The Affects of the Initial Fetal Number on Pregnancy Outcomes before Multifetal Pregnancy Reduction

Hyun, Woo Young; Lee, Jong Pyo; Yoo, Keun Jai; Kim, Kye Hyun; Song, In Ok; Yeon, Hye Jung; Paik, Eun Chan; Koong, Mi Kyoung; Son, Il Pyo; Jun, Jong Young; Kang, Inn Soo

Abstract

Multifetal pregnancy reduction(MFPR) appears to be an efficacious method for impro-ving the perinatal outcome of high order multifetal pregnancies(three or more fetuses). But it is controversial that larger initial fetal number before MFPR affects pregnancy outcomes adversely. The purpose of this study is to determine the affects of the initial fetal numbers on pregnancy outcomes and to compare the obstetrical outcomes according to the initial fe-tal numbers. Eighty four patients who conceived triplet or more by assisted reproductive technology(ART) in our infertility clinics and underwent MFPR to twins between January 1993 and December 1995. Sixteen patients were lost follow-up. Among the remaining 68 patients, four pateints were excluded from this study because of the pregnancy loss before 20 weeks gestation. The patients(n=64) were divided into three groups by the initial fetal number before reduction. 33 patients with triplet gestations(group 1), 18 patients with qua-druplets gestations(group 2), and 13 patients with quintuplet or more gestations(group 3) were retrospectively enrolled. Gestational age at delivery and birthweights were compared according to the initial fetal numbers. The mean maternal age was similar in each three groups. The results were as follows : 1) Although there was a trend of decreasing gestati-onal weeks at delivery and decreased birthweight in each groups(mean+/-SEM : 36.9+/-0.3, 34.7+/-1.3, 32.7+/-1.9 and 2,600+/-58, 2,161+/-215, 1,855+/-249 respectively), there were no stati-stical difference between group 1 and group 2, but there were significantly lower in group 3, compared with group1(p < 0.05). 2) The incidence of birth before 36 weeks gestation in each group 1, group 2, and group 3 were 12.1%, 38.9%, and 53.8% respectively(p < 0.05). 3) The incidence of low birthweight( < 2,500gm) in each group 1, group 2, and group 3 were 30.3%, 55.6%, and 69.2% respectively(p < 0.05). In conclusion, although MFPR reduced the high order multifetal pregnancy into twin pregnancy, the duration of gestation and the birth weight of newborn were still had a tendency of shortening and low respectively in high order multifetal pregnancy. Therefore strict control of the number of dominant follicles during superovulation and the number of transfered embryo in in vitro fertilization(IVF) is required for improving the pregnancy outcomes in ART.