WEDNESDAY, Oct. 31, 2018 (HealthDay News) -- Women should wait a year or more between having babies, to reduce health risks to themselves and their infants, researchers report.
"Our study found increased risks to both mother and infant when pregnancies are closely spaced, including for women older than 35," said lead author Laura Schummers, a postdoctoral fellow in the department of family practice at the University of British Columbia (UBC).
"The findings for older women are particularly important, as older women tend to more closely space their pregnancies, and often do so intentionally," Schummers explained in a university news release.
The researchers analyzed data on more than 148,000 pregnancies in the Canadian province of British Columbia, and concluded that 12 to 18 months was the ideal length of time between giving birth and getting pregnant again.
Women over 35 who got pregnant six months after a previous birth had a 1.2 percent risk of serious complications or death. The risk was only 0.5 percent among those who waited 18 months before getting pregnant again.
Among these older women, the risk of preterm labor was about 6 percent among those who got pregnant within six months of giving birth. That risk dropped to 3.4 percent among those who waited 18 months before starting a new pregnancy.
With younger women, aged 20 to 34, the risk of preterm labor was 8.5 percent among those who got pregnant again within six months. That compared to 3.7 percent among those who waited 18 months before getting pregnant again.
The findings, published Oct. 29 in the journal JAMA Internal Medicine, provide guidance for older women who are planning families, said study senior author Dr. Wendy Norman. She is an associate professor in the department of family practice at UBC.
"Older mothers for the first time have excellent evidence to guide the spacing of their children," Norman said. "Achieving that optimal one-year interval should be doable for many women, and is clearly worthwhile to reduce complication risks."
The March of Dimes has more on pregnancy after age 35.