There’s a better way to practice in vitro fertilization – one that leads to fewer multiple births and reduces danger to mothers and their children.
It has been more than 30 years since the world welcomed Louise Brown, the first successful test-tube baby. Since then, the range of available reproductive technologies has expanded rapidly.
Beyond in vitro fertilization (IVF) – where egg and sperm are joined outside the body to make an embryo – there is egg and embryo freezing, egg, sperm, and embryo donation, contract pregnancy, intracytoplasmic sperm injection (widely known by the acronym ICSI), and in vitro maturation of eggs, to name a few.
With so many reproductive options, questions arise about how much control patients should have over the use of reproductive technologies, and whether patients and providers are paying enough attention to the interests of children born using these technologies.
In North America, this debate has been spurred on by two recent cases.
First, there was the well-documented story of Nadya Suleman (christened by the media as Octo-Mom), an American woman who gave birth to octuplets in January 2009. Ms. Suleman, an unemployed single mother on public assistance with six children already (all of whom were conceived through IVF), insisted that her fertility doctor transfer her remaining six frozen embryos in one cycle (two of the embryos divided to create twins).
The second highly controversial case occurred in Canada in February 2009, when Mrs. Hayer – a 60-year-old woman with a 60-year-old-husband – gave birth to premature twins in a Calgary hospital. This Canadian couple had travelled to India for fertility treatment denied to them by Canadian physicians. Using IVF and donor eggs from a much younger woman, Ranjit Hayer became pregnant with triplets. One of the fetuses was “selected” for termination.
Leaving aside the many differences between these two situations, what they have in common is multiple pregnancy as a complication of infertility treatment. In both cases, more than one fertilized egg was placed in the woman in the hope of achieving a pregnancy.
To put this “complication” in perspective, the natural occurrence of twins following spontaneous conception is 1per cent. In North America and Europe, twin births following assisted human reproduction are between 20 and 30 per cent.
Multiple pregnancy is potentially harmful for pregnant women and for their offspring. The pregnant woman is at increased risk of preeclampsia and miscarriage, while the fetuses are at increased risk of premature birth and long-term disabilities.
One option for avoiding multiple pregnancy is selective reduction, which is what the Hayers elected to do. Another, arguably less ethically controversial, option is single-embryo transfer.
Recent evidence suggests that fresh single-embryo transfer followed by frozen-and-thawed single-embryo transfer (if needed) is just as effective in achieving a pregnancy as fresh double-embryo transfer, and it substantially reduces the probability of multiples. In turn, reducing the multiple birth rate contributes to improved outcomes for children born of assisted human reproduction.
These facts need to be carefully considered by patients, clinicians, relevant professional organizations, and policy makers. In Canada, the Joint SOGC-CFAS Guidelines for the Number of Embryos to Transfer Following In Vitro Fertilization advises physicians to transfer one or two embryos to women under 35 (with the higher number reserved for cases with an unfavourable prognosis), two or three embryos to women 35 to 39, and three or four embryos to women aged 40 or older.
There is no policy that favours single-embryo transfer over multiple-embryo transfer for all or most IVF patients. Meanwhile, in other jurisdictions (most notably the United Kingdom) there are national strategies to promote single-embryo transfer and reduce the number of multiple births following assisted human reproduction.
The challenge before us is to shift well-entrenched practices that make multiple pregnancy so common among users of assisted human reproduction. We – clinicians, relevant professional organizations, policy makers, and the general public – need to champion single-embryo transfer for the benefit of us all, but most particularly for the benefit of the children born of assisted human reproduction.
*Françoise Baylis is a member of the Board of Directors of Assisted Human Reproduction Canada. The views expressed herein are her own.*
