Phenotypic differences in children conceived from fresh and thawed embryos in in vitro fertilization compared with naturally conceived children.

OBJECTIVE: To determine whether anthropometric and biochemical features differ in in vitro fertilization (IVF) children conceived via fresh (IVFF) or thawed (IVFT) embryo transfer compared with naturally conceived controls.

DESIGN: A cross-sectional controlled study.

SETTING: University clinical research unit.

PATIENT(S): Healthy prepubertal children (3.5-11.0 years), singletons, born at term (>37 weeks), who were either naturally conceived (controls; n = 94) or IVF children conceived via the transfer of a fresh (IVFF; n = 72) or thawed (IVFT; n = 43) embryo.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): Assessments of anthropometry (adjusted for parental variables), dual-energy X-ray absorptiometry-derived body composition, fasting plasma growth factors, lipids, and parameters of glucose regulation.

RESULT(S): The IVFF but not the IVFT children weighed less at birth than the control children. The IVFF children were taller than both the controls and IVFT children. Sex-specific analyses showed height differences among girls, with IVFF girls being taller than their control and IVFT counterparts. Taller stature in IVFF children was associated with increased insulin-like growth factor I (IGF-I) concentrations compared with controls, whereas the IVFT children displayed increased IGF-II and decreased insulin-like growth factor binding protein 3 (IGFBP-3) concentrations compared with the controls. More favorable lipid profiles were also evident in IVFF but not IVFT children compared with the control children.

CONCLUSION(S): These preliminary findings highlight that the transfer of a fresh versus a thawed IVF embryo affects height, plasma growth factor, and lipid profiles in childhood. Therefore, embryo derivation should be considered when assessing physical and biochemical phenotype of IVF children.