Letrozole with FSH had similar pregnancy rates in obese and nonobese PCOS women, claims research

Higher body mass index is associated with infertility, especially
ovulatory disorders. Obese women under treatment for infertility may face
additional problems, such as the need for higher doses of drugs to induce/stimulate
ovulation, oocyte morphological changes, reduction in fertilization and
implantation rates, and embryo quality.

Letrozole and clomiphene citrate are commonly used drugs for
ovulation induction with or without gonadotropins in anovulatory women especially
polycystic ovarian syndrome. Letrozole, a short half-life aromatase
inhibitor(45 hours), has shown more successful ovulation induction in
polycystic ovarian syndrome (PCOS) patients.

In cases of poor follicular response, low doses of FSH are
given as a cotherapy with letrozole to enhance follicular development and
maturity. Letrozole cotreatment with gonadotropins was found to cause a higher
incidence of monofollicular growth which is an advantage that reduces the risks
of hyperstimulation effect of ovulation induction therapy. Letrozole was also
used in unexplained infertility and found to be as effective as clomiphene
citrate with reduced multiple births. However, a combination of letrozole and
gonadotropins has not been studied extensively either in PCOS patients or
unexplained infertility, in relation to obesity. Therefore, the goal of this
study was to assess the success of ovulation induction with letrozole combined
with FSH in obese and nonobese women. The main intention was to study the
impact of obesity on fertility outcome, when FSH was used along with letrozole.

A retrospective descriptive cohort study was conducted
involving 135 women who underwent OI with letrozole plus follicle stimulating
hormone therapy and either timed intercourse or intrauterine insemination. The
data was collected from the hospital information system, including the age,
body mass index, the type of infertility, number of induction cycles with
letrozole, number of gonadotropin injections, and the pregnancy occurrence
following treatment. SPSS was used to analyze the data

There were 135 women who used FSH injections along with
letrozole. Of this, 28.5% obese women got pregnant compared to 29.2% nonobese
women, but this did not attain statistical significance (P = 0:75). About 70%
of obese women and 57% on nonobese women had polycystic ovarian syndrome. The
median number of FSH injections was six, and the interquartile range was 3 to
11.

Women with BMI 30 were more likely to conceive with
letrozole and FSH. It is hypothesized that letrozole decreases the conversion
of testosterone to estrogen peripherally, thus decreasing pituitary inhibition,
and promotes normal secretion of gonadotropins. However, in view of obesity,
these women needed more FSH. The dose of FSH injections did not differ
significantly between obese and nonobese women in our study. According to Kaya
et al., increased BMI was associated with the increase in FSH requirement and a
longer period of ovarian stimulation that could result in follicle development.
The number of follicles also did not differ significantly between the obese and
nonobese women in this study.

In conclusion, in the small number of women authors studied,
letrozole and FSH were equally effective and there was not a single woman with
ovarian hyperstimulation.

Source: Vaidyanathan Gowri , 1 Arwa Al-Amri,2 Thikra
Mohammed Abdulrahman Almamari; Hindawi International Journal of Reproductive
Medicine Volume 2022, Article ID 1931716, 4 pages https://doi.org/10.1155/2022/1931716