosomia. Fetal macrosomia is associated with an increase in both adverse obstetric and neonatal outcome, and also confers a future risk of childhood obesity. Studies have shown that a low glycaemic diet is associated with lower birth weights, however these studies have been small and not randomised [1, 2]. Fetal macrosomia recurs in a second pregnancy in one third of women, and maternal weight influences this recurrence risk [3].Methods/DesignWe propose a randomised control trial of low glycaemic index carbohydrate diet vs. no dietary intervention in the prevention of recurrence of fetal macrosomia.Secundigravid women whose first baby was macrosomic, defined as a birth weight greater than 4000 g will be recruited at their first antenatal visit.Patients will be randomised into two arms, a control arm which will receive no dietary intervention and a diet arm which will be commenced on a low glycaemic index diet.The primary outcome measure will be the mean birth weight centiles and ponderal indices in each group.DiscussionAltering the source of maternal dietary carbohydrate may prove to be valuable in the management of pregnancies where there has been a history of fetal macrosomia. Fetal macrosomia recurs in a second pregnancy in one third of women. This randomised control trial will investigate whether or not a low glycaemic index diet can affect this recurrence risk.Current Controlled Trials Registration NumberISRCTN54392969

Ethnic variation between white European women in labour outcomes in a setting in which the management of labour is standardised—a healthy migrant effect?

Please cite this paper as: Walsh J, Mahony R, Armstrong F, Ryan G, O’Herlihy C, Foley M. Ethnic variation between white European women in labour outcomes in a setting in which the management of labour is standardised—a healthy migrant effect? BJOG 2011;118:713–718.

Leptin, fetal growth and insulin resistance in non-diabetic pregnancies.

BACKGROUND Interrogation of the association between leptin, insulin resistance and fetal growth may provide a biological link for the fetal programming of later metabolic health. AIMS Our aim was to clarify the relationship between maternal and fetal leptin, insulin resistance and fetal growth. STUDY DESIGN Maternal leptin, glucose and insulin were measured in early pregnancy and at 28weeks and the HOMA index calculated. At 34weeks, ultrasound scan assessed fetal weight and adiposity (abdominal wall width). At delivery birthweight was recorded and cord blood analyzed for fetal c-peptide and leptin. Analysis was performed using a multivariate linear regression model. SUBJECTS 574 non-diabetic pregnant women. OUTCOME MEASURES Fetal growth and maternal and fetal insulin resistance. RESULTS On multivariate analysis a relationship was identified between maternal and fetal leptin concentrations at each time point and maternal body mass index. Maternal leptin was related to insulin resistance in early pregnancy (β=0.15, p=0.02) and at 28week gestation (β=0.27, p<0.001). Fetal insulin resistance correlated with maternal leptin in early pregnancy (β=0.17, p=0.004); at 28weeks (β=0.12, p=0.05), and with leptin in cord blood (r=0.28, p<0.001). Fetal weight at 34weeks was related to maternal leptin in early pregnancy (β=0.16, p=0.02). Both maternal and fetal leptin correlated with infant size at birth (β=0.12, p=0.07 in early pregnancy, β=0.21, p=0.004 in cord blood), independent of all other outcome measures. CONCLUSION Our findings have confirmed that in a non-diabetic cohort there is a link between maternal and fetal leptin and insulin resistance. We also established a link between maternal leptin in early pregnancy and both fetal and neonatal size. These results add to the growing body of evidence suggesting a role for leptin in the fetal programming of childhood obesity and metabolic dysfunction.

Obstetric and metabolic implications of excessive gestational weight gain in pregnancy

To compare maternal characteristics, obstetric outcomes and insulin resistance in a cohort of women subdivided into those who did and those who did not exceed the Institute of Medicine (IOM) gestational weight gain guidelines.

Appropriate antenatal corticosteroid use in women at risk for preterm birth before 34 weeks of gestation

Please cite this paper as: Mahony R, McKeating A, Murphy T, McAuliffe F, O’Herlihy C, Foley M. Appropriate antenatal corticosteroid use in women at risk for preterm birth before 34 weeks of gestation. BJOG 2010;117:963–967.

Increasing rates of operative vaginal delivery across two decades: accompanying outcomes and instrument preferences

OBJECTIVE To examine rates and outcomes of operative vaginal delivery over a 20-year study period and the changing preference for various instruments during this period. STUDY DESIGN This retrospective analysis of prospectively gathered data was carried out at a large tertiary referral center from 1991 to 2010. All cases of operative vaginal delivery during the study period were recorded. The rates of instrumental delivery, as well as neonatal outcomes and instrument preference, were compared for individual 5-year epochs. RESULTS During the study period there were 156,130 deliveries of which 17,841 were operative vaginal deliveries, an incidence of 11.4/100 deliveries and 13.6/100 vaginal deliveries. There was an increase in the rate of operative vaginal delivery across the 20-year period (P < 0.0001; R(2) = 0.85; Slope = 0.42). When individual 5-year epochs were compared, the incidence of instrumental delivery increased from 7.3% (2340/31,937) in the first five years, 1991-1995, to 13.7% (6179/45,177) in the final five years, 2006-2010 (P < 0.0001; OR 2.34, 95% CI = 2.23-2.47). The perinatal mortality rate in cases of instrumental delivery was decreased when these time periods were compared (7.3/1000 (17/2340) vs. 1.8/1000 (11/6179); P = 0.003, OR 0.24, 95% CI = 0.11-0.52). The choice of instrument also varied, with 68.2% (1596/2340) of instrumental deliveries in 1991-1995 being carried out with forceps compared to 32.9% (2033/6179) in 2006-2010 (P < 0.001). CONCLUSION Rates of operative vaginal delivery have increased over the 20-year study period. The rate of perinatal mortality in infants who had an assisted vaginal delivery was decreased in the 5-year epoch at the end of the study compared with the period at the beginning. The rate of forceps delivery has fallen significantly, with vacuum delivery now being the choice of the majority of clinicians.