Serum leptin level in Sudanese women with unexplained infertility and its relationship with some reproductive hormones.

Background: The excessive concentration of leptin has negative effects on all aspects of female reproduction. Despite this established relationship, the exact role of leptin in women's fertility is not clear enough and needs more clarification.

Aim: To evaluate the serum leptin levels in Sudanese women and to ascertain the relationship between serum leptin levels and unexplained infertility (UI).

Methods: A matched (age and body mass index) case-control study was conducted from March 2021 to February 2022. The study samples were 210 women with UI and 190 fertile women of reproductive age who were attending the maternity hospitals and fertility clinics in Khartoum state Sudan. The serum concentration of leptin and other serum biomarkers were determined using enzyme-linked immunosorbent assays.

Results: The results showed that there was a highly statistically significant difference between the two groups (P < 0.001) for all examined eight biomarkers. Whereby, leptin, luteinizing hormone (LH)/follicular stimulating hormone (FSH) ratio, prolactin hormone (PRL) and testosterone (T) were significantly higher in the UI group compared with the control group. In contrast, FSH and estradiol (E2)/T ratio were significantly lower in the UI group than in the control group and the effect size test for the difference between the two groups was very large (effect size > 0.80), for leptin level, LH/FSH ratio, PRL level, and E2/T ratio, and large (effect size 0.50- ≤ 0.80) for FSH and T.

Conclusion: This study reveals that leptin could be a potential biomarker for UI in Sudanese women and it may be useful for identifying women with a high risk of infertility.