The Influence of Monochorionicity on the Perinatal Outcomes in Spontaneously Conceived Twins

Shin, Joong Sik; Yang, Jae Hyug; Ryu, Hyun Mee; Kim, Moon Young; Han, Jung Yeol; Ahn, Hyun Kyong; Chung, Jin Hoon; Lim, Ha Jung; Choi, June Seek; Kim, Joo Oh; Kim, Min Hyoung; Park, Su Hyun; Cho, Hye Jin; Choi, Kyu Hong

Abstract

OBJECTIVE
The Purpose of this study was to evaluate monochorionicity as a risk factor for adverse perinatal outcomes in spontaneously conceived twins.
METHODS
Using an established database, the study included pregnant women with spontaneously conceived twin gestations between January 1998 and December 2002. From a total of 1145 twin deliveries, 371 spontaneous twin pregnancies were observed in Department of Obstetrics and Gynecology in Samsung Cheil Hospital and Women's Healthcare Center. Chorionicity was established by histologic examination and divided into two groups, monochorionic (diamnionic and monoamnionic) twins (MC) and dichorionic diamnionic twins (DC). The obstetric and neonatal outcomes were compared between the two groups.
RESULTS
There were 176 MC and 195 DC twin deliveries following natural fertilization. The incidence of intrauterine growth restriction was significantly higher (16.4% vs. 5.4%, P<.001) in MC twins. However, there were no statistically significant differences in the frequency of antepartum or intrapartum complications such as preterm delivery, preeclampsia, placenta previa and gestational diabetes mellitus between the two groups. In addition, there were no statistically significant difference in the frequency of neonatal complications, congenital anomalies, Apgar scores, perinatal mortality, morbidity and duration of neonatal intensive care unit admission.
CONCLUSION
When compared with DC twin group, MC twin group is more likely to have a higher incidence of intrauterine growth restriction in natural fertilization. However, monochorionicity is not a risk factor for adverse obstetric outcomes, perinatal mortality and morbidity in spontaneously conceived twins in our study.