P-770 Is there an association between blood hCG elevation rate in very early IVF pregnancy and adverse pregnancy outcomes?

Abstract

Abstract Study question Is a slow elevation rate between the first and second hCG values following a successful fresh IVF cycle associated with long-term pregnancy outcomes? Summary answer A slow rate of hCG elevation in early IVF pregnancies is associated with an increased risk for low birth weight neonates. What is known already IVF pregnancies are associated with higher prevalence of late obstetrical complications such as preterm birth, preeclampsia and small for gestational age. Different baseline characteristics and treatment parameters are associated with obstetrical complications. Abnormal, mostly slow, hCG elevation patterns have been strongly associated with short-term adverse pregnancy outcomes such as non-viability, miscarriage, early fetal demise and ectopic pregnancies. However, the long-term impact of slow hCG elevation rate on pregnancies that do continue to term is unknown. Study design, size, duration Single center cohort study between 2008-2019 including 703 fresh cycles resulting in live singleton birth. Full obstetrical data for these pregnancies was available. Participants/materials, setting, methods The first blood hCG measurement was performed 14±1.4 days after ovum pick-up (OPU), and the second one 48-72h later. The slope between the two measurements was calculated and adjusted per day. Slow hCG elevation was defined as a slope value below the 10th percentile. Maternal and short-term neonatal outcomes were compared between cycles with a slow elevation (n = 71) and a “normal” elevation (n = 632) in hCG values. Multivariate analysis was used to control for potential confounders. Main results and the role of chance There were no differences between the slow and normal hCG elevation groups in maternal age, numbers of retrieved oocytes, ICSI rates, number of transferred and usable embryos, and gestational age at delivery. Neonates from cycles with a slow hCG elevation weighed significantly less (2876±619 gr vs. 3083±553 gr, p < 0.005) and were at a higher risk (21% vs. 12%, OR = 1.96, 95% CI 1.06-3.64) of having low birth weight (LBW) (below 2500 grams). Women with slow hCG elevation rate had more hypertension-preeclampsia related complications (11% vs. 6%, p < 0.05), although barely reaching statistical significance in the multivariate analysis (OR = 1.76, 95% CI 1.0-3.6). Limitations, reasons for caution Retrospective design, single center, applicability to fresh cycles only. Wider implications of the findings Very early (5th week) initial blood hCG elevation slope, measured only in IVF gestations, might be a novel marker for identifying patients at risk for hypertensive complications during pregnancy and low birth-weight neonates. Tighter prenatal care for these patients could potentially reduce pregnancy complications and improve long-term outcome. Trial registration number not applicable