Waiting a year between pregnancies reduces health risks, study finds

By Naomi Thomas, CNN

According to a new study, women and their babies face health risks less than 12 months elapsed between the birth of a child and the conception of the next child.

The researchers found a modest increase in the risk of death or serious illness in the mother at intervals of less than 12 months and a greater increase in the risk of adverse effects to the baby before and after birth, as well as Spontaneous premature delivery.

The World Health Organization guidelines suggest that women wait at least two years before becoming pregnant again. The American College of Obstetricians and Gynecologists suggests that women avoid periods of pregnancy less than six months and "should be informed of the risks and benefits of a new pregnancy more early than 18 months ".

The authors noted that the study found an optimal interval between pregnancies shorter than expected by all women. "The results can be reassuring, especially for older women who have to weigh the competing risks of increasing maternal age" with the risk of time between pregnancies, they wrote.

The study, published Monday in the journal JAMA Internal Medicine, looked at 123,122 women and 148,544 pregnancies and focused on the application of health risks to pregnant women of different ages. Participants were found in population health databases in Canada, which included all women who had at least two consecutive single pregnancies over a 10-year period.

For the 35 years and over, the risk of maternal mortality and serious morbidity was 0.62% while there were only six months between the birth of a child and the conception of the next and 0.26% to 18 month. For mothers aged 20 to 34, the predicted risk was 0.23% at six months and 0.25% at 18 months.

However, younger mothers had a higher risk of spontaneous premature labor with shorter pregnancy interruptions – 5.3% at six months and 3.2% at 18 months – and results. unfavorable for the fetus and the infant – a predicted risk of 2.0% at six months, compared to 1.4% at 18 months. months – than older women.

This breakdown is relevant because the age at which American women have their first child is increasing, due to changes in society and workplaces, according to the authors of an editorial published in parallel to the study.

"This is a fairly common question now, because for people like me who see a lot of patients who are 40 years old and have their first baby, the first question usually if we are unscathed is this: "When can I have my neighbor? ? "Said Dr. Laura Riley, Chair of Obstetrics and Gynecology at Weill Cornell Medicine and New York-Presbyterian, who did not participate in the research.

She said that one of the strengths of the study was that she looked at the age of women versus the risks, as well as the size of the study population.

"What I mainly remember is that this association between a short interval of pregnancy and a poor pregnancy outcome is well known, but it shows that it is for all ages of the mother," she said. she said. "It does not matter if you're 20 or you're 40 years old."

The authors of the study also attempted to explain other factors that could lead to an adverse outcome of pregnancy, including whether the pregnancy was considered and whether the mother lived in a rural area.

The research examines possible health issues for the mother and baby, for which the previous data focused more on fetal health, according to Riley.

"They had maternal mortality and severe morbidity, which is another important piece of information because people often focus on the baby and forget that there are also untoward results for the mother," she said.

Even though the risk of short pregnancy intervals is present for all women, such short intervals will often be planned with older women, according to the editorial, because of their fertility and the number of women. children wished.

"Clinicians should use patient-centered and shared decision-making strategies that respect women's desires for pregnancy, possibly at close intervals in women aged 35 or older," they said.

Although Riley tells mothers that it is ideal to wait a year before falling pregnant again, she understands that age may play a role in the mother's decision.

"I think the conversation should be that there is data suggesting that a short interval between pregnancies increases the poor outcome of pregnancy, and so people will make decisions based on this information, but at least we can always have this discussion, "she said.