Time to Resumption of Menses, Spatial Distribution, and Predictors Among Post-partum Period Women in Ethiopia, Evidence From Ethiopian Demographic and Health Survey 2016 Data: Gompertz Inverse Gaussian Shared Frailty Model

The timing of the resumption of post-partum menses is important for a woman who intends to avoid subsequent unintended pregnancy, and it has key implications on maternal, neonatal, and child health outcomes. Despite this, information is scant about the time to resumption of post-partum menses and predictors in Ethiopia. Therefore, this study aimed to determine the time it takes to start menses and spatial distribution among post-partum period women in Ethiopia and identify its predictors.

A secondary data analysis was conducted based on 2016 Ethiopian Demographic and Health Survey (EDHS). A total weighted sample of 6,489 post-partum women was included in the analysis. STATA 14 was used to weigh, clean, and analyze the data. The shared frailty model was applied since the EDHS data have a hierarchical nature. For checking the proportional hazard assumption, the Schenefold residual test, Log-Log plot, Kaplan-Meier, and predicted survival plot were applied. Akakie Information Criteria (AIC), Cox-Snell residual test, and deviance were used for checking model adequacy and for model comparison. Based on these, the Gompertz inverse Gaussian shared frailty model was the best-fitted model for this data. Variables with a p < 0.2 were considered for the multivariable Gompertz inverse Gaussian shared frailty model. Finally, the adjusted hazard ratio (AHR) with a 95% confidence interval (CI), and a p < 0.05 was reported to identify the significant predictors of time to the resumption of post-partum menses.

The median survival time to post-partum menses resumption was 14.6 months. In this study, 51.90% [95% CI: 50.03, 53.76] of post-partum period women had resumed, and the risk of menses resumption was 1.17 times [AHR: 1.17; 95% CI: 1.03-1.33] higher among urban resident, 1.14 times [AHR: 1.14; 95% CI: 1.0-1.24] in women who had attended formal education, and 1.63 times [AHR: 1.63; 95% CI: 1.4-1.7] higher among women who used hormonal contraceptives. However, the risk of post-partum menses resumption was lower among 7-24 months breastfeeding women by 36% [AHR: 0.64; 95% CI: 0.5-0.76], women with child alive by 26% [AHR: 0.74; 95% CI: 0.6-0.85], and multiparous women by 27% [AHR: 0.73; 95% CI: 0.6-0.80].

Almost half of the participants had resumed post-partum menses, with the median survival timing of menses resumption at 14.5 months. Women residing in urban areas, who attended formal education, and using hormonal contraceptives have a shorter time to resume post-partum menses, whereas a woman with an alive child, breastfeeding practice, and multiple parity has a longer time to resume post-partum menses. Therefore, the healthcare providers and program managers should act on the resumption of post-partum menses through health education and promotion to cultivate the 14 months lag period identified by considering the significant factors.