Effects of prenatal stress can last for generations

Pregnancy can be a stressful time, with negative effects that can last through labor, delivery and even through family generations, a new study shows.

Mild to moderate stress during pregnancy had a compounding effect across four generations of laboratory rats, resulting in premature births and other complications, according to findings published in the journal BMC Medicine.

“We show that stress across generations becomes powerful enough to shorten pregