For women undergoing in vitro fertilization, implanting a single embryo not only results in lower health costs compared to implanting two or more, it appears to be more successful at achieving a healthy birth, concludes a new study.
The findings come from a long-running study in Finland. The authors say the findings should counter fears that relying on just one embryo reduces a woman's chances of having a baby.
The Finnish researchers compared the outcomes of 1,510 women under the age of 40 who sought fertility treatment at the infertility clinic at Oulu University Hospital.
They looked at two time periods: between 1995 and 1999, when transferring two embryos to the womb was more common, and between 2000 and 2004, when single embryo transfers had become the more common approach.
The researchers found that more full-term babies were born for women who received a single embryo. Those who had just one embryo transferred to their wombs had birth rates of nearly 42 per cent, compared to about 37 per cent for those who received multiple embryos.
Single embryo transfers also halved the rates of multiple pregnancies, which can lead to medical complications or death for both babies and mothers.
What's more, the researchers found that multiple embryo transfers were more expensive in the end - particularly because of the costs related to treating complications caused by multiple births.
The team found that the total treatment cost in the women who chose single embryo transfers was, on average, five per cent less per woman than for women in the double embryo transfer period. The costs ranged from two to 20 per cent less.
The results should help assure parents considering in vitro fertilization that choosing to transfer just one embryo will provide the best outcome, says Dr Hannu Martikainen, Chief Physician of the Division of Infertility and Reproductive Endocrinology at the University of Oulu.
"Our study, thus, reflects sSET [elective single embryo transfer] in everyday practice with an outcome measure consistent with what patients actually want: a live healthy baby achieved in a cost-effective way," his team writes in the journal Human Reproduction.
In vitro fertilization involves surgically removing eggs from a woman's ovaries and combining them with sperm in the lab. Doctors then pick the best of the resulting embryos and implant them in the uterus.
The debate about how many embryos to implant has raged since 1978, when the world's first "test-tube baby", Louise Brown, was born.
The debate intensified earlier this year when Nadya Suleman reported she had six embryos transferred in her most recent IVF cycle and gave birth to eight newborns, nine weeks premature.
It took a team of 52 health professionals to deliver the brood, including three obstetricians, seven neonatologists and 24 nurses. The medical costs of the octuplets have not been disclosed, but it's estimated to be over US $1 million.
Many parents considering IVF have had to decide between transferring more than one embryo and risking a multiple pregnancy versus the cost of paying for another cycle if the first single embryo cycle failed. IVF cycles typically cost about $12,000 in Canada.
"At a time when there is an intense debate in many countries about how to reduce multiple pregnancy rates and provide affordable fertility treatment, policy makers should be made aware of our results," write Martikainen.
"These data should also encourage clinics to evaluate their embryo transfer policy and adopt eSET as their everyday practice for women younger than 40."
