• Babies born to women aged 40 and over from assisted reproduction have fewer birth defects compared with those from women who conceive naturally at the same age. (Science Photo Library RF/Getty Images)Source: Science Photo Library RF/Getty Images
New Australian research shows that babies born to women aged 40 and over from assisted reproduction have fewer birth defects compared with those from women who conceive naturally at the same age.
By
Yasmin Noone

Source:
University of Adelaide
18 Oct 2016 - 4:18 PM  UPDATED 18 Oct 2016 - 4:28 PM

Older women who want to become mothers could benefit from accessing assisted reproduction services to have a baby, with new research out this week showing that IVF could be the healthier option for the child if mum is aged 40-plus. 

According to a study from the University of Adelaide, babies born to women aged 40 and over from assisted reproduction have fewer birth defects compared with those from women who conceive naturally at the same age.

In births from assisted reproduction, the prevalence of birth defects ranged from 11.3 per cent at its highest for women less than age 30 using ICSI (intracytoplasmic sperm injection), down to 3.6 per cent for women aged 40 and older using IVF.

For natural conceptions, the corresponding prevalence across age groups was 5.6 per cent in young women, increasing to 8.2 per cent in women aged 40-plus. 

“They show that infertile women aged 40 and over who used assisted reproduction had less than half the rate of birth defects of fertile women of the same age, while younger women appear to be at an elevated risk.”

The research finding is contrary to widespread belief that the greater risk of birth defects after assisted conception is due to the frequent use of these services by older women.

"There's something quite remarkable occurring with women over the age of 40 who use assisted reproduction," says lead author Professor Michael Davies from the University of Adelaide's Robinson Research Institute.

"We know from our previous studies that women who undergo assisted reproduction have an increased rate of birth defects compared to women who conceive naturally.

“We also know that among women who conceive naturally, the rate of birth defects increases exponentially from age 35 onwards. Therefore, it was widely assumed, but untested, that maternal age would be a key factor in birth defects from assisted reproduction. However, our findings challenge that assertion.

“They show that infertile women aged 40 and over who used assisted reproduction had less than half the rate of birth defects of fertile women of the same age, while younger women appear to be at an elevated risk.”

The study finds that women treated with IVF and ICSI combined faced the greatest age-related risk of birth defects when aged around 29 years of age.

“With a prevalence of 9.4 per cent, their risk was more than double the rate of 3.6 per cent observed for the patients aged over 40, and significantly higher than for fertile women of the same age, at 5.6 per cent," Professor Davies says.

The average prevalence of a birth defect was 5.7 per cent among naturally conceived births, 7.1 per cent for the IVF births, and 9.9 per cent for the ICSI births, across all age groups.

The research, published in BJOG: An International Journal of Obstetrics & Gynaecology (BJOG) was based on data of all live births recorded in South Australia from 1986-2002 – more than 301,000 naturally conceived births, as well as 2200 births from IVF and almost 1400 from ICSI.

The average prevalence of a birth defect was 5.7 per cent among naturally conceived births, 7.1 per cent for the IVF births, and 9.9 per cent for the ICSI births, across all age groups.

According to a report from the Australian & New Zealand Assisted Reproduction Database (ANZARD), there were 67,707 assisted reproduction treatment cycles reported from Australian clinics in 2014. This represented a 2.4 per cent increase in Australia.

The average age of women undergoing autologous cycles was 35.8 years in 2014, similar to previous years. The average age of women undergoing treatment using donor oocytes or embryos was approximately five years older at 40.4 years.

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Professor Davies says these results could have broader implications for infertility treatment, if researchers can understand why older women do better on assisted reproduction.

"There is some aspect of IVF treatment in particular that could be helping older women to redress the maternal age issues we see among natural conception, where we observe a transition at around the age of 35 years toward a steadily increasing risk of birth defects.

“We don't know what that is quite yet – it could be an aspect of hormonal stimulation that helps to reverse the age-related decline in control of ovulation.

"More research is desperately needed in this area to understand why this is occurring, and whether it could be adapted to both fertile and infertile women in future to prevent birth defects, which continue to be a major cause of death and disability in the first year of life globally."

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