Duration and determinants of birth interval in Yazd, Iran: a population study

Background: Short birth intervals have been associated with adverse health outcomes, including infant, child and maternal mortality. Objective: We aimed to investigate the duration and determinants of inter birth intervals among women of reproductive age in Yazd, Iran. Materials and Methods: A cluster sampling technique was used to select 400 ever-married women aged 15-49 years in Yazd, Islamic Republic of Iran. Data were obtained by interview questionnaire and analyzed with life table, Kaplan-Meier survival and Cox regression analyses. Results: The mean duration of inter birth interval was 49.76 (standard error 1.82) months (95% CI: 46.19-53.34 months) with a median of 39. In 28.5% of women the birth interval was <2 years, in 28% it was 3-5 years and in 25.5% it was ≥6 years. Among explanatory variables of interest, age of marriage, and woman's education were significant predicators of the birth interval. Women who stated an ideal preference of two children constituted 59.9% of the sample and 16% had 3 children as well as 10.7% had an ideal preference for 4 or 5. Conclusion: The study recommended an educational program to have optimal birth intervals and ideal number of children per family for the prevention of adverse prenatal outcomes.