The effects of Covid-19 mRNA vaccine on adolescence gynecological well-being

Key message: Menstruation of adolescent girls might be influenced by Covid-19 mRNA vaccine, however, the ovarian reserve estimated by AMH is not compromised. Background: Recent studies have suggested that the acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine causes menstrual abnormalities which led to concerns regarding its influence on the reproductive system. This study aims to investigate the influence of the SARS-CoV-2 mRNA vaccine on gynecologic well-being and future fertility of adolescent girls. Methods: This is a prospective cohort study conducted at a university affiliated medical center between June and July 2021. Adolescent girls aged 12–16 years who were vaccinated by two Pfizer-BioNTech Covid-19 vaccines (21 days apart) were included in the study. All participants completed a computerized questionnaire regarding their general medical and gynecological background at recruitment and 3 months later. Blood samples were collected for AMH levels before and 3 months following the first mRNA vaccine Results: The study group consisted of 35 girls, and of them, follow-up was completed by questionnaire and AMH sampling in 35 (90%) and 22 (56%) girls, respectively. Among the 22/35 girls who reported regular menstruation before vaccination, seven (31.8%) experienced irregularities post-vaccination. Four of the eight pre-menarche girls included in the study reported on menarche on follow-up. Median AMH levels were 3.09 (IQR 1.96–4.82) μg/L and 2.96 (2.21–4.73) μg/L at baseline and after 3 months, respectively (p = 0.07). After controlling for age, BMI and presentation of side effects, no association was demonstrated to the change in AMH levels (AMH2-AMH1). Conclusions: Although menstruation of adolescent girls might be influenced by Covid-19 mRNA vaccine, it seems that the ovarian reserve estimated by AMH is not compromised. Clinical trial registration: National Institutes of Health (NCT04748172).