IVF does not increase a woman’s risk of breast, ovarian or womb cancer, research suggests today.
Previous studies imply fertility treatment raises women’s risk of such diseases due to the high levels of hormones they are exposed to.
Yet scientists from University College London discovered women are only more likely to develop such conditions after IVF if they have other risk factors for them, such as a family history of cancer.
Since the first ‘test-tube baby’ was born in July 1978, up to five million infants have been born by IVF worldwide.
In the UK and US, around one in eight women will develop breast cancer at some point in their lives. Womb cancer is the fourth most common form of the disease.
The researchers analysed 255,786 women who had IVF in the UK between 1991 and 2010.
The women, who were followed for around eight years, were on average 34 years old and had completed one round of IVF at the start of the study.
Of the women, 19 per cent had an unclear cause of infertility.
In 44 per cent of cases the cause was thought to relate to the women, while male problems accounted for 33 per cent of cases.
Results suggest IVF slightly increases women’s risk of developing breast cancer that affects the milk ducts but not that which invades normal breast tissue.
Women with other risk factors for ovarian cancer, such as being overweight or smoking, put themselves at risk of the condition if they have IVF, however, this risk does not apply to most.
IVF does not increase any women’s likelihood of womb cancer, the study adds.
The findings were published in the journal BMJ.
This comes after research released last March suggested infertile women are over 50 per cent more likely to become pregnant if they are treated with two key hormones.
Among infertile women undergoing IVF after two unsuccessful attempts, 54.3 per cent become pregnant and 51.4 per cent go on to have a live birth after receiving the growth hormones estradiol and progesterone, a study by the University of Granada found.
This is compared to just 17.1 per cent of infertile women who try IVF for a third time without these hormones, the research adds.
Estradiol and progesterone are thought to improve blood flow to the lining of the uterus, preparing it for egg implantation.
Researchers plan to investigate whether women suitable for such treatment can be identified before having to endure repeated IVF failures.