Live birth outcomes in infertile patients with class III and class IV obesity following fresh embryo transfer

ObjectiveAssess the effect of class III (body mass index BMI, kg/m²] 40–49.9) and class IV obesity (≥ 50) on clinical pregnancy and live birth outcomes after first oocyte retrieval and fresh embryo transfer cycle.DesignCohort studySettingAcademic centerPatientsPatients undergoing their first oocyte retrieval with planned fresh embryo transfer in our clinic between 01/01/2012 and 12/31/2018. Patients were stratified by BMI: 18.5–24.9 (n = 4913), 25–29.9 (n = 1566) 30–34.9 (n = 559), 35–39.9 (n = 218), and ≥ 40 (n = 114).InterventionNoneMain outcome measureLive birth rateResultsFollowing embryo transfer, there were no differences in pregnancy rates across all BMI groups (p value, linear trend = 0.86). However among pregnant patients, as BMI increased, a significant trend of a decreased live birth rate was observed (p value, test for linear trend = 0.004). Additionally, as BMI increased, a significant trend of an increased miscarriage rate was observed (p value, linear trend = < 0.001). Compared to the normal-weight cohort, women with a BMI ≥ 40 had a significantly higher rate of cancelled fresh transfers after retrieval (18.4% vs. 8.2%, OR 2.51; 95%CI 1.55–4.08). Among singleton deliveries, a significant trend of an increased c-section rate was identified as the BMI increased (p value, linear trend = <0.001).ConclusionOverall, patients with a BMI > 40 have worse IVF treatment outcomes compared to normal-weight patients. After embryo transfer, their pregnancy rate is comparable to normal-weight women; however, their miscarriage rate is higher, leading to a lower live birth rate for pregnant women in this population. Patients with a BMI > 40 have a c-section rate that is 50% higher than normal-weight patients.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10815-020-02011-1.