The arrival of a new baby is inherently stressful. And for mothers navigating careers or jobs that don’t don’t offer much in the way of paid maternity leave, that stress can manifest tenfold. Maternity leave has come a long way in many countries, but it’s not always guaranteed, and this can impact the health of both mother and child.

The Study

Published in the American Economic Journal: Economic Policy, the study looked at data on the health of mothers in Norway before and after paid maternity leave became mandated by law in 1977. The change in policy offered a unique opportunity to examine an aspect of maternal health for which literature is sparse. “Estimating causal effects of maternity leave on health is difficult as many things need to come together to get reliable results,” says Aline Bütikofer, PhD, study researcher and economist at the Norwegian School of Economics. “First, we need a natural experiment that allows estimating causal effects. The sharp change in access to paid maternity leave in 1977 in Norway provides such a natural experiment.” Researchers combined birth registry data with biometric data like blood pressure, cholesterol levels, body mass index, and rates of diabetes, as well as self-reported rates of pain, mental health, exercise habits, and tobacco use. “Many of the measurements we look at are closely related,” Bütikofer says. “For example, a high BMI is correlated with higher blood pressure, the likelihood of having back pain, and also stress. I would therefore say that the most important finding is that access to paid maternity leave seems to affect many dimensions of both physical and mental health.” The study findings show women who gave birth after 1977 experienced better health overall as they approached middle age. This was especially true for women who worked low-income jobs. These women were less likely to smoke or experience high blood pressure, had lower BMI, and were more likely to exercise regularly.

The United States is one of the only industrialized nations without a paid family medical leave plan in place. A 2014 report from the United Nations’ International Labor Organization found the U.S. to be one of two countries, out of the 170 included in the report, that provide no cash benefit of any kind to women during maternity leave. Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes. In the U.S., employers with 50 or more employees must allow parents 12 weeks of job-protected leave annually to care for a newborn. But this doesn’t guarantee pay, and the length of maternity leave varies across the country. According to the report, 12 weeks was found to be the shortest amount of time mandated by any developed country. Peace Nwegbo-Banks, MD, an obstetrician and gynecologist in Texas, points out that paid leave not only prioritizes the physical health of a new mother, but provides security and bolsters mental health, as well. “Paid maternity leave gives families financial security as they navigate the journey of parenthood,” Nwegbo-Banks says. “There are many instances when women have to return to work too soon after delivery or C-section instead of bonding with their newborn. This is of course not ideal and surgical/postpartum complications can arise. The hormonal and physiological changes that take place after delivery are extensive and new parents deserve ample time to adjust.” While the impact of paid maternal leave in Norway can’t be applied directly to the U.S., due to institutional differences between the two countries, Bütikofer notes one important way the study findings could be useful. “Understanding the effects of this policy change might be important for the U.S. context since the reform extended leave benefits from a level similar to what the U.S. offers today under the Family and Medical Leave Act,” Bütikofer says. “Hence, it is not unlikely that we could see an improvement in maternal health for low-income mothers if they would have access to some months of paid leave.”

The Future of Family Leave

With the health of mothers in mind, better parental leave policies are necessary. In addition to a minimum of 12 weeks of paid leave after the birth of the baby, Nwegbo-Banks points to the importance of adequate screenings for depression, anxiety and other postpartum challenges that may arise, as well as easily accessible lactation consultation and support. These types of changes can affect more than just the health of new moms. Longer maternity leave has been linked to a reduction in infant and child mortality, as well as decreased risk of infant re-hospitalization. Countries around the world have long been aware of the importance of this time period, offering anywhere from six to 86 weeks of paid leave for new parents. Without a paid parental leave plan in place at all, it’s clear the U.S. has ample room for improvement. Using these study findings as evidence, enacting new policy could have a life-changing impact on health outcomes for both mother and child.