An article recently claimed that reports of the age-related decline of women’s fertility overstated the case. The article attributes the message that women’s fertility declines with age to a backlash against feminism.

The Fertility Coalition’s Louise Johnson responds:

‘Everything you know about fertility is wrong’ isn’t right

Based on information in one article, Natalie Reilly in Daily Life (‘Everything you know about fertility is wrong’, June 26) asserts that the effect of ageing on women’s fertility has been overstated.

I am spokesperson for the Fertility Coalition, a group of four independent organisations concerned with reproductive health. The coalition launched the campaign Your Fertility last year to provide evidence-based information to men and women about the key factors that affect people’s ability to conceive and have healthy children.

We appreciate Ms Reilly’s concern that messages concerning age-related fertility decline can create anxiety for women. We also understand that the decision to have children is rarely simple and straightforward.

Unfortunately, for women the single biggest factor that will affect their ability to conceive and have a healthy baby is their age. Women are born with all the eggs they are going to have. Eggs decline both in number and quality over time. So that by the time a woman is 40, her fertility has halved.  As women age, there are also increased risks of miscarriage, pregnancy complications and birth defects.

If age-related infertility was a fiction, women in their late 30s and 40s would have equal chance of getting pregnant as younger women. A 2011 study by de Graaff and colleagues in ‘Fertility and Sterility’ shows that fertility declines with age, with the decline speeding up after age 35. The biological reasons for this are outlined in the article ‘Fertility and Ageing’ in the Oxford Journal’s ‘Human Reproduction Update’, published in 2005.