How Do Contraceptives Affect Inter-Birth Intervals? An Empirical Inquiry Using Contraceptive Calendar

Syeda Naz, East Tennessee State University

This study explores the effect of contraceptive use on the risk of subsequent pregnancy to study the impact of contraceptive use on birth interval duration. The analysis compares the risk of pregnancy in multiple birth intervals with and without contraceptive use for the same mother using mother fixed effects. The analysis is based on 12,540 birth intervals from the reproductive calendar data provided by the Pakistan Demographic and Health Survey 2017-18. Using an event-history analysis and using birth interval duration (in months) as an outcome variable, the analysis finds that every additional month of contraceptive use within a birth interval reduced the risk of pregnancy by 25%. The heterogeneity analysis suggests that the log hazard of pregnancy was lowest among IUD users, followed by injectable, withdrawal, pill, and condom, respectively. The analysis also finds suggestive evidence that, in this context, a traditional family planning method withdrawal is more effective in lengthening birth intervals than two modern contraceptives: birth control pills and condoms. These results highlight the need to focus on the optimal use of modern contraceptives to help reduce the short birth intervals which can be attained through the quality of care in family planning services.

Keywords: Family Planning and Contraception

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