Singleton fetal growth kinetics depend on the mode of conception

Objective: To study the impact of in vitro fertilization, with or without intracytoplasmic sperm injection (IVF/ICSI), frozen-embryo transfer (FET), and intrauterine insemination (IUI) on fetal growth kinetics throughout pregnancy and to compare the different modes of conception. Design: Retrospective cohort study. Setting: University. Patient(s): A total of 560 singleton pregnancies were included (96 IVF, 210 ICSI, 121 FET, and 133 IUI). Intervention(s): None. Main Outcome Measure(s): We compared crown-rump length (CRL) at the first trimester (T1: 11-13 weeks of gestation [WG] + 6 days), estimated fetal weight (EFW) at the second (T2: 21-23 WG + 6 days) and third (T3: 31-33 WG + 6 days) trimesters, and birth weight (BW) z-scores with those in the reference curves (Papageorghiou for T1, and Ego M2 for T2, T3, and birth). Multivariate analyses were performed. Result(s): For T1, the CRL was longer than the reference curve whatever the assisted reproductive technique (ART). For T2, EFW was significantly greater for all groups compared with the reference curve, and for T3 only FET singletons had a greater EFW. ICSI, IVF, and IUI singletons had a significantly lower BW compared with reference curves. For all ART fetuses, growth kinetics differed from T2. Only FET fetuses maintained their significantly above-reference growth values. The proportion of fetuses for which at least one period of growth loss was observed from T2 to birth was higher after IVF, ICSI, and IUI than after FET. Conclusion(s): For the first time, we have highlighted that fetal growth kinetics differed from T2 depending on the ART protocols used. They could have an impact on trophoblastic invasiveness and might lead to long-term health effects. (C) 2018 by American Society for Reproductive Medicine.