Japan sees record multiple pregnancies after fertility insurance expansion

The figure was up 36 percent from 2022, with researchers saying the rise may reflect an increase in patients choosing to transfer multiple embryos in the expectation of completing treatment within the limited number of cycles covered by insurance.

Multiple pregnancies, such as twins and triplets, carry higher risks for pregnant women. The Japan Society of Obstetrics and Gynecology recommends in principle that only one embryo be transferred at a time.

Japan's public insurance system covers embryo transfers up to six times for women who were under 40 when they started fertility treatment and up to three times for those aged 40 to 42.

"The insurance system needs to be reviewed, taking into account the potential burden of high-risk pregnancies on perinatal care," said Ayumu Ito, a lecturer at Toho University, which was involved in the study.

During in vitro fertilization, multiple embryos may be transferred at one time to increase the chance of pregnancy, raising the likelihood of multiple pregnancies. The rate of such pregnancies surpassed 10 percent through 2007.

In 2008, the society recommended single embryo transfer in principle. It said two embryos may be transferred for women aged 35 or older and those who had failed to become pregnant after two or more transfers.

The multiple pregnancy rate subsequently dropped, remaining at around 3 percent from 2014 onward. It rose to 3.8 percent in 2023, the year after public insurance coverage was expanded to fertility treatment, according to the study's analysis of the society's database.

Most of the cases involved twins, while there were 69 cases of triplets and six cases of quadruplets, according to the study.

The total number of assisted reproductive technology procedures also rose. Furthermore, the researchers found that transfers of two or more embryos surged particularly among people aged 41 or older.

Earlier, Japanese scientists created a rapid test for the tick-borne SFTS virus.