One in five women become pregnant naturally after having a baby conceived with IVF

One in five women become pregnant naturally after having a baby through IVF, scientists have found, suggesting fertility techniques may actually boost natural conception.

Experts at University College London said women should be made aware that the chance of naturally conceiving was relatively high following fertility treatment.

A study of more than 5,000 women found that a significant number (around 20 per cent) who struggled to conceive became pregnant without help, following fertility treatment.

Although scientists do not know what is driving the effect, they speculated that ovarian stimulation from IVF cycles may improve general function of the ovaries.

Hormonal changes that occur during pregnancy may also help women conceive naturally, while women may simply be less stressed after successfully giving birth. Stress is a known factor which drives infertility.

Lead author, Dr Annette Thwaites, said: “Our findings suggest that natural pregnancy after having a baby by IVF is far from rare.

“This is in contrast with widely held views – by women and health professionals – and those commonly expressed in the media, that it is an unlikely event.”

Dr Thwaites said reduced stress may be a factor.

“The importance of psychological factors on fertility is well-recognised. There are lots of theories on this. It’s biologically possible that ovarian stimulation from IVF cycles may improve ovarian function.

The team say the findings are important, because many women may not realise that they could conceive naturally following fertility treatment.

Becoming pregnant again quickly

This could lead to them becoming pregnant again quickly or when they are not ready.

Shema Tariq, 47, a doctor and academic from London, was diagnosed with low ovarian reserve and told that her chances of conceiving without IVF were almost zero.

It took six rounds of IVF before she gave birth to her son in 2019, yet she conceived naturally within eight months of the birth.

“My GP briefly mentioned contraception to me after he was born, but we both laughed and agreed that it wasn’t relevant.

“It never occurred to me that I might get pregnant (despite being a sexual health doctor).  I was 43 and had been told that my chances of conceiving naturally were less than one per cent.

“Eight months later I was unexpectedly, and naturally, pregnant with our daughter. She has been the most wonderful surprise, but when we first found out I felt overwhelmed and unprepared for another pregnancy.

“If I’d known that one-in-five women conceive naturally after IVF I’d have used contraception until I was ready both emotionally and physically.”

IVF was first used in 1978 and now, more than 10 million babies worldwide have been born using the treatment – equating to between one per cent and six per cent of all babies born per year in the developed world by 2020.

More than 50,000 patients each year undergo IVF treatment in Britain.

The finding that a substantial number of women can conceive naturally after fertility treatment may also help couples avoid spending needless money on treatment.

Dr Thwaites added: “Knowing what is possible would empower women to plan their families and make informed choices regarding further fertility treatment and/or contraception.”

The research was published in the journal Human Reproduction.