Marriage to First Birth Interval; A Cross-Sectional Study in Tehran (Iran)

Objectives: One of the features of fertility below replacement level is the increase of the first birth interval which has occurred at the same time with the rise of women's marriage age in recent years in Iran. Since determination of factors affecting delay in childbearing can provide convenient approaches to prevent fertility decline, the aim of this study was to evaluate socio-economic factors influencing the first birth interval in married women in Tehran province, Iran. Materials and Methods: In a cross-sectional study, 610 married women aged 15 to 49 years were selected by the stratified random sampling and a structured questionnaire was used in 2017. Women's first birth intervals were compared in terms of some demographic and socio-economic factors by Kaplan-Meier (KM) estimates and Log-Rank test for univariate and Cox model for multivariate survival analysis using SPSS version 22.0. Results: The mean of women's first birth intervals was 3.181 +/- 0.101 years. Women's educational level and social insecurity had significant effects on the first birth interval (P value <0.05). By increasing educational level and social insecurity, the first birth interval also increased. Women with "secondary and high school" and "MS and PhD" educational levels had the shortest and longest first birth intervals, respectively. Conclusions: According to results, unless governments provide the condition of social security, reducing the interval between marriage age and childbearing will not be attained.