High-quality embryos retain their implantation capability in overweight women

To assess the effect of obesity on implantation rate, pregnancy rate and course of pregnancy in young women undergoing IVF in whom only high-quality embryos were transferred, a cohort study included women attending the IVF unit in 2006-2007 with favourable parameters to achieve pregnancy (<38years, fewer than three IVF cycles, transfer of two high-quality embryos), grouped by body mass index (BMI). Of 230 women, 160 had a BMI ⩽25kg/m(2) (mean 21.6±2.2) and 73 had BMI >25kg/m(2) (mean 29.5±3.7). The overweight group had a higher consumption of gonadotrophins during stimulation. There were no between-group differences in treatment protocols, duration of gonadotrophin stimulation, maximal oestradiol concentrations, endometrial thickness and number of oocytes retrieved/fertilized, or in rates of pregnancy (51.3%, 52.1%), implantation (34.5%, 37.5%), multiple pregnancy, and abortion. Rate of gestational diabetes or pregnancy-induced hypertension was higher in the overweight group (23.3%, 8.2%; P=0.045). Within the overweight group, those with multiple pregnancies were at highest risk (31.3%, 6.9%; P=0.031). In conclusion, implantation and pregnancy rates are not compromised in overweight women when high-quality embryos are transferred. However, in overweight women, pregnancy complications remain high, mainly in those with multiple pregnancies.