Cervical length after multifetal pregnancy reduction in remaining twin gestations

Multifetal pregnancy reduction is associated with an increased risk of prematurity. Because cervical length correlates with preterm delivery risk, we sought to determine whether multifetal pregnancy reduction twin gestations are associated with shorter cervical lengths compared with non-multifetal pregnancy reduction twins.

We compared an historic cohort of patients who underwent multifetal pregnancy reduction to twins (n = 35) to a control group of twin gestations without multifetal pregnancy reduction (n = 83) from July 1996 to January 2000. Both groups of patients were treated with identical protocols. Cervical lengths across gestation and pregnancy outcomes were compared.

Study and control groups did not differ significantly in mean maternal age (37.8 +/- 4.9 years vs 35.5 +/- 6.2 years; P =.06), median parity (0 [range, 0-1] vs 0 [range, 0-2]; P =.56), or mean gestational age at delivery (36.2 +/- 2.6 weeks vs 35.8 +/- 3.8 weeks; P =.50). The proportion delivering before 35 weeks of gestation was not significantly different (14.3% vs 30.1%; P =.10) nor was delivery before 32 weeks of gestation (8.6% vs 8.4%; P =.98). Cervical length did not differ significantly between the 2 groups. At 14 to 19 weeks the median was 3.9 cm (range, 2.4-6.0 cm) in the multifetal pregnancy reduction group versus 3.7 cm (range, 3.1-4.7 cm) in the control subjects (P =.15); at 20 to 25 weeks, the medians were 3.2 cm (range, 2.2-5.4 cm) and 3.7 cm (range, 1.5-5.7 cm), respectively (P =.43); and at 26 to 31 weeks the medians were 3.5 cm (range, 1.2-5.9 cm) versus 3.8 cm (range, 1.2-5.3 cm), respectively (P =.56).

Cervical length across gestation in twin pregnancies is not affected by multifetal pregnancy reduction, despite the likely inflammatory response expected to accompany this procedure.