Delay in the Second Birth: An Analysis of the Length of Waiting Time from First to the Second Birth among Women in the City of Khorramabad, Iran

Postponment of first birth to the older age of the mothers, as well as lengthening the birth intervals, has been a part of Iran's experience of low fertility during last two decades. In fact, postponement of successive births for extended periods accounted for much of the drop in Iran’s fertility to below replecemetn level. The purpose of this study is to estimate the survival time of single child and its determinants in Khorramabad city. Data was collected using a survey questionnaire in a sample size of 478 married women aged 15-49 in 2021. The Kaplan-Meier test was used to determine the second birth interval. To investigate the effect of independent variables on survival time, the lognormal parametric model with common fragility model was used. The findings showed that the median survival time of single child is 60 months. Women with university education, with a modern gender attitude, women with a limited social network and a high sense of socioeconomic insecurity, have a second child later than other women, so they have a higher probability of being as a single-child mothers. Clearly, the timing of births needs basic attention at the level of policy and planning. Therefore, in line with the current population policies, it is necessary to implement programs to facilitate childbearing and support people who desire to have children, but due to opportunity costs or socio-economic limitations, they may remain single child for a long time.