New Delhi: Bihar, Madhya Pradesh, Rajasthan and Uttar Pradesh, previously known as the Bimaru states, have registered falling fertility rates in the age group of 15-24, especially in rural areas, over the past 15 years.

Delayed marriage on account of increased enrolment of rural women in this age group in educational institutions is a major reason for this shift in these states, which are now known as “major high focus states", demographers said.

To be sure, fertility rates in these states have also declined in urban areas, though this fall has not been very sharp, according to data from the latest Sample Registration System (SRS), which defines fertility rate as the number of live births per year per 1,000 women.

These states were first dubbed Bimaru 36 years ago based on some key indicators like the average age at marriage, fertility rate, family planning, maternal and infant mortality rates and life expectancy at birth.

According to the SRS, fertility rates in rural Bihar in the age group of 15-19 years have declined to 19.6 in 2014 from 56.8 in 2001 and in the age bracket of 20-24 years to 220.2 in 2014 from 255.6 in 2001.

In case of Madhya Pradesh, fertility rates have halved to 45.1 for the age bracket of 15-19 years. In Rajasthan and Uttar Pradesh, fertility rates have declined to 46.3 and 25.7 in 2014 from 60.3 and 40.8 in 2001 in 15-19 years age group.

“There has been a sizeable decline in fertility rates in the first two reproductive age groups since 2001 in all these four major high focus states, but further decline is still very much desirable, especially in the rural areas," said Chander Shekhar, department of fertility studies, International Institute for Population Sciences.

“It’s been seen that the declining fertility rates are found to be associated with increase in proportion of unmarried women in these two particular age groups," he said.

According to the 2011 census, Rajasthan and Bihar had the least proportion of unmarried women in the two categories across all states.

The highest proportion of unmarried women within Bimaru was in Madhya Pradesh in the age group of 15-19. The state saw a 17 percentage point rise in unmarried women from 2011. Unmarried women in the age bracket of 15-19 years increased by 15 percentage points each in Bihar, Rajasthan and Uttar Pradesh.

On the other hand, in the age bracket of 20-24, the unmarried women population increased by 15 percentage points in Uttar Pradesh, 10 percentage points in Madhya Pradesh, 8 percentage points in Rajasthan and 6 percentage points in Bihar.

The increase in the number of unmarried women is also linked to a sharp rise in the number of women attending educational institutions, suggesting that states need to step up efforts to enhance enrolment in secondary and above levels in the first two reproductive age groups so that they can reap the social and health benefits of postponement of marriage.

Demographers hope that these trends in the proportion of single women would eventually not only lead to a reduction in fertility rates, but also reduce the risk of child and mother’s health especially in the 15-19 years age group.

Shekhar added that the most efficient way to expedite a further decline in fertility rate in these two initial reproductive age groups is to reduce the dropout rate among girls at the secondary and above levels and to create job opportunities that do justice to their educational levels.

Access to high-quality family planning services is also an effective way, he added.