Had one baby through IVF? Your chances of a second are good

Women have a good chance of having a second child with the help of fertility treatment after their first was child born this way, according to a new study published in the journal Human Reproduction.

UNSW medical researchers looked at data from 35,290 women who received assisted reproductive technology (ART, also known as in vitro fertilisation or IVF) treatment between 2009 and 2013 in Australia and New Zealand and had a live baby during this time. These women were followed for a further two years to 2015, providing between two and seven years of follow-up data, and live births up to October 2016 were included.

Senior author Professor Georgina Chambers explained, “We explored two questions: what is a woman’s chance of achieving a second live birth in a particular cycle of treatment if previous cycles have failed, for instance in cycle three if the first two cycles have failed; and what is the overall, or cumulative, chance of a woman achieving a live birth after a particular number of cycles, including all the previous cycles. For example, what is the overall chance of a woman having a baby after up to three cycles?”

A cycle includes the stimulation of the ovaries to mature multiple eggs, the collection of eggs for fertilisation in the laboratory to create embryos, and then all embryo transfer procedures that use the embryos from the egg retrieval procedure. This can include fresh embryo transfers and frozen embryo transfers.

“We calculated estimates of cumulative live birth rates (CLBR) for women who were trying for a second ART baby that took account not only of the women who continued treatment, but also those who discontinued treatment,” Prof Chambers said.

“The conservative CLBR assumed that women who dropped out would have no chance of achieving a second live birth if they had continued treatment. The optimal CLBR assumed these women would have the same chance of a live birth in a particular cycle as women who had continued treatment.”

Just over 43% (15,325) of the 35,290 women, with an average age of 36, returned for treatment to conceive a second child by December 2015. Among these women, 73% used a frozen embryo from the egg retrieval cycle that had resulted in their first child, and for them the CLBR ranged from 61% (conservative estimate) to 88% (optimal estimate) after six cycles. Among the women who had a new stimulation cycle and used a fresh embryo, the CLBR ranged from 51% to 70%.

“Overall, 43% 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% and 88% of these women will have a baby after six cycles,” Prof Chambers said.

Although success rates declined with female age, the researchers found that after three cycles of treatment, the conservative and optimal CLBRs in women aged 40 to 44 years were 38% and 55% respectively in those that started with a frozen embryo and 20% and 25% in those recommencing with a new stimulated cycle and fresh embryos.

There are a couple of reasons for the differing success rates between women who started with fresh and frozen embryos.

“Frozen embryos remaining from a previous cycle originate from a biologically younger patient than those created in a new cycle,” said Dr Christos Venetis, a fertility clinician and clinical academic from the research team at UNSW.

“Frozen embryos also tend to indicate a better prognosis, since these women were able to produce multiple good quality embryos,” he said.

“Among those who recommence treatment with a new stimulation cycle and a fresh embryo transfer, 31% will have a baby after their first cycle and between 51% and 70% after six cycles.”

The study is said to be the first to explore the chances of achieving a second IVF baby after a first IVF child. Co-author Dr Devora Lieberman, a fertility clinician at City Fertility, said the results can be used to counsel patients.

“However, it is important to note that these are population estimates and every couple is different,” she said.

Image credit: ©stock.adobe.com/au/Dabarti

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