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Mode of Delivery at Term and Adverse Neonatal Outcomes

Walsh, Colin A.; Robson, Michael; McAuliffe, Fionnuala M.

Obstetrical & Gynecological Survey:
doi: 10.1097/01.ogx.0000430373.76627.f4
Obstetrics: Management of Labor, Delivery, and the Puerperium

ABSTRACT: Debate still rages on the high rate of cesarean deliveries (CDs). Operative vaginal delivery usually results in a healthy neonate, but concerns are voiced about the iatrogenic perinatal morbidity, and thus many clinicians avoid this delivery option. This cohort study was undertaken to determine rates of peripartum neonatal mortality, neonatal encephalopathy, and neonatal death secondary to intracranial hemorrhage (ICH) in term neonates.

The study included 76,810 term, singleton neonates 500 g or greater delivered between 2000 and 2009. Data were extracted from reports on all cases of perinatal death, fatal neonatal ICH, and neonatal encephalopathy. The primary outcome was the rate of peripartum death by mode of delivery. Secondary outcomes were rates of neonatal encephalopathy and mortality related to neonatal ICH by mode of delivery and the relationship between instrument choice and adverse outcomes. Statistical analysis was performed with Statsdirect 2.7.8.

In 76,810 neonates 500 g or greater delivered at more than 37 weeks’ gestation, CD rates were 17.3% for the overall population and 16.6% for 12,764 term singletons. Among CDs, 36% were elective, 60% were intrapartum before full dilatation, and 4% were intrapartum at full dilatation. Among women who delivered vaginally, 17% had an operative vaginal delivery (14% of overall population); of these, 69% and 31%, respectively, were vacuum- and forceps-assisted deliveries. Of the 64,555 women reaching full cervical dilatation, 82.3%, 16.9%, and 0.8%, respectively, had spontaneous vaginal delivery, operative vaginal delivery, and CD. Among the women who reached full dilatation, the overall rate of peripartum fetal or neonatal mortality was 0.31 per 1000 neonates (20/64,555). For neonates born by CD in the second stage, the peripartum mortality rate was 1.96 per 1000, and that for neonates born by spontaneous vaginal delivery was 0.17 per 1000 (P = 0.09). Rates for peripartum mortality in vacuum-assisted and forceps-assisted deliveries were 1.0 (P = 0.001) and 0.3 (P = 0.46) per 1000 neonates, respectively, as compared with spontaneous vaginal delivery. The overall rate of neonatal encephalopathy was 1.46 per 1000 in women reaching full dilatation. In neonates delivered by second-stage CD, the rate was 3.9 per 1000, similar to the overall rate for operative vaginal delivery (4.2/1000). Rates in neonates delivered by vacuum and forceps assistance were 4.7 and 3.2 per 1000, respectively. For all modes of operative delivery, the rate of neonatal encephalopathy was higher in neonates delivered by spontaneous vaginal delivery. Six peripartum deaths secondary to neonatal ICH occurred, for an overall incidence of 0.08 per 1000 neonates. The highest rate of ICH-related mortality was in neonates born by vacuum-assisted delivery (0.4/1000) compared with 0.3 and 0.02 per 1000 neonates born by forceps-assisted and spontaneous vaginal delivery, respectively. Among 7684 term neonates delivered by intrapartum CD in the first stage, one death secondary to ICH occurred. No neonatal deaths occurred secondary to ICH in neonates delivered by CD at full dilatation. The rate of ICH-related mortality was 3 to 4 per 10,000 for vacuum and forceps deliveries, with no significant difference between instruments.

One contributing factor to increased CD rates is the sharp reduction in the proportion of women undergoing operative vaginal delivery. This study found no difference in the rates of peripartum mortality or neonatal encephalopathy in neonates delivered by vacuum-assisted, forceps-assisted, or second-stage CD. Operative vaginal delivery by an experienced practitioner is appropriate in women who require expedited delivery.

Author Information

National Maternity Hospital and UCD Obstetrics and Gynaecology, School of Medicine and Medical Science, University College Dublin, National Maternity Hospital, Dublin, Ireland

© 2013 by Lippincott Williams & Wilkins.