Seven-month-old conjoined twins from Zimbabwe were in critical condition and on life support on Tuesday after being separated the day before by doctors in Toronto.

Their condition, which is not expected to change quickly, is normal after this type of surgery, a spokeswoman for the Hospital for Sick Children in Toronto said.

Tinashe and Tinotenda, who were born joined at the abdomen and whose livers were connected, underwent four- and five-hour surgeries, respectively, on Monday in an operation that involved a 25-member surgical team.

“The separation surgery went as planned with no unexpected complications,” said Dr. Jack Langer, chief of general surgery at Toronto Sick Kids.

Langer said that while doctors were optimistic, the boys would have to be monitored for infection or bleeding.

Doctors said in December that without surgery, chances of long-term survival were slim for the twins. Tinotenda, the smaller of the two, had already been showing signs of becoming a “donor” twin, with more of his blood flowing into his brother Tinashe’s liver through a joint artery.

The boys, who were delivered by Canadian doctors working in a rural area of Zimbabwe, arrived in Toronto on Dec. 2 accompanied by their 40-year-old mother and a nurse.

After they recover from the operation, the twins will both eventually undergo surgery to correct cleft lips and palates before returning to Zimbabwe.

Conjoined twins occur roughly once in every 50,000 births and few are born alive or live long.