Underlining the growing infertility rate among Indian couples, a nine-city survey has found that 46% of the couples who landed up at infertility clinics belonged to the prime reproductive age group of 31 to 40. Of them, 49% had already undergone IVF or in vitro fertilization, a treatment for infertility.

When infertility experts were consulted in a parallel survey, they said 63% of couples seeking treatment were in the 31-40 age group. The survey by a pharmaceutical company interviewed 2,562 people who visited 100 clinics of doctors or attended patient camps . Infertility is defined as the inability to conceive after two years of trying for a baby.

"It is believed that 10% of the general population suffers from some form of infertility . Given that India has a population of over 1.2 billion, the number of Indians suffering from infertility is huge," said Dr Jaideep Malhotra, the president-elect of the Asia Pacific Initiative on Reproduction , while presenting the survey results on Thursday.

Stating statistics released by the World Bank in 2013, the doctors said the decline in fertility started a decade ago, with a 17% drop since 2000.

Infertility experts, who are part of the India Society for Assisted Reproduction (ISAR) that has endorsed the survey, said lifestyle factors were contributing to the increase in infertility.

Among males, 41% infertility is due to problems concerning sperm (oligospermia or poor sperm count). In females , 40% is attributed to poly cystic ovarian disorder (PCOD), said ISAR presidentelect Dr Hrishikesh Pai.

He added that the increased levels of estrogen in the environment due to contaminated food had led to a drop in sperm count across the country . "Among younger women, we are seeing poor ovarian reserve (the capacity of the ovary to produce eggs)." There are no concrete reasons at present for this trend.

Moreover, Indians rarely sought treatment on time. "The problem is that couples would rather derive information from the internet and friends than go to a doctor," said Dr Malhotra.

The doctors said they were disturbed with the survey's finding that 64% of the people still believed that the birth of a child is God's will and, hence, delayed treatment.