A US Government report shows that six percent of married couples in the USA have problems conceiving, down from 8.5 percent in a similar report three decades ago.
From 2006 to 2010, The National Center for Health Statistics carried out more than 22,600 phone interviews with men and women aged between 15 to 44 as part of the National Survey of Family Growth. The report aims to provide a demographic snapshot and help predict the demand for infertility-related medical services.
'When you look at this downward trend, it goes against popular wisdom', lead author Dr Anjani Chandra, a heath scientist at the National Center for Health Statistics, told USA Today.
For the purposes of the report, infertility is defined as the 'lack of pregnancy in the 12 months prior to the survey, despite having had unprotected sexual intercourse in each of those months with the same partner'.
Use of IVF treatments has doubled in the USA over the last decade, while treatments involving donor gametes or surrogacy have also become more common. However, biology has not changed, and Dr Chandra says that this greater availability of fertility treatments may be a crucial factor in bringing the rate of infertility down. 'The level of infertility is being counteracted by [people's] pursuit of medical help to have a child', she said.
Unsurprisingly, the report confirmed that infertility is more common in women in their late 30s and early 40s. No significant infertility differences were found between white, black and hispanic women. But the data do suggest that having one child increases the likelihood that an older woman is capable of becoming pregnant again.
'When we're looking at people who have had a child, behavioural aspects like smoking and sexually transmitted diseases that impeded their primary infertility may have been corrected', Dr Chandra suggests.
Summing up the findings, Professor Richard Reindollar, president-elect of the American Society for Reproductive Medicine, told USA Today he found the report encouraging: 'Even though the ages at which women in the United States have their children have been increasing since 1995, the percentage of the population suffering from infertility or impaired fecundity has not increased'.