Macrosomia: maternal and fetal outcome

Maternal and neonatal complications of fetal macrosomia: cohort study

OBJECTIVE

To estimate the risks of maternal and neonatal complications in pregnancies with macrosomia.

METHODS

This was a retrospective cohort study conducted at a large maternity unit in the UK between January 2009 and December 2016. The incidence of maternal and neonatal complications in pregnancies with macrosomia, defined as birth weight (BW) > 4000 g, and in those with severe macrosomia, defined as BW > 4500 g, was compared with that in pregnancies with normal BW (2500-4000 g). Regression analysis was performed to determine odds ratios (ORs) for complications in macrosomic pregnancies compared to those with normal BW.

RESULTS

The study population of 35 548 pregnancies included 4522 (12.7%) with macrosomia, of which 643 (1.8%) had severe macrosomia, and 31 026 (87.3%) with normal BW. In the macrosomia group, the adjusted OR was 3.1 (95% CI, 2.6-3.6) for Cesarean section for failure to progress, 2.4 (95% CI, 2.0-3.0) for severe postpartum hemorrhage, 2.3 (95% CI, 1.9-2.8) for obstetric anal sphincter injury, 10.4 (95% CI, 8.6-12.6) for shoulder dystocia, 28.5 (95% CI, 8.9-90.7) for obstetric brachial plexus injury, 32.3 (95% CI, 3.8-278.2) for birth fractures and 4.4 (95% CI, 2.2-8.8) for hypoxic-ischemic encephalopathy. The respective values in pregnancies with severe macrosomia were 4.3 (95% CI, 3.1-6.1), 2.9 (95% CI, 1.9-4.4), 3.1 (95% CI, 1.9-5.1), 28.7 (95% CI, 20.8-39.8), 73.9 (95% CI, 15.1-363.2), 87.2 (95% CI, 7.7-985.0) and 13.8 (95% CI, 5.2-36.8).

CONCLUSION

Macrosomia is associated with serious adverse perinatal outcomes. This study provides accurate estimates of risks to aid in pregnancy management. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Maternal and neonatal complications of fetal macrosomia: systematic review and meta-analysis

OBJECTIVE

To determine accurate estimates of risks of maternal and neonatal complications in pregnancies with fetal macrosomia by performing a systematic review of the literature and meta-analysis.

METHODS

A search of MEDLINE, EMBASE, CINAHL and The Cochrane Library was performed to identify relevant studies reporting on maternal and/or neonatal complications in pregnancies with macrosomia having a birth weight (BW) > 4000 g and/or those with birth weight > 4500 g. Prospective and retrospective cohort and population-based studies that provided data regarding both cases and controls were included. Maternal outcomes assessed were emergency Cesarean section (CS), postpartum hemorrhage (PPH) and obstetric anal sphincter injury (OASIS). Neonatal outcomes assessed were shoulder dystocia, obstetric brachial plexus injury (OBPI) and birth fractures. Meta-analysis using a random-effects model was used to estimate weighted pooled estimates of summary statistics (odds ratio (OR) and 95% CI) for each complication, according to birth weight. Heterogeneity between studies was estimated using Cochran's Q, I2 statistic and funnel plots.

RESULTS

Seventeen studies reporting data on maternal and/or neonatal complications in pregnancy with macrosomia were included. In pregnancies with macrosomia having a BW > 4000 g, there was an increased risk of the maternal complications: emergency CS, PPH and OASIS, which had OR (95% CI) of 1.98 (1.80-2.18), 2.05 (1.90-2.22) and 1.91 (1.56-2.33), respectively. The corresponding values for pregnancies with BW > 4500 g were: 2.55 (2.33-2.78), 3.15 (2.14-4.63) and 2.56 (1.97-3.32). Similarly, in pregnancies with a BW > 4000 g, there was an increased risk of the neonatal complications: shoulder dystocia, OBPI and birth fractures, which had OR (95% CI) of 9.54 (6.76-13.46), 11.03 (7.06-17.23) and 6.43 (3.67-11.28), respectively. The corresponding values for pregnancies with a BW > 4500 g were: 15.64 (11.31-21.64), 19.87 (12.19-32.40) and 8.16 (2.75-24.23).

CONCLUSION

Macrosomia is associated with serious maternal and neonatal adverse outcomes. This study provides accurate estimates of these risks, which can be used for decisions on pregnancy management. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Development of risk scoring scheme for prediction of cesarean delivery due to cephalopelvic disproportion in Lamphun Hospital, Thailand

AIM

To develop a simple risk scoring scheme for the prediction of cesarean delivery due to cephalopelvic disproportion (CPD) in Lamphun Hospital, Thailand.

