[Embryonal and early fetal growth after in vitro fertilization and embryo transfer].

Echographic examination allows correlations between crown-rump length and gestational age. In this study the embryonic and early fetal growth after in vitro fertilization and embryo transfer was evaluated by ultrasound (U.S.) marks. 97 measurements in 54 pregnancies between day 39 and 80 after successful fertilization has been performed. Early fetal growth retardation was detected by U.S. when compared to the Robinson curve for normal pregnancy and confirmed after correction for the instrument error. This delay of 3, 3.5 days disappears around the 13 week of pregnancy and is not related to the baby weight at birth. An implantation delay may explain this difference in growth rate between normal and after F.I.V. and E.T. pregnancies.