Menstrual cycle characteristics and time to pregnancy: a retrospective cohort of Mexican nurses

Abstract

Objective

To explore the association between menstrual cycle characteristics and Time to Pregnancy (TTP) among nurses.

Methods

A retrospective cohort study was conducted between 2019 and 2023. Based on the total number of nurses at the Health Institute of the State of Mexico, the sample size was calculated, resulting in 378 nurses. The study included 600 participants who agreed to participate and had their first pregnancy within the last 14 years. The variables of interest were collected through a questionnaire, and the data analysis employed a discrete-time analogue of the Cox proportional hazards model.

Results

A significant association was identified between increased TTP and the age at menarche [ORF = 0.80; 95% CI: 0.70–0.92], menstrual irregularity [ORF = 0.54; 95% CI: 0.35–0.85], cycles until menstruation became regular [ORF = 0.43; 95% CI: 0.36–0.52], and moderate [ORF = 0.55; 95% CI: 0.35–0.86] or heavy menstrual bleeding [ORF = 0.26; 95% CI: 0.35–0.70].

Conclusions

Menstrual cycle characteristics are significantly associated with TTP among nursing professionals. These findings highlight the importance of monitoring and understanding menstrual patterns to improve fertility planning and management in this professional group. However, methodological limitations of the retrospective design, such as recall bias, should be considered.