One in five women conceive naturally after having IVF baby

The likelihood of becoming pregnant naturally after having a baby via IVF could be around 20 percent, a review has found. 

The findings contradict common assumptions about natural pregnancy rates after fertility treatment, and show in fact they are 'far from rare', at approximately one in five.

'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,' said lead author of the study, Dr Annette Thwaites, from University College London's Elizabeth Garrett Anderson Institute for Women's Health.

Dr Thwaites and her team examined 11 studies held globally during the 41 years between 1980 and 2021, which included data for over 5000 women. The rate of women having a natural conception or live birth after IVF or ICSI ranged from 12 to 33 percent, occurred mostly within three years and tended to be higher in more recent cohorts.

Indeed, one study from 2013 found no significant difference between women getting pregnant naturally after IVF and those who conceived their first child without fertility treatment.

The researchers suggest that 'it is biologically plausible that ovarian stimulation from IVF cycles may improve ovarian function' and that reduced stress and the regression of certain endocrinological conditions like endometriosis could also play a role in the results.

They also suggested that an observed increase over time in the number of pregnancies observed after IVF births, could be due to IVF being offered for an increasing number of conditions. There was a risk of confirmation bias also, as women who conceived naturally after IVF were more likely to report the experience. Data had not been collected on breastfeeding duration or contraception use. 

As part of the research, the team interviewed women who had conceived naturally after fertility treatment. Dr Shema Tariq, a doctor and academic from London, 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. 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 percent. 

'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.'

Dr 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 was published in the journal Human Reproduction.