One in eight women and one in ten men have experienced infertility, yet nearly half of them have not sought medical help, according to a study of more than 15,000 women and men in Britain published in Human Reproduction , one of the world's leading reproductive medicine journals.
The study found that, of those who reported experiencing infertility (defined as unsuccessfully trying to become pregnant for a year or longer), 42.7% of women and 46.8% of men did not seek medical help for the problem. Those who did seek help were more likely to have higher educational qualifications, better jobs and, among those who had a child, to have become parents later, compared with those who did not seek help.
Jessica Datta, a lecturer in the Department of Social and Environmental Health Research at the London School of Hygiene & Tropical Medicine (London, UK), who led the research, said: "We were surprised that almost half of the people in our study who had experienced infertility had not sought help."
Ms Datta and her colleagues analysed data from 15,162 women and men aged between 16 and 74 years who took part in Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3) between 2010 and 2012.
They found that the prevalence of infertility was highest among women aged 35-44 years and among men aged 35-54. More than a third of women who became mothers aged 35 or older had experienced a period of infertility compared to fewer than one in ten women who had their first child before the age of 25.
Infertility was most likely to be experienced by people who were married or cohabiting at the time they were interviewed for the study, probably reflecting the fact that those in stable relationships were more likely to have attempted pregnancy and therefore become aware of fertility problems. Experience of infertility was more common among people with higher socio-economic status, including women who had a university degree and both women and men in managerial, professional or technical employment, compared to people in lower status, routine occupations.
Ms Datta said: "One of the important and concerning findings in our study is the difference in educational attainment and job status between people who sought help for infertility and those who did not. Studies of infertility have tended to recruit research participants from medical settings such as general practice, so our population-based survey sample provides a rare insight into those people who, despite having failed to get pregnant after a year of trying, did not seek help from health services. The existence of inequalities in access to healthcare is well established but this is one of few analyses to explore uptake of services for infertility."
Drawing on findings from other studies, the researchers suggest that possible reasons for the inequalities between those who did and did not seek help for infertility include not understanding or acknowledging that a problem exists, fear of being labelled infertile, concerns about the cost of treatment, the physical and psychological burden of treatment, or simply not wanting to get pregnant.
Ms Datta said: "Our research has implications for women pursuing careers in an uncertain labour market. Rather than warning them of the risks to fertility of delaying parenthood, we advocate social policy that better supports working parents to manage the responsibilities of employment and bringing up children."
Although the study was conducted in a British population, the researchers believe that similar results could be found in other countries but that different definitions of infertility and of study populations mean it can be difficult to make comparisons.
The study also found that women aged 50 or younger who had experienced infertility were more likely to have symptoms of depression and feel dissatisfaction with their sex life than those who had not. These associations were not observed for men.
Ms Datta said: "Previous research has found associations between undergoing treatment for infertility and sexual dissatisfaction. In our study, symptoms of depression occurred in the two weeks before interview and sexual dissatisfaction in the year before interview but, as we don't know when the period of infertility occurred, we cannot make assumptions about causality and are in favour of further investigation into the long term impact of infertility on women's well-being."
 "Prevalence of infertility and help seeking among 15 000 women and men," by J. Datta et al. Human Reproduction journal. doi:10.1093/humrep/dew123.
 The study was carried out by the London School of Hygiene & Tropical Medicine and University College London.
 Natsal-3 was funded by the UK's Medical Research Council and The Wellcome Trust, with additional funding from the UK Economic & Social Research Council and the UK's Department of Health.