Supplementary Material for: Fetal growth velocity according to the mode of assisted conception

Introduction: Pregnancies conceived through assisted reproductive techniques (ART) are on the rise worldwide and have been associated with a higher risk of placental related disease in the third trimester. Objective: To compare fetal growth velocity between pregnancies through ART and those spontaneously conceived, considering the origin of the selected oocyte (i.e. autologous or donated). Methods: A cohort was created of singleton pregnancies after assisted reproduction, admitted at our institution for delivery, between January 2020 and August 2022. Fetal growth velocity from the second trimester to delivery was compared against a gestational-age-matched group of pregnancies spontaneously conceived according to the origin of the selected oocyte. Results: 125 singleton pregnancies conceived through ART were compared to 315 singleton spontaneous conceptions. Overall, after adjusting for possible confounders, multivariate analysis demonstrated that ART pregnancies had a significantly lower EFW z-velocity from the second trimester to delivery (adjusted mean difference=-0.002; p=0.035) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR=2.32 [95%CI 1.15-4.68]). Also, when ART pregnancies were compared according to the type of oocyte, those conceived with donated oocytes showed a significantly lower EFW z-velocity from the second trimester to delivery (adjusted mean difference=-0.008; p=0.001) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR=5.33 [95%CI 1.34-21.5]). Conclusions: Pregnancies achieved through ART exhibit a pattern of lower growth velocity across the third trimester, especially those conceived with donated oocytes. The former represents a sub-group at the highest risk of placental dysfunction that may warrant closer follow-up.