Infertility is the term used to describe a couple’s failure to conceive, despite having engaged in regular and unprotected intercourse for a year. The problem affects around one in seven couples in the U.K, which translates as approximately 3.5 million people.

For every 100 couples trying to get pregnant naturally, 84 will have achieved conception within one year, 92 within two years and 93 within three years. Some women conceive quickly, while others can take longer but generally, a visit to the GP is recommended if a woman has not achieved pregnancy after one year of trying. Women older than 36 or those with reason to believe they may have fertility issues may want to visit their GP sooner than this.

Infertility can be caused by various different problems and sometimes it is not possible to establish the cause. There may be a single cause in either partner or a combination of problems that may prevent conception occurring or a pregnancy continuing. Both men and women can have a problem with their fertility, which is the case in about 20% of infertile couples. In around 15% of cases, no cause of infertility is identified in either partner and this is referred to as “unexplained” infertility.

However, when causes are identified among women, they most commonly include irregular ovulation, endometriosis and obstructed fallopian tubes, while among men, the most common cause is sperm disorders.

Infertility is a common problem. In the U.S, 10 to 15% of couples are infertile. However, infertility is not the same as sterility, where there is no possibility of conception. Up to 15% of couples can be infertile, but only 1 to 2% of those are sterile and 50% of infertile couples who seek help, eventually conceive, either naturally or with medical assistance.

Below are estimates calculated from the National Survey of Family Growth, which used data collected from 2006 to 2010 to estimate infertility prevalence in the U.S.

• The number of women aged 15 to 44 years with an impaired ability to conceive or carry a baby to term (fecundity) is 6.7 million, which translates as 10.9%.
• The number of married women aged 15 to 44 years who are infertile is 1.5 million, or 6.0%.
• The number of women aged 15 to 55 years who have used infertility services at some point in their lives is 7.4 million.

An analysis conducted by the World Health Organization (WHO) which looked at 277 demographic health surveys in 190 countries, showed that the estimated levels and trends of infertility burden has remained similar between 1990 and 2010. For the study, infertility was defined as no live birth after five years of trying to get pregnant, which differs from the clinical definition of failure to conceive after one year. This definition was chosen so that infertility prevalence could be calculated from the hundreds of surveys, which included information on couple status, births, contraceptive use and fertility preferences.

The calculations showed that in 2010, 48.5 million couples globally were unable to have a child. Of women aged between 20 and 44 who wanted a child, 1.9% had not been able to have their first child after five years of trying and 10.5% of women who had previously given birth had not been able to have another baby after the same length of time. This represented decreases of just 0.1% and 0.4%, from 1990, respectively, which the researchers said shows little evidence of changes in fertility over the two decades.

One exception to this overall trend was observed in sub-Saharan Africa, where the rates of infertility dropped significantly. Lead author of the paper Gretchen Stevens, suggested that this may have been due to a decrease in rates of sexually transmitted diseases that can lead to infertility, as well as improvements in obstetric care.

Further Reading

• All Infertility Content
• Infertility – What is Infertility?
• What Causes Infertility?
• Infertility Treatments
• Infertility Ethics

Written by

Sally Robertson

Sally has a Bachelor's Degree in Biomedical Sciences (B.Sc.). She is a specialist in reviewing and summarising the latest findings across all areas of medicine covered in major, high-impact, world-leading international medical journals, international press conferences and bulletins from governmental agencies and regulatory bodies. At News-Medical, Sally generates daily news features, life science articles and interview coverage.