Study of menstrual cycle synchrony in female medical students sharing common accommodation

Menstrual cycle synchronization is a phenomenon in which menstrual onset shifts progressively closer with time. It is an adoptive conditional phenomenon seen in the females who associate closely and share a common environment.

To ascertain whether menstrual cycle synchrony exists in the roommates living in a closed space in a medical hostel.

This is a prospective observational study comprising 62 female medical students of a mean age of 22 years living in twin sharing accommodation with a history of regular menses (26-32 days).

These participants were followed on a monthly basis for 13 months. Menstrual cycle history was obtained using standardized Google forms. Menstrual cycle initial and final onset differences, expected cycle cut-off values, and absolute differences were calculated. The menstrual cycle synchrony score was obtained by subtracting the expected difference from the onset difference. Wilson's absolute difference method was used for determining menstrual synchrony between pairs.

The descriptive analysis was done using mean and standard deviation. One sample t-test was used to assess the synchrony between roommates. P value ≤0.05 was considered as statistically significant.

The initial onset difference of the menstrual cycle was 7.58 ± 4.25 days, whereas the final onset difference was 6.06 ± 3.92 days. The calculated synchrony score was -9.28 ± 5.05, which was statistically significant. Menstrual cycle synchrony was observed in 17 pairs (54.8%) and asynchrony in eight pairs (25.8%).

Long-term association between roommates has potential to cause menstrual cycle synchrony. It has significant implications in reproductive medicine for reproductive scheduling and family planning.