IVF, often blamed for rise in twin births, could reduce it

Although it is partly the cause for the rise in twin birth rate in recent years, in vitro fertilisation (IVF) could also be the most promising solution to reducing unintended twin births, argues an expert from Brown University.

The twin birth rate in the US has surged over the last 30 years, mostly because of reproductive technologies including in IVF.

Twins typically live healthy lives, but many of the serious medical complications of pregnancy and fetal development - such as preterm birth or low birth weight - are more common and difficult in twin pregnancies compared to in singleton ones, said Eli Adashi in a new editorial in the American Journal of Obstetrics & Gynecology.

For that reason, many physicians and public health officials consider technology's artificial contribution to the soaring twin birth rate to be problematic.

Meanwhile, many people who employ reproductive technologies are not necessarily trying to have twins - the technologies simply carry a greater risk of producing them.

"Sometimes nature makes it happen and there is not a whole lot you can, or want to, do about it," Adashi, professor of obstetrics and gynecology, noted.

"But in cases of IVF or other technologies, if you can avoid it, you often want to," Adashi noted.

In IVF, doctors often intentionally fertilise more than one egg in the lab and then implant those multiple embryos in a woman's womb, in hopes that at least one will develop successfully.

In recent years, doctors have cut the number of implantations down to two in most cases, reducing the incidence of triplets and quadruplets, but increasing the rate of twin births.

The high cost of IVF is part of the reason people often implant multiple embryos, Adashi said.

If a single parent or couple can only afford to do the procedure once or twice, they want the best chance of success each time. For those who want children, it is preferable to have twins than no kids.

If cost were not a problem for would-be parents, the ideal case would be to implant just one embryo, Adashi explained.