Japan Has Record Number of Twin and Triplet Births After Insurance Change

Japan saw a record number of multiple pregnancies in 2023, with 4,354 cases of twins, triplets, and quadruplets. This happened after the country's health insurance began covering fertility treatments in 2022. The number of multiple births went up 36% from the year before. Scientists think this increase happened because more people chose to transfer multiple embryos at once to improve their chances of getting pregnant within the limited insurance coverage.

Multiple pregnancies can be dangerous for mothers and babies. The Japan Society of Obstetrics and Gynecology says doctors should only transfer one embryo at a time. This is the safest way to help women get pregnant through fertility treatments. However, some patients ask for multiple embryos to increase their chances of success.

Japan's public insurance covers fertility treatments differently based on age. Women under 40 can get up to six embryo transfers covered by insurance. Women aged 40 to 42 can get up to three transfers covered. After insurance started covering these treatments, more people began using them.

During fertility treatments, doctors can put multiple embryos into a woman's body at the same time. This makes it more likely she will get pregnant, but it also makes twins or triplets more likely. Before 2008, more than 10% of these pregnancies resulted in multiple babies. The medical society then recommended using only one embryo at a time.

After doctors started following this rule, multiple pregnancy rates dropped to about 3% and stayed there from 2014 onwards. But in 2023, the rate went up to 3.8% after insurance coverage expanded. Most of these cases were twins, but there were also 69 cases of triplets and six cases of quadruplets.

Ayumu Ito, a teacher at Toho University who worked on the study, thinks the insurance system should be changed. The insurance system needs to be reviewed taking into account the potential burden of high-risk pregnancies on perinatal care. He worries that too many high-risk pregnancies could put strain on hospitals and medical care for mothers and babies.