South Korea’s Health Ministry is revising its guidelines for in vitro fertilization, discouraging medical professionals from transferring more than three embryos in a single procedure to prevent possible adverse birth outcomes and unwanted multiple births.

Until now, the guidelines had stated that transferring as many as five embryos per IVF cycle was encouraged to maximize a patient’s chances of becoming pregnant.

However, both overseas and local studies have shown that transferring multiple embryos is associated with a higher risk for low birth weight and premature births.

“Preterm delivery and high risk pregnancies can become additional financial burdens to the patients,” said the Health Ministry in a statement explaining its reason for the revision. 

The number of Koreans who sought medical help for infertility has increased significantly in recent years, from 178,000 in 2007 to 215,000 last year.

With more Koreans opting to have children later in life, the number of pregnancies after age 35 is also increasing here, which is considered one of the biggest contributing factors to the rising number of preterm births in the country.

The number of premature births has increased dramatically since 2000, from 3.8 percent to 6.5 percent in 2013. In 2013, Korean babies born before 37 weeks of pregnancy and which died from premature birth complications accounted for 59.6 percent of the infant mortality rate in the country.

Also according to government statistics, 42.2 percent of all Korean mothers who became pregnant after undergoing IVF procedures gave birth to two or more children at a time, while only 2.2 percent of those who conceived naturally experienced the same.

The number of multiple births in Korea resulting from IVF procedures is significantly higher than in other countries, including the U.S. at 30.5 percent, Canada at 23.8 percent and Germany at 21.7 percent.

While Korea’s latest revision states that all medical experts should not transfer more than three embryos at a time, some overseas countries, such as Sweden and New Zealand, do not encourage the transfer of more than two embryos for a single IVF procedure.

A study by University of Bristol, which analyzed 124,148 IVF cycles, found that transferring three embryos in fact resulted in a lower birth rate than transferring two in younger women and made no difference in outcomes for older women.

In the U.S., 60 percent of IVF-related twin deliveries were preterm, compared to 11 percent of single deliveries from single-fetus pregnancies, according to the country’s Centers for Disease Control and Prevention.

By Claire Lee (dyc@heraldcorp.com)