Promising fertility treatment success rate for second baby

Women who used fertility treatment to conceive their first child have a good chance of having a second child the same way, according to a new study.

Researchers from the University of New South Wales in Sydney, Australia, have reported that women who have previously given birth following IVF have a 51 to 88 percent chance of having a second baby after six cycles of treatment. The study is the first to look at the chances of women having more than one IVF-conceived baby, which scientists hope will be helpful in counselling patients.

'We know that many women and couples want more than one baby to complete their family, and they want to be fully informed,' said senior author Professor Georgina Chambers. 'This data should reassure them that their chances of having a second baby through IVF is very good.'

The population-based cohort study, published in Human Reproduction, looked at 35,290 women who received IVF treatment using their own eggs and successfully gave birth between January 2009 and December 2013, in 90 clinics throughout Australia and New Zealand. The study followed the participating women another two years until December 2015, providing two to seven years of treatment follow-up. Among these mothers, 15,325 women (43 percent) with a median age of 36 years decided to repeat treatment in order to have a second child. From those trying for a second IVF child, 73 percent had frozen embryos available from their first IVF cycles.

The study includes estimations of two variations of cycle-independent cumulative birth rates (CLBR) for all patients. Both a conservative and an optimal CLBR were calculated, either assuming that dropped-out participants wouldn't have success in further treatment cycles (conservative) or that they would have the same chance of a live birth as those continuing the treatment in any cycle (optimal). The range between the two values gives patients an idea of where the realistic chances lie.

'Overall, 43 percent of women who recommence treatment with one of the frozen embryos from a previous stimulation cycle will have a baby after their first embryo transfer procedure. Between 61 percent and 88 percent of these women will have a baby after six cycles,' said Professor Chambers. 'Among those who recommence treatment with a new stimulation cycle and a fresh embryo transfer, 31 percent will have a baby after their first cycle and between 51 percent and 70 percent after six cycles.'

The study also revealed that success rates declined with women's age. However, in women aged 40 to 44, CLBRs after three cycles of treatment ranged between 38 to 55 percent when using a frozen embryo, and 20 to 25 percent when recommencing with fresh embryos from a new stimulation cycle. Reported factors positively affecting the chances for a successful second pregnancy included requiring only one cycle, a single embryo transfer for the first IVF-conceived baby, and infertility originating in factors affecting the male partner.

Co-author Dr Devora Lieberman said these results can help in counselling patients. 'However, it is important to note that these are population estimates and every couple is different,' she added. 'Our analysis does not take account of all individual factors that affect a woman’s chance of ART (assisted reproductive technology) success, including duration of infertility, and body mass index.'