South Korea saw the first successful birth of quintuplets in 34 years, with help from dozens of doctors and nurses on the night of the delivery.

Seoul National University Hospital said Friday that the four girls and one boy were born there at around 10 p.m. Thursday. Twenty doctors and 10 nurses assisted in the cesarean section delivery.

The surgery was done under the lead of Dr. Jun Jong-kwan, a professor of obstetrics and gynecology at the hospital and an expert in multiple births. The children’s mother had been hospitalized since Saturday.

A cesarean section was done to avoid putting the mother at risk.

The pregnancy was the result of in vitro fertilization, which increases the chances of multiple births. The parents, both Army captains born in 1991, met in college and got married in December 2018.

The couple initially conceived six babies, but one died before birth. The hospital said the surviving quints were born without any serious health issues, but weighed less than average.

The widespread availability of in vitro fertilization has increased the number of twin births, but quintuplets are still a rarity, accounting for merely 0.0000024 percent of all births worldwide.

Before Thursday, the most recent quintuplet birth was in May in Dallas. Another quintuplet birth was reported in Poland early this year. In Korea, the last successful quintuplet birth was at SNU Hospital in 1987. That pregnancy too was the result of in vitro fertilization.