Related Experiment Video
Updated: May 29, 2026
A Modified Technique for Inducing Polycystic Ovary Syndrome in Mice
Published on: July 5, 2024
Body mass index-associated differences in response to ovulation induction with letrozole
Katherine K McKnight1, James L Nodler, John J Cooper
1Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Alabama, Birmingham, Alabama, USA. kkmcknight@gmail.com
Objective:
To compare occurrence of pregnancy among obese (body mass index [BMI] ≥30) and nonobese (BMI <30), infertile women undergoing ovulation induction with the aromatase inhibitor letrozole followed by intrauterine insemination (IUI).
Design:
Retrospective cohort study.
Setting:
Academic reproductive endocrinology and infertility clinic.
Patient(S):
Ninety women with a variety of infertility diagnoses.
Intervention(S):
Letrozole (5 mg) on menstrual cycle days 3-7, followed by intrauterine insemination (IUI).
Main Outcome Measure(S):
Occurrence of pregnancy and pregnancy outcomes.
Result(S):
Ninety women underwent 180 letrozole-IUI cycles. Conception of pregnancy occurred in 10.4% and 18.2% of the BMI <30 and BMI ≥30 groups, respectively. Using BMI as a continuous variable showed a pregnancy odds ratio of 1.093 (confidence interval 1.008-1.184) for each unit increase in BMI. Incidence of miscarriage, multiple births, number of mature follicles, and presence of LH surge were similar between groups.
Conclusion(S):
Our study of 90 women undergoing letrozole-IUI treatment showed greater likelihood of pregnancy in higher-BMI women, although the difference was not significant. Letrozole is an effective ovulation induction agent in higher-BMI women.
Related Concept Videos
01:30Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
01:27Ovarian Cycle
01:22Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
02:07Oogenesis
01:28Infertility in Females
Endometriosis, a condition characterized by abnormal growth of endometrial...
01:23Infertility in Males