Is IVF/ICSI with Fresh Embryo Transfer Associated with Higher Mean Singleton Birth Weight Compared to Spontaneous Conception?

Introduction: To investigate for differences in birth weight between singletons born after in vitro fertilization (IVF) or intra-cytoplasmic sperm injection (ICSI) with fresh embryo transfer versus singletons born after spontaneous conception. Materials and methods: Retrospective analysis of singleton live birth weight after IVF or ICSI with fresh embryo transfer and live birth weight of singletons born after spontaneous conception during a twelve years period in a German university hospital. Patients were treated at the fertility unit of the university hospital. Inclusion criteria were defined as singleton delivery, delivery after spontaneous conception and fresh embryo transfer after IVF/ICSI treatment. Multivariate regression analysis was used to investigate the relationship between the dependent variable z-score (fetal birth weight) and the independent predictor variables maternal age and way of conception (spontaneous conception versus conception after IVF/ICSI with fresh embryo transfer). Results: In total, 6,786 singleton live births met the inclusion criteria and were analysed: 276 live births (151 males/125 females) after IVF/ICSI with fresh transfer and 6,510 live births after spontaneous conception (3,125 male/3,385 female). Mean z-score was -0.11 (± 0.92) for IVF/ICSI and fresh embryo transfer and 0.009 (± 0.9) for spontaneous conception. Z-scores depicted no inter-group differences (p=0.295). Multivariate regression analysis indicated way of conception (conception after IVF/ICSI and fresh transfer and spontaneous conception) but not maternal age as significant predictor of fetal birth weight. Conclusion: There is no association between IVF/ICSI with fresh embryo transfer and mean singleton birth weight compared to birth weight after spontaneous conception.