Effect of Mode of Delivery in Nulliparous Women on Neonatal Intracranial Injury

Abstract

Vacuum extraction is steadily replacing forceps delivery in the United States, but the risk of serious neonatal injury from this procedure remains uncertain. This study used data from California to determine, in a series of 583,340 live-born singleton infants delivered by nulliparous women during 1992–1994, whether those delivered by vacuum extraction or other operative methods were more likely to incur major injuries. The range of birth weights was 2500 to 4000 gm. One-third of all infants were delivered using vacuum extraction or forceps (or both methods) or by cesarean. Neither vacuum extraction nor forceps delivery, separately or combined, significantly increased the risk of death before discharge from the hospital compared with spontaneous birth. The risk for infants delivered by cesarean, however, was significantly increased; the odds ratio was 3.7, regardless of whether a period of labor preceded surgery. Infants delivered by vacuum extraction did have significantly higher rates of subdural or cerebral bleeding, brachial plexus injury, seizures, central nervous system depression, and mechanical ventilation. Intraventricular hemorrhage was not a substantial risk. The absolute morbidity rate remained low for these infants. Forceps delivery was associated with significant increases in subdural or cerebral hemorrhage, facial nerve and brachial plexus injuries, and mechanical ventilation. The rate of intracranial hemorrhage was 7.4 times greater when both vacuum extraction and forceps were used than in spontaneous deliveries and 3.4 times higher than when vacuum extraction was used alone. Cesarean delivery correlated with significant increases in subdural or cerebral bleeding, intraventricular hemorrhage, seizures, central nervous system depression, mechanical ventilation, and feeding difficulty. The risk of intracranial bleeding was not greater after section delivery with no attempt at labor than in spontaneously born infants. All forms of operative intervention undertaken during labor increase the risk of intracranial bleeding. Because the risk is not increased when cesarean section is undertaken before labor implies that abnormal labor is the key risk factor. N Engl J Med 1999;341:1709–1714