Early menarche: A systematic review of its effect on sexual and reproductive health in low- and middle-income countries

Background
Adolescent girls aged 15–19 bear a disproportionate burden of negative sexual and reproductive health outcomes in low- and middle-income countries. Research from several high-income countries suggests that early age at menarche is an important determinant of sexual and reproductive health. We conducted this systematic review to better understand whether and how early menarche is associated with various negative sexual and reproductive health outcomes in low- and middle-income countries and the implications of such associations.
Methods
We systematically searched eight health and social sciences databases for peer-reviewed literature on menarche and sexual and reproductive health in low- and middle-income countries. Two reviewers independently assessed all studies for inclusion, overall quality and risk of bias, and performed data extraction on all included studies.
Results
Twenty-four articles met all inclusion criteria–nine of moderate quality and fifteen with several methodological weaknesses. Our review of the minimal existing literature showed that early menarche is associated with early sexual initiation, early pregnancy and some sexually transmitted infections in low- and middle-income countries, similar to what has been observed in high-income countries. Early menarche is also associated with early marriage–an association that may have particularly important implications for countries with high child marriage rates.
Conclusions
Early age at menarche may be an important factor affecting the sexual and reproductive health of adolescent girls and young women in low- and middle-income countries. More research is needed to confirm the existence of the identified associations across different settings and to better understand the process through which early menarche and other markers of early pubertal development may contribute to the increased vulnerability of girls to negative sexual and reproductive health outcomes in low- and middle-income countries. Given the association of early menarche with early marriage, ongoing efforts to reduce child marriage may benefit from targeting efforts to early maturing girls.

研究背景
15至19岁的青春期少女在中低收入国家中承受着不成比例的不良性与生殖健康结局负担。多项高收入国家的研究表明，初潮（menarche）年龄偏早是性与生殖健康的重要影响因素。我们开展本次系统综述，旨在明确中低收入国家中初潮年龄偏早是否与各类不良性与生殖健康结局存在关联，以及此类关联的具体作用方式与相关影响。

研究方法
我们系统检索了8个健康与社会科学数据库，查找关于中低收入国家初潮与性及生殖健康的同行评议文献。由2名评审员独立评估所有候选研究的纳入资格、整体质量与偏倚风险，并对所有纳入研究完成数据提取。

研究结果
共有24篇文献符合全部纳入标准，其中9篇质量中等，15篇存在若干方法学缺陷。针对现有少量相关文献的综述结果显示，在中低收入国家中，初潮年龄偏早与过早首次性行为、早孕以及部分性传播感染存在关联，该结论与高收入国家中的观测结果一致。此外，初潮年龄偏早还与早婚存在关联——这一关联对于童婚率较高的国家而言，或具有尤为重要的现实意义。

研究结论
初潮年龄偏早或为影响中低收入国家青春期少女与青年女性性及生殖健康的重要影响因素。未来仍需开展更多研究，以验证上述关联在不同环境中的普遍性，并进一步明确在中低收入国家中，初潮年龄偏早及其他青春期发育提前标志物如何通过相关作用过程，加剧少女面临不良性与生殖健康结局的易感性。鉴于初潮年龄偏早与早婚存在关联，当前旨在降低童婚的干预工作，若将早熟少女作为重点干预目标，或可提升干预成效。