Relation between the Number and Size of Follicles in Ovulation Induction and the Rate of Pregnancy

Abstract

Objective: The aim of this study was to investigate the relation between number and size of preovulatory follicles and the outcome of controlled ovarian hyperstimulation (COH) and intrauterine insemination (IUI) in cases of unexplained infertility. Subjects and methods: This prospective study included 200 couples with unexplained infertility. They were submitted to COH with clomiphene citrate and hMG followed by hcg when at least one growing follicle reaches the size of >18mm follicular monitoring started on the 10th day of the cycle until at least one follicle reaches 18mm or more. We recorded the highest follicular count of different diameters in the two ovaries during the days preceding hCG injection. Growth of more than one follicle with a diameter of >18mm is considered multifollicular growth. IUI was performed with fresh sperm 24 to 36 hours after hCG administration to a maximum of three cycles. The primary outcome measure was achieving pregnancy confirmed by rising hCG levels. Results: Eighteen couples were excluded from the study. Clinical pregnancy occurred in 42 cases (23.1%). Significantly higher pregnancy rates were achieved in younger females (73.8%) and in those with duration of infertility <5 years (28.6%).Pregnancy rate increases significantly with more follicles >12mm or >15mm,but not with number of follicles >18mm. Pregnancy rate was significantly higher in cases with multifollicular growth. Conclusion: In couples with unexplained infertility treated with IUI, pregnancy rate was positively associated with multifollicular growth and higher number of >12mm or > 15mm