There is a dominant opinion that in vitro fertilization (IVF) leads to an increased incidence of twins, low birth weight (LBW) infants, prematurity and mortality. On the other hand, technical development of IVF and improvement of neonatal intensive care have increased the survival rate of neonates. The purpose of this study was to verify the tendency by comparing the clinical aspects of IVF and spontaneously conceived twins, and to establish methods to increase the survival rate of neonates after IVF.

Retrospective reviews were performed on all twin infants who were admitted to the nursery and NICU at Kangnam Sacred Heart Hospital, Hallym University from January 1, 2000 to December 31, 2006. Medical records of IVF twins (study group, n=92) and spontaneously conceived twins (control group, n=265) were analyzed and compared. Neonatal outcomes and complications, as well as obstetric outcomes, were analyzed and compared.

Mean gestational age and birth weight of the study group (34.6±3.5 weeks, 2,203.9±617.2 g) were considerably lower than those of the control group (36.3±2.4 weeks, 2,367.0±517.9 g). The frequency of prematurity less than 37 weeks (68.5% vs 51.3%) and extremely LBW (15.2% vs 6.4%) were also significantly higher in the study group. Other neonatal outcomes were all insignificant. The obstetric characteristics, maternal age (32.6±3.3 years vs 30.3±3.9 years) and the frequency of cesarean delivery(95.7% vs 79.9%) were significantly higher in the study group. Other obstetric outcomes were insignificant except for the frequency of incompetent internal os of cervix (36.2% vs 3.6%) and cerclage operation (38.3% vs 4.3%).

Based on the above results, clinical outcomes of twin infants will be further improved by careful attention and thorough antenatal care of the IVF twins.