METHODS

A case-control study was conducted including 116 pregnant women with cesarean delivery due to CPD and 307 pregnant women delivering by normal labor. Obstetric information was retrieved from medical records. Risk indicators measurable at the time of admission were analyzed by a stepwise logistic regression to obtain a set of statistically significant predictors. Regression coefficients were transformed into item scores and added up to a total score. Risk of cesarean delivery due to CPD was analyzed using total scores as the only predictor.

RESULTS

A risk scoring scheme was developed from five obstetric predictors: maternal age, height, parity, pregnancy weight gain and symphysis-fundal height. Item scores ranged from 0 up to 3.5 and the total score from 0-14.5. The scheme explained, by the area under the receiver operating characteristic curve, 88% of cesarean delivery due to CPD. The likelihood of cesarean delivery due to CPD in pregnant women with low risk (scores below 5), moderate risk (scores 5-9.5) and high risk (scores 10 and over) were 0.09, 0.86 and 10.11, respectively.

CONCLUSIONS

The risk of cesarean delivery due to CPD may be forecasted by a simple scoring scheme using five predictors that correctly identified women with low, moderate and high risk. This scheme may be applicable to physicians and midwives for identifying high-risk pregnant women in order to take appropriate action.

Suspicion and treatment of the macrosomic fetus: a review

OBJECTIVE

To review the prevalence of and our ability to identify macrosomic (birthweight >4000 g) fetuses. Additionally, based on the current evidence, propose an algorithm for treatment of suspected macrosomia.

STUDY DESIGN

A review.

RESULTS

According to the National Vital Statistics, in the United States, the prevalence of newborns weighing at least 4000 g has decreased by 10% in seven years (10.2% in 1996 and 9.2% in 2002) and 19% for newborns with weights >5000 g (0.16% and 0.13%, respectively). Bayesian calculations indicates that the posttest probability of detecting a macrosomic fetus in an uncomplicated pregnancy is variable, ranging from 15% to 79% with sonographic estimates of birth weight, and 40 to 52% with clinical estimates. Among diabetic patients the post-test probability of identifying a newborn weighing >4000 g clinically and sonographically is over 60%. Among uncomplicated pregnancies, there is sufficient evidence that suspected macrosomia is not an indication for induction or for primary cesarean delivery. For pregnancies complicated by diabetes, with a prior cesarean delivery or shoulder dystocia, delivery of a macrosomic fetus increases the rate of complications, but there is insufficient evidence about the threshold of estimated fetal weight that should prompt cesarean delivery.

CONCLUSION

Due to the inaccuracies, among uncomplicated pregnancies suspicion of macrosomia is not an indication for induction or for primary cesarean delivery.

Gestational Weight Gain, Macrosomia, and Risk of Cesarean Birth in Nondiabetic Nulliparas

OBJECTIVE

To examine how the association between excessive weight gain and cesarean birth is modified by infant birth weight in nondiabetic women.

METHODS

We designed a retrospective cohort study of singleton, term, nulliparous women with cephalic presentations delivering at a single university hospital. Subjects with diabetes were excluded. Bivariate and multivariate analyses were performed. Regression models controlled for maternal age, maternal prepregnancy body mass index, gestational age, ethnicity, smoking, birth weight, and date of delivery.

RESULTS

Women gaining above Institute of Medicine guidelines were more likely to have a cesarean birth, even if birth weight was less than 4,000 g. In the multivariate analysis, women with excessive weight gain had an odds ratio of 1.40 (95% confidence interval 1.22-1.59) for cesarean birth. When absolute weight gain (total pregnancy weight gain minus birth weight and placental weight) was used in the multivariate analysis, excessive weight gain was still an independent predictor of cesarean delivery. Although macrosomia was a stronger predictor of cesarean than weight gain alone, excessive weight gain was much more common than macrosomia in our cohort.

CONCLUSION

Excessive weight gain during pregnancy is an independent risk factor for cesarean birth, even when birth weight is not excessive. Other mechanisms besides macrosomia may be involved in the association between high weight gain and cesarean birth. We estimate that of the approximately 288,000 primary cesarean deliveries performed in nulliparas annually in the United States, 64,000 would be prevented if no women gained above Institute of Medicine recommendations.

LEVEL OF EVIDENCE

II-2