NEW ORLEANS — Women seeking infertility treatment should be warned about the increased risks associated with pregnancy at older ages, according to Barbara Luke, Sc.D., professor at the School of Nursing & Health Studies, University of Miami at Coral Gables in Florida.
In an analysis of more than 8 million singleton live births to women aged 30–54 years, her study found significantly increased risks of pregnancy complications and adverse outcomes as women aged.
The study used the U.S. Birth Cohort Linked Birth/Infant Death data set of singleton live births of 20 weeks' gestation or more between 1995 and 2000. Births to women aged 30–34 years were the reference, and the study controlled for maternal race, smoking, macrosomia, and breech or malpresentation. The highest risks were seen in women aged 45 years and older, but “many risks are significantly elevated by age 35–39 years,” Dr. Luke said in an interview.
Looking at the overall population, the study found that two of the greatest health risks for older pregnant women—chronic hypertension and diabetes—may be present even before pregnancy. Chronic hypertension (hypertension developing before pregnancy or up to 20 weeks' gestation) was highest in women aged 45 or older (adjusted odds ratio of 3.7 for primiparas and 4.89 for multiparas), as was diabetes (AOR of 2.19 for primiparas and 2.58 for multiparas). Pregnancy-associated hypertension, defined as developing after 20 weeks' gestation, was another important risk in this age group (AOR 1.55 for primiparas and 2.13 for multiparas), Dr. Luke said.
Similarly, premature rupture of membranes (PROM), premature birth (less than 32 weeks' gestation), and infant death were markedly increased by age 35–39 years, with the greatest risk in women 45 years and older (AOR 1.02, 2.11, and 2.68, respectively, for primiparas and AOR 1.38, 1.77, and 1.92, respectively, for multiparas).
The risk of precipitous labor and stimulation of labor decreased with age, but the risk of excessive bleeding, dysfunctional labor, induction of labor, and prolonged labor all increased as women got older.
Primary cesarean section increased with age in both primiparas and multiparas (AOR 3.15 and 2.65 in the oldest age group), while forceps, vacuum, and vaginal deliveries actually decreased with age in the primiparous group (AOR 0.90, 0.73, and 0.32, respectively), said Dr. Luke. In the oldest multiparous group the risk of repeat section increased (AOR 1.56), forceps and vacuum deliveries increased (AOR 1.29 and 1.08), and vaginal births after cesarean section decreased (AOR 0.64).
“This is particularly worrisome since with C-section there is a doubling of the neonatal mortality rate and an increased risk of stillborn and placental complications in subsequent pregnancies,” she noted.
There is also evidence of long-term health implications for women who develop pregnancy complications such as preeclampsia and preterm birth, Dr. Luke concluded.