The study shows while 35% women surveyed in 1992-93 had completed bearing children by 30, by 2019-21, this proportion went up to 64%.
Interestingly, the proportion of women who ended childbearing by 40 was slightly lower in 2019-21 than in the previous two NFHS.
One of the authors of the study, Chander Shekhar explained that this was due to two reasons.
First, with women often having the first child at an older age than in the past, in cases where they have more than one child, the second child would also come later.
Also, with fertility treatment becoming more common, child birth could happen late since the treatment can take time.Though the mean age at last birth ranged from 26 years in Tamil Nadu to 33 years in Meghalaya during NFHS-III (2004-05), in the next two surveys, Andhra Pradesh had the lowest (about 25) and Meghalaya (over 30) showed the highest mean age at last birth.The study found that the age at last birth was higher among women who got married before 15 years of age, women who had a higher number of births where pregnancies lasted at least 24 months, and among Muslim women."Pressure to have a child immediately after marriage and little control over their reproductive rights among uneducated women leads to higher rates of unintended pregnancies and continued childbearing at higher ages," stated the study noting that even women with low levels of education had better access to and knowledge about contraception.
Studies based on labour-force participation and fertility indicate that women with long work histories bear children later than those with little or no work experience, it added.
Over the last 30 years, India has witnessed a shortening of women's reproductive period as they are ending childbearing at an earlier age than they did in the past.
A comparison of data from the first National Family Health Survey (NFHS) in 1992-93 with the latest (2019-21) shows that a little under 11% of women in the 40-49 age group had children beyond the age of 40, while 30 years ago, that proportion was over 23%.
The median age at birth has declined by five years, from 33 years to 28 years, over the same period.
The study by researchers of the International Institute for Population Studies, which conducts the NFHS, was published recently in the journal 'Nature'.