[Impact of BMI on fresh cycle embryo transfer outcome of IVF/ICSI in patients with early follicular phase prolonged protocol].

To investigate the impact of body mass index (BMI) on clinical effect and fresh cycle embryo transfer pregnancy outcome of in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) in patients with early follicular phase prolonged protocol. From January 1st, 2018 to July 1st, 2020, 2 257 cases of early follicular long-term protocol in IVF/ICSI and embryo transfer were collected using the clinical assisted reproductive technologies management system software database of the First Affiliated Hospital of Nanjing Medical University. Patients were divided into three groups according to the recommended Asian BMI cut-off points: low body mass group (BMI<18.5 kg/m), normal body mass group (18.5≤BMI<24.0 kg/m), and high body mass group (BMI≥24.0 kg/m). The ovarian stimulation characteristics among the groups were investigated. Then 1 741 fresh embryo transfer cycles were selected and divided into three groups as above, and then the ovulation induction and clinical outcomes were analyzed among the groups. There were significant differences in the starting dosage of gonadotrophin (Gn), total dosage of Gn and days of Gn used among the low body mass group, normal body mass group, and high body mass group in the 2 257 IVF/ICSI cycles (all <0.01). The high body mass group needed the most amount of Gn [(2 159±668) U] and longest Gn days [(12.3±2.5) days]. The estradiol and progesterone levels [(7 474±4 852) pmol/L, (3.4±1.9) nmol/L] on hCG trigger day in the high body mass group were lower than those in the low body mass group and normal body mass group (all <0.01). The oocytes retrieved in high body mass group (8.4±4.1) were significantly lower than normal body mass group (<0.05). The normal fertilization number, the available embryo number and high quality embryo number were all lower in the high body mass group than other two groups, while no significant difference showed (all >0.05). In 1 741 cycles of fresh embryo transfer, the average number of transplanted embryos in the low body mass group (1.2±0.4) was decreased compared with the other two groups (<0.05), while the biochemical pregnancy rate, clinical pregnancy rate and live birth rate in the normal body mass group were higher compared with the other two groups, but the differences showed no statistically significance (all >0.05). Increased BMI might affect ovulation induction response in early follicular phase prolonged protocol IVF/ICSI patients, leading to the increase of Gn dosage and the extension of Gn induction days. Although there is no significant difference in pregnancy outcome among different BMI groups, considering the increased risk of adverse perinatal outcomes during subsequent pregnancy in overweight or obese patients, certain attention should still be paid to the control of BMI in patients receiving assisted reproduction treatment with early follicular phase prolonged protocol.