Menstrual Patterns in the First Gynecological Year: A Systematic Review.

STUDY OBJECTIVE: Understanding what constitutes a normal menstrual cycle during the first gynecological year (GY1) is a common concern of adolescents and clinicians. However, limited high-quality evidence exists. We aimed to summarize published literature regarding menstrual and ovulatory patterns in GY1. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Electronic databases (MEDLINE, Pre-MEDLINE, Embase, Web of Science, CINAHL, Cochrane Library) were systematically searched from database inception to 2018. Eligible studies described menstrual cycles, symptoms, or validated ovulatory data in healthy adolescents in GY1. Two authors independently screened studies, extracted data, and assessed methodological quality.

RESULTS: Twenty-two studies involving more than 2000 adolescents were included. Thirteen recorded menstrual cycle and/or symptom data and 14 measured ovulation. Mean cycle length ranged from 32 to 61 days and decreased throughout GY1. Mean menses length was 4.9 to 5.4 days. Frequent menstrual bleeding was reported in up to 23% of participants, infrequent menstrual bleeding in up to one-third, and "irregular menstrual bleeding" in up to 43%. Dysmenorrhea was reported by 30%-89% of participants. Prevalence of ovulatory cycles identified using luteal phase serum or salivary progesterone or urinary pregnanediol was 0 to 45% and increased throughout GY1. However, all used definitions that would be considered subovulatory in clinical practice.

CONCLUSION: Menstrual and ovulatory patterns in GY1 are diverse and differ from those of adults. A transitional phase of menstrual and ovulatory immaturity is common. However, ovulation, irregular cycles, and dysmenorrhea are not uncommon. As such, safe sexual practice should be advocated and prompt medical management should be accessible.