Factors Affecting Complete Fetal Loss Following Multifetal Pregnancy Reduction

Kim, Hye Ok; Kim, Mun Young; Song, Hyun Jeong; Park, Chan Woo; Hur, Girl; Kim, Jin Yeong; Yang, Kwang Mun; You, Keun Jae; Song, In Ok; Jun, Jong Young; Koong, Mi Kyoung; Kang, inn Soo

Abstract

OBJECTIVE
To identify the factors affecting the complete fetal loss following multifetal pregnancy reduction (MFPR). DESiGN: Retrospective clinical study.
METHODS
A total of 256 consecutive treatments of MFPR in iVF-ET cycles performed between 1992 through 2000 in Samsung Cheil hospital were analyzed. MFPR was done around 8 weeks of gestation by transvaginal ultrasono-guided aspiration in multiple pregnancies and reduced to singleton or twins. Stepwise logistic regression was performed to identify the factors affecting the final outcome of pregnancy after MFPR. Dependent variable was complete fetal loss and the independent variables were maternal age, paternal age, initial number of gestational sac (iGSNO), initial number of fetal heart beat, the number of remaining live fetus after MFPR, and chorionicity.
RESULTS
The total survival rate was 87.9%, and total fetal loss rate after MFPR was 12.1%. Total fetal loss occurred within four weeks from MFPR procedure was 1.95%. Total loss occurred after four weeks of procedure and before 24 gestational weeks was 8.2%. Seventy nine percent (202/256) of pregnancies delivered after 34 weeks of gestation. The survival rate of pregnancies reduced to singleton was significantly higher than that of pregnancies reduced to twins (93.5% vs. 86.7%, p<0.05). The mean (+/-SEM) gestational age at delivery was 36.2+/-1.0 and 34.1+/-0.5 weeks for pregnancies reduced to singletons and twins, respectively (p=0.065). Logistic regression analysis revealed that the maternal age, the number of initial gestational sac (iGSNO), and the number of remaining live fetus after MFPR significantly affected the rate of total fetal loss (Z = 0.174'age + 0.596'iGSNO + 1.324'remaining fetuses-12.07), (p<0.05).
CONCLUSiONS
MFPR seems to be a relatively safe and efficient method to improve the obstetric outcome in high order multiple pregnancy. Because the maternal age, the number of initial gestational sac and the remaining live fetuses after MFPR affect the total fetal loss rate, restriction of the number of transferred embryos according to the age and MFPR to singleton fetus could be considered for the better obstetric outcome in iVF pregnancy.