Menstrual disorder is associated with blood type in PCOS patients: evidence from a cross-sectional survey.

Background: Previous studies have shown a correlation between ABO blood type and the occurrence of certain diseases. However, there is limited research on the potential association between ABO blood group and polycystic ovary syndrome (PCOS). This study aims to investigate the potential connection between ABO blood type and the regularity of menstrual cycles, menstrual bleeding level, and additional metabolic indicators among individuals diagnosed with PCOS.

Methods: This cross-sectional study involved 312 PCOS patients and 133 healthy controls whose menstruation and blood type were investigated by questionnaires. Their blood lipid content and hormone levels were also measured. We assessed the association between ABO blood type distribution in different groups and the occurrence of menstrual conditions in PCOS patients.

Results: 445 women participated in the study. There was a statistically significant difference in ABO blood type distribution among PCOS patients with varying menstrual levels (P = 0.036). Compared with other blood type groups, PCOS patients with blood type O exhibited statistically significant differences in BMI (P = 0.033), E2 levels (P < 0.001), LH levels (P = 0.022), and FSH levels (P < 0.001), and showed a higher tendency towards greater menstrual bleeding.

Conclusion: There exists a correlation between ABO blood type and menstrual bleeding level among PCOS patients. In particular, individuals with blood type O display a heightened likelihood of experiencing greater menstrual bleeding with more favorable endocrine status compared to non-O blood types in the population.

Clinical trial registration: ClinicalTrials.gov NCT04264832 ( https://clinicaltrials.gov ). Registered on February 7, 2020.