双胎妊娠分娩时机选择的多中心回顾性分析

A multicentered and retrospective study on the timing for delivery in twin pregnancies

目的降低双胎妊娠围产儿不良预后的发生率,探讨合理的双胎终止妊娠时间。方法对1993年1月到2003年10月十年期间在上海地区六家医院妇产科分娩的655例双胎妊娠进行回顾性分析,分别计算出各孕周大小胎儿出生体重的百分位数、小于孕龄儿(smallforgestationalage,SGA)和重度窒息的发生率。结果1.整个孕期双胎妊娠中小胎儿出生体重的第50百分位数均明显落后于单胎胎儿,33周前大胎儿出生体重的第50百分位数与单胎胎儿接近,33周后差别逐渐增大,39周后大小胎儿出生体重与单胎相比差别更为显著。与单胎妊娠不同,双胎妊娠大胎儿在39周、小胎儿40周达最大出生体重(3073g和2670g),在此之后出生体重反而下降,41周时明显降低(2555g和2303g,P<0.05)。2.双胎妊娠大小胎儿SGA发生率随孕龄的增加呈上升趋势,39周后上升幅度明显增加,41周达到最高(P<0.05)。3.39周后小胎儿重度窒息的发生率明显增加。结论39周后双胎妊娠胎儿出生体重呈下降趋势,SGA及小胎儿围产期重度窒息的发生率明显上升,因此双胎妊娠的分娩时间不应超过39周。

Objective To investigate the timing for delivery in twin pregnancies to improve the perinatal outcome. Methods A multicentered and retrospective study was conducted on 655 women with twin pregnancies in 6 hospitals of Shanghai from Jan 1993 to Oct 2003. The average birthweight （BW） for both twins in different gestation, the incidence of small for gestational age （SGA） and severe neonatal asphyxia were analyzed. Results For the smaller babies in all twins, the 50 percentile of the birth weight was far behind the singletons throughout the pregnancy. But for the larger babies, it was similar to the singletons if delivered before 33 weeks, lighter than the singletons if after 33 weeks and remarkable difference was shown beyond 39 weeks. The largest BW of the larger babies was 3073 g presented at 39 weeks, while 2670 g for the smaller babies at 40 weeks after which the average BW was decreased. It reached 2555 g and 2303 g at 41 weeks for the larger and smaller babies, respectively （P〈0.05）. The incidence of SGA climbed up with the increasing of gestational age in the third trimester, rose quickly after 39 weeks and reached the peak value at 41 weeks（P〈0.05）. Signi-ficant increase in the incidence of severe neonatal asphyxia was found in the smaller babies after 39 weeks. Conclusions The twin pregnancies should be terminated before 39 weeks of gestation.