File photo: Actress Nicole Kidman was 43 when her second daughter was born via a surrogate mother. Picture: AP

London - Celebrities are misleading women that getting pregnant over 40 is easy by not revealing they have used IVF or had fertility problems, researchers say.

Interviews and reports of older stars giving birth create the impression that "age is just a number".

Experts warned that a failure to be open about fertility was leading to "devastating consequences".

They said women are being misled into thinking pregnancy is more straightforward past the age of 35 than it is, in reports that "glamorise" being an older mother – without mentioning the difficulties or the risks, such as stillbirth, miscarriage and abnormalities.

Having a baby at "advanced maternal age" gets much harder as fertility levels plummet in a woman’s mid-to-late 30s and early 40s – but this is not always made clear, the US researchers said. Reports of women having twins late into their 40s or even 50s, without any mention of the use of IVF, also create a false impression.

The authors suggested that the stigma attached to infertility may be the reason why it is not mentioned.

But they said "reproductive-aged women frequently overestimate the likelihood of fertility at advanced reproductive ages resulting in the devastating consequence of unintended childlessness".

The scientists’ report, to be presented this week to the American Society for Reproductive Medicine (ASRM) in San Antonio, Texas, does not list older stars who have given birth without their fertility problems being reported. However, a handful have been forthright about their struggles with having children. 

They include actress Nicole Kidman, who was 43 when her second daughter was born via a surrogate mother; the model Caprice, who also used a surrogate in her early 40s; and singer Mariah Carey, who was 41 when she had twins through IVF.