Babies conceived using fertility treatments, including IVF are at no more risk of birth defects than naturally conceived infants, a large US study shows. Researchers at Stamford Hospital in Connecticut looked at data from over 36,000 pregnancies, around five per cent of which arose following fertility treatments. But their findings, published in the journal Obstetrics and Gynecology, did show that pregnancies following assisted conception are at higher risk of complications such as high blood pressure, diabetes and placental problems.
Previous studies have also shown that overall, children conceived by IVF are no more likely to have major health problems than naturally conceived children. There is no evidence to suggest that IVF increases the incidence of major birth defects, cancers or problems in psychological or emotional development. However, some studies have linked IVF to a slightly increased risk of some rare genetic conditions caused by faulty 'genetic imprinting', such as Beckwith Wiedemann syndrome.
In the latest study, the researchers studied the outcomes of 36,062 pregnancies - 1,222 of which involved fertility treatments such as ovulation induction, and a further 554 involving IVF treatment. They found no evidence of an increased risk of low birth weight, birth defects or chromosomal abnormalities in the babies born following assisted conception. 'This is good news', said lead author Tracy Shevell, adding 'the chances of conceiving and having a healthy baby using assisted reproductive technology overall are very high'.
However, the women who had conceived using IVF were six times more likely to develop placenta previa, in which the placenta either partially or completely covers the cervix. They were also 2.7 times more likely to develop pre-eclampsia, a potentially serious complication of pregnancy, and 2.3 times more likely to need caesarean deliveries. Women who had either IVF or ovulation induction were 2.4 times more likely to be affected by placental abruption, a condition in which the placenta comes away from the uterine wall.
It is not known why fertility treatments should be linked to an increased risk of pregnancy complications, but one explanation could be the underlying causes of some forms of infertility. 'It should not be surprising that women who had a medical problem that made it difficult for them to get pregnant also had problems once they became pregnant', said William Gibbons, president of the Society for Assisted Reproductive Technology. He added that the other complicating factor could be age. 'Women who undergo infertility treatments are often older than most women who become pregnant. Age in and of itself is a risk factor for a more complicated pregnancy', he said.