Objective: The aim of the study was to systematically review and meta-analyze the available data on changes in the hormonal profile of postmenopausal women treated with hormone replacement therapy (HRT).
Materials and methods: Full-text articles published up to April 30, 2021, were searched through PUBMED, EMBASE, the Cochrane library and Web of Science (WOS) databases and were screened strictly according to inclusion criteria. Randomized clinical trials and case control studies were enrolled. Studies not reporting steroid serum levels or not providing a control group were excluded from the analysis. Studies enrolling women with genetic defects or severe chronic systemic diseases were excluded. Data are expressed as standardized mean differences (SMDs) with 95% confidence intervals (CIs). Random effect models were used for the meta-analysis.
Results: HRT administration increases estradiol (E2) and reduces follicle stimulating hormone (FSH) serum levels compared with pre-treatment. Their changes are evident when oral and transdermal HRT are administered, while vaginal HRT not. No significant effect on E2 and FSH was found between 6 and 12 months, as well as between 12 and 24 months. No significant effect on E2 and FSH was shown between different regimes. No difference was observed between different HRT regarding their effect on lipid profiles, breast pain and vaginal bleeding, but oral estrogen combined synthetic progestin caused a reduction in sex hormone-binding globulin (SHGB).
Conclusions: The review suggested oral and transdermal HRT could lead to a rise in E2 serum levels and a decrease in FSH. The types and doses of HRT did not seem to modify the E2 and FSH level. Also, oral estrogen combined synthetic progestin could cause a reduction in SHGB. This might be crucial when choosing the best possible treatment for each patient individually taking into consideration if potential benefits outweigh the risks.