Value of follicular output rate in predicting ovarian response and pregnancy outcome of infertile patients

Abstract

Objective To investigate clinical values of follicular output rate (FORT) in predicting ovarian response and pregnancy outcome of infertile patients with in vitro fertilization and embryo transfer (IVF-ET). Methods From January 1, 2010 to December 31, 2014, a total of 768 infertile patients who were treated with IVF-ET in Reproductive Medicine Center of Zhongnan Hospital of Wuhan University were collected as research subjects. In this study, FORT was the ratio of the number of preovulatory follicles (PFC) with a diameter of 3 to 8 mm and the antral follicle count (AFC) of 14 to 22 mm on the day of human chorionic gonadotropin (hCG) injection. According to FORT value, they were divided into 3 groups, low FORT value group (n=255, FORT value was lower than the 33rd percentile of the FORT value of all subjects, i. e. FORT value 0.67). The general clinical data and related indicators of controlled ovulation hyperstimulation of 3 groups were collected by retrospective analysis. The age, body mass index (BMI), basal follicle stimulating hormone (FSH), AFC, total amount of gonadotropin (Gn), Gn use days, estradiol level on the day of hCG injection, PFC, number of ovums obtained, number of MⅡ ovums and number of embryos transferred were analyzed by one-way ANOVA analysis. The least significant difference(LSD) method was used to analyze AFC among three groups in further pairwise comparison. The duration of infertility, basic luteinizing hormone (LH) and basal estradiol levels were analyzed by Kruskal-Wallis H rank sum test. Chi-square test was used to analyze the ratio of different causes of infertility, high-quality embryos rate, embryo implantation rate, clinical pregnancy rate and live birth rate. Pearson correlation analysis was used to analyze the correlation between FORT and number of ovums obtained, number of available embryos, number of high quality embryos, age, basal FSH level and basal estradiol level, respectively. Influencing factors of clinical pregnancy rate in infertile patients were analyzed by multivariate unconditional logistic regression analysis. The procedures followed in this study were approved by the Ethics Committee of Zhongnan Hospital of Wuhan University (Approval Number: 2017109). Results ①There were no significant differences among three groups in age, BMI, infertile duration, ratio of causes of infertility and other general clinical data (P>0.05). ② There were no significant differences in basal FSH, basal LH and basal estradiol levels among three groups (P>0.05). The number of AFC of low, middle and high FORT value group groups were 15.2±3.2, 14.3±3.7 and 13.8±3.5, respectively, and the difference was statistically significant (F=56.547, P 0.05). ④Among all the infertile patients in this study, FORT had positive correlation with the number of ovums obtained (r=0.286, P<0.001), number of available embryos (r=0.327, P<0.001) and number of high quality embryos (r=0.252, P<0.001), but FORT had no correlation with age (r=0.021, P=0.063), basal FSH level (r=—0.019, P=0.169), basal estradiol level (r=0.023, P=0.088). ⑤ The results of multivariate unconditional logistic regression analysis on influencing factors of clinical pregnancy rate of infertile patients showed that FORT was the independent influencing factor on the clinical pregnancy rate of infertile patients (OR=1.023, 95%CI: 1.003-1.043, P=0.027). Conclusions FORT can be used as an effective index to predict ovarian antral follicles′ response to FSH and pregnancy outcome of infertile patients. However, because this study is just a retrospective study, the value of FORT in predicting ovarian response and pregnancy outcome in infertile patients remains to be confirmed by large, multicenter, prospective studies. Key words: Fertilization in vitro; Embryo transfer; Follicular output rate; Ovarian response; Controlled ovarian hyperstimulation; Pregnancy outcome; Antral follicle count; Preovulatory follicle; Infertility, female