Perinatal outcome after in vitro fertilisation.

A prospective series of 90 consecutive pregnancies (70 singleton, 16 twin and 4 triplet pregnancies) resulting in births of 114 infants after in vitro fertilisation (IVF) at Rigshospitalet were compared to a control group of pregnancies and deliveries in 70 non-IVF infertility patients with singleton pregnancies and 20 women with normal fertility with twin (n = 16) or triplet (n = 4) pregnancies. No differences in the incidence of third trimester pregnancy complications, abnormal fetal karyotypes or malformations were found. The number of women with spontaneous onset of labor and the gestational age at delivery were similar in the IVF and control groups. In singleton deliveries, the birth weight was lower (p < 0.025) in the IVF group (median 3145 g, range 890-4300 g) than in the control group (3399 g, 2592-4850 g), whereas in multiple gestation similar birth weights were found in the IVF and control groups. We conclude that the birth weight in singleton deliveries after IVF is lower than the birth weight in infertility patients treated differently. The cause of this difference remains obscure.