A RANDOMIZED PROSPECTIVE TRIAL OF THE OBSTETRIC FORCEPS VERSUS THE M-CUP VACUUM EXTRACTOR

OBJECTIVE: Our purpose was to determine the efficacy of the obstetric forceps versus the M-cup, a new vacuum extractor cup, and maternal-neo natal complication rates. STUDY DESIGN: Over a 10-month period operati ve vaginal deliveries were randomized between the obstetric forceps an d the M-cup vacuum extractor cup. Maternal demographics, indication fo r intervention, analgesia, position, station, degree of asynclitism, f etal caput-molding, and time from application to delivery were prospec tively recorded. Episiotomy and extensions, lacerations, and the reaso n for abandonment of the randomized instrument were noted in both grou ps. Fetal weight, Apgar scores, cord arterial gases, hyperbilirubinemi a, phototherapy, and any evidence of fetal trauma were documented at d elivery or in the nursery. RESULTS: Six hundred thirty-seven women wer e randomized, 315 in the forceps group and 322 in the M-cup group. The re were no differences in maternal demographic variables. The station, position, degree of asynclitism, or requirement for rotation was not different between the groups. The corrected efficacy rates were forcep s 92% and M-cup 94% (p = 0.217). The M-cup deliveries were accomplishe d more rapidly than forceps deliveries (p < 0.001) and were associated with a lower rate of episiotomy (p < 0.001), third-degree (p < 0.001) and fourth-degree (p = 0.002) lacerations, but blood loss as clinical ly estimated (p = 0.232) or as measured by hemoglobin levels (p = 0.16 6) was not significantly different. Forceps deliveries were associated with fewer clinically diagnosed cephalhematomas (p = 0.015) than M-cu p deliveries were, but there were no differences in the number of neon ates diagnosed with hyperbilirubinemia (p = 0.377) or in the number of infants treated with phototherapy (p = 0.660). CONCLUSIONS: The M-cup vacuum extractor cup appears to be as efficient (and faster) than the obstetric forceps but is associated with significantly more fetal cep halhematomas, whereas maternal injuries are more common with the force ps.