Women with certain health problems are more likely to deliver prematurely.
They followed 2,422 women who, for various reasons, were considered to be at high risk of delivering prematurely.
The baby was delivered prematurely, possibly as a result of the surgery, but seemed to be doing well.
Also, women who do not have access to health care are less likely to visit a doctor, therefore increasing their risk of delivering prematurely.
In each group about 14 percent of the women delivered prematurely, at less than 35 weeks' gestation.
The couple's son, delivered prematurely by Caesarean section that night, died 17 days later.
Researchers have made inroads into understanding why women deliver prematurely.
The researchers found that girls aged 13 to 17 were nearly twice as likely to deliver prematurely than older mothers in the group.
He prescribed narcotics to pregnant patients, one of whom prematurely delivered a baby who soon died.
Susan survives the difficult childbirth and so does her prematurely delivered son.