Changes in age at last birth and its determinants in India

In recent years, developing and developed countries are witnessing delayed childbearing among women contributing to the overall decline in fertility rates. The age at which a woman has her last child impacts maternal and child health, especially in a country with high maternal and perinatal mortality rates. This study aims to investigate the trends of age at the last birth among Indian women and to identify the potential factors contributing towards higher maternal age. The present study uses the data from five consecutive rounds (1992–1993, 1998–1999, 2004–2005, 2015–2016, and 2019–2021) of the National Family Health Survey (NFHS). We have used descriptive statistics, bivariate, Cox proportional hazard regression analysis, multiple classification analysis (MCA), Kaplan–Meier curve, life table survival analysis, hierarchical clustered heat map, multivariate decomposition analysis (MDA) and geospatial mapping to fulfill the objective of the study. Results show that the proportion of women with age at last birth before reaching the age of 30 years was less than half (nearly 35%) during NFHS-I while during NFHS-V proportion becomes more than half and reaches 64.3% among 40–49 years women. Within three decades (1992–2021) there has been a decline of 15.8% in median age at last birth among women aged 40–49 years. Additionally, the highest percentage decline in predicted mean age at last birth was noted among individuals from rural area (10.7%, 3.3 years), Hindu religion (10.8%, 3.3 years), poor wealth quantile (12.5%, 4.0 years) and those with mass media exposure (10.6%, 3.2 years) from NFHS-I (1992–1993) to NFHS-V (2019–2021). Although there exists the need to delay age at first childbirth, the age at last childbirth also plays an important role in women’s and child health status. Hence, it is important to address the healthcare needs of those delaying their childbirth.