Mothers should wait a minimum of one year before getting pregnant again after they give birth, according to a new study.
The research, carried out by the University of British Columbia and the Harvard T.H. Chan School of Public Health and published in JAMA Internal Medicine, found that a pregnancy gap of less than one year was associated with risks for women of all age.
Waiting one year before getting pregnant again
Getting pregnant again within one year of birth was found to carry higher risks for women aged over 35. Risks to the infant were found for all women but were greatest for mothers aged between 20 and 34.
“Our study found increased risks to both mother and infant when pregnancies are closely spaced, including for women older than 35,” said Laura Schummers, the study’s lead author, “The findings for older women are particularly important, as older women tend to more closely space their pregnancies and often do so intentionally.”
The study is the first to investigate pregnancy spacing and maternal mortality or severe morbidity (rare but life-threatening complications of pregnancy or birth) in a high income country.
The researchers examined data from 148,544 pregnancies in British Columbia. This date was taken from birth records, hospitalisation data, infertility data and census records.
Among women aged over 35 who fell pregnant six months after a previous birth, there was a 1.2 per cent risk of maternal mortality or severe morbidity. An 18 month gap, however, reduced this risk to 0.5 per cent. With a six-month gap between pregnancies, the risk of spontaneous premature birth was found to be six per cent. This dropped to 3.4 per cent for older mothers who waited 18 months before falling pregnant again.
In younger women, researchers found an 8.5 per cent risk of spontaneous premature birth for women with a six-month gap between pregnancies. This dropped to 3.7 per cent for women who waited 18 months between pregnancies.
“Short pregnancy spacing might reflect unplanned pregnancies, particularly among young women,” said Dr. Sonia Hernandez-Diaz, professor of epidemiology at the Harvard T.H. Chan School of Public Health. “Whether the elevated risks are due to our bodies not having time to recover if we conceive soon after delivering or to factors associated with unplanned pregnancies, like inadequate prenatal care, the recommendation might be the same: improve access to postpartum contraception or abstain from unprotected sexual intercourse with a male partner following a birth.”
Current World Health Organisation advice is to wait 18 months between pregnancies. However, the authors of this new study feel that one year is enough to noticeably reduce the risks of shorter spacings.
”Older mothers for the first time have excellent evidence to guide the spacing of their children,” said study author Dr. Wendy Norman, “Achieving that optimal one-year interval should be doable for many women and is clearly worthwhile to reduce complication risks.”
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