Increased pre-eclampsia risk linked to IVF pregnancies doctors warn
IVF increases the chance of a potentially fatal pregnancy condition by 41pc, research suggests.
Data from six studies found the risk of pre-eclampsia was much higher in IVF pregnancies than among those conceived naturally.
Pre-eclampsia usually occurs from around 20 weeks of pregnancy and can lead to women suffering high blood pressure, protein in the urine and fluid retention.
Experts do not know exactly what causes the condition to develop but it causes issues with the placenta and can lead to growth problems in the baby.
Mild pre-eclampsia can be closely monitored but, in more severe cases, women must be admitted to hospital and may need to be delivered prematurely.
Women can also go on to develop eclampsia, a type of seizure which can be life-threatening for mother and baby.
Around six women and several hundred babies die every year in the UK from complications caused by pre-eclampsia.
In the latest study, experts from US universities and research centres, including the National Institutes of Health, pooled data from six studies.
These included pregnancies from standard IVF and IVF using donor eggs. Control groups included women who conceived naturally and those who had artificial insemination.
In the IVF groups, the risk of pre-eclampsia was 41pc higher than in the control groups, the findings showed.
The researchers, who are presenting their findings at the American Society for Reproductive Medicine (ASRM) conference in Orlando, suggest that exposing embryos to in vitro culture could produce subtle changes which lead to poor development of the placenta and its blood supply.
This in turn increases the risk of pre-eclampsia.
The researchers controlled for other factors likely to influence the results, such as the women's age.
Charles Kingsland, a consultant gynaecologist at the Liverpool Women's Hospital and member of the British Fertility Society, said the findings were interesting, adding: "We are aware as obstetricians that IVF pregnancies bring with them their own risks."
He said the research suggested that the problem lay in how the placenta developed following IVF.
NHS figures suggest mild pre-eclampsia can affect up to 10pc of first-time pregnancies and is severe in 1pc to 2pc of pregnancies.