Women who wait between 18 and 23 months before conceiving again after giving birth are most likely to have a healthy baby.
Researchers have identified this five month period as the most optimum to conceive anything before or after and the chances of a healthy baby decrease, irrespective of the age of the mother.
Babies who were conceived less than six months after a birth were 1.4 times more likely than those conceived during the optimum period to have a low birth weight, 1.4 times more likely to be a preterm birth, and 1.3 times more likely to be undersized.
The risks increase for those mothers who wait longer than the optimum period to conceive, researchers from the Centers for Disease Control and Prevention in Atlanta discovered. Women who wait 10 years after giving birth to conceive again doubled the risk of having a baby with a low birth weight.
The CDC researchers based their study on 173,205 births recorded in Utah between 1989 and 1996 (N Engl J Med, 1999; 340: 589-94).