About one in five women become pregnant naturally after having a baby using fertility treatment such as IVF, according to research.
Scientists at University College London said women should be aware that natural pregnancies after IVF were not as unusual as thought.
The experts said a study of more than 5,000 women showed that 20% of those who sought assisted conception for their first child were able to become pregnant naturally within three years.
Dr Annette Thwaites, the lead author from UCL’s EGA Institute for Women’s Health, 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 a highly unlikely event.”
The researchers analysed data from 11 studies of more than 5,000 women around the world between 1980 and 2021, including 1,160 from the UK.
They speculated that fertility techniques could boost natural conception, saying: “It is biologically plausible that ovarian stimulation from IVF cycles may improve ovarian function.”
They also suggested that hormonal changes that occur during pregnancy and reduced stress after giving birth may also help women conceive naturally.
The team said a vast majority of participants in the studies had subfertility, in which conceiving takes longer than typically expected. It means not all women seeking and undergoing fertility treatment are absolutely or permanently infertile, they added.
A small number of participants underwent the IVF procedure due to reasons not related to infertility, such as being in a same-sex relationship, being a single parent or being a surrogate.
With more than 10 million babies born worldwide via IVF, the researchers said it was important for those who have had successful treatment to know how likely they were to conceive naturally afterwards.
Thwaites said: “Knowing what is possible would empower women to plan their families and make informed choices regarding further fertility treatment and/or contraception.”
The research, published in the journal Human Reproduction, also included a report featuring interviews with 22 women in the UK who experienced natural pregnancy after fertility treatment.
Shema Tariq, a doctor and academic from London who has two children aged three and four, was diagnosed with low ovarian reserve and told that her chances of conceiving without IVF were almost zero.
The 43-year-old said: “It took six rounds of IVF to conceive our son, who was born in 2018. My GP briefly mentioned contraception to me after he was born, but we both laughed and agreed that it wasn’t relevant.
“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.”
According to the NHS, about one in seven couples may have difficulties getting pregnant. More than 50,000 patients undergo IVF treatment in Britain each year.
