[Perinatal results in pregnancies obtained with embryo transfer in vitro fertilization: a case-control study].

Background: In 1978 the first successfull birth by in vitro fertilization took place and this assisted reproduction technique became alternative of treatment in the couples with infertility that had not obtained pregnancy with conventional treatments. The conditions of clinical treatment and laboratory improved, which were in greater number of pregnancies. In 1985 the first study was published that showed adverse perinatal results in pregnancies obtained with fertilization in vitro. Some researchers attributed these results to the increase in the number of multiple pregnancies, pregnant patients older than 35 years, and to the antecedents of infertility.

Objective: To compare the perinatal outcomes of pregnancies obtained by in vitro IVFET vs spontaneous pregnancies.

Patients And Methods: A retrospective, case-control study. All pregnancies obtained after IVF ET from October 1st 1999 to November 30th 2004 were compared with a control group of naturally conceived pregnancies and matched by maternal age and the number of fetus. Data concerning obstetric complications and perinatal outcomes were recorded and matched with their control.

Results: We analyzed 26 vs 52 singleton, 10 vs 20 twins, 5 vs 5 triplet pregnancies, there were no controls for the quadruplet and quintuplet pregnancies. The mean gestational age at delivery and Capurro score in the singleton pregnancies were 37.8 vs 38.8 y 38.2 vs 39.4 weeks for the study and control groups respectively (p < 0.05), the female sex was more frequent in singleton pregnancies obtained by FIVTE (p < 0.05). There were no statistically significant difference in the premature rupture of membranes, preterm labor, preeclampsia, gestational diabetes, placenta accreta, preterm delivery and low birth weight. The mean birth weight of the pregnancies obtained by IVF were of 2,962.8, 2,100 and 1,532 g for singleton, twin, and triplet respectively. A higher incidence of preterm delivery was found in twin pregnancies but it was not statistically significant.

Conclusions: The rates of adverse perinatal outcomes of the pregnancies after IVF were not higher than pregnancies conceived spontaneously. Twin pregnancies have a greater risk to cause preterm delivery not related to the IVFET procedure.