With more couples waiting until later in life to start families, staying informed and evaluating risks is an important first step in the family-planning process.
A new study conducted by Researchers at the University of British Columbia and the Harvard T.H. Chan School of Public Health provides a great place for new families to start their planning. The researchers explored the risks associated with spacing out pregnancies, as well as the ways these risks affect women of different age groups.
While perhaps the biggest takeaway was that shorter intervals between pregnancies increases risks for both the mother and baby, the researchers also found that once the mother is over 35, the mother and baby are affected in different ways.
“Our study found increased risks to both mother and infant when pregnancies are closely spaced, including for women older than 35,” said lead researcher Laura Schummers. “The findings for older women are particularly important, as older women tend to more closely space their pregnancies and often do so intentionally.”
Worth the wait
To assess the risks associated with intervals between pregnancies -- and the ways they differ between age groups -- the researchers evaluated hospitalization data, billing codes, birth records, census records, and prescription data for infertility information. In total, they analyzed nearly 150,000 pregnancies, making it the largest study of its kind.
While waiting more time in between pregnancies proved to be less of a risk for mothers in both major age groups -- 20-34 and 35+ -- the researchers’ findings are important for anyone looking to plan a family.
For women aged 35 years and older, the risks were more serious for them, as opposed to for the baby. Women in this age group who waited 18 months in between pregnancies reduced their risk of maternal mortality or severe morbidity to 0.5 percent, whereas women who waited just six months in between pregnancies were at a 1.2 percent risk.
According to the Centers for Disease Control and Prevention (CDC), severe maternal morbidity affected over half a million women in the United States in 2014, and it has been steadily increasing over the last few years, further proving the significance of the researchers’ findings.
Preterm birth -- delivering the baby before 37 weeks -- was also a concern for women in the 35+ age group, though more time between pregnancies also helped reduce that risk. Those who waited the 18 months were at a 3.4 percent risk of early delivery, while those who waited just six months were at a six percent risk.
For women in the younger age group, preterm birth was the biggest risk. Women who took more time in between pregnancies -- reaching that 18-month mark -- were found to have a 3.7 percent risk of early delivery, while those who waited six months were at an 8.5 percent risk.
“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 following a birth,” said Dr. Sonia Hernandez-Diaz, professor of epidemiology at Harvard T.H. Chan of Public Health.
Parents waiting to have kids
Last summer, researchers at Stanford University conducted a study that found that many consumers are waiting until later in life to have kids.
The study analyzed data from the National Vital Statistics System -- a dataset that tracked births in the country from 1972 through 2015. Over the course of the study, the average age of a father at the time of a child’s birth increased from 27.4 to nearly 31 years old. Additionally, the study found that maternal ages have increased even more so than fathers’ during the same timeframe.
The researchers chalked it up to the ever-changing social climate and more widespread contraception.
“We’ve seen a lot of changes in the last several decades,” said lead researcher Dr. Michael Eisenberg. “Women have become more integrated into the workforce. This seems to be reflected in an increasing parity in parental ages over the last four decades.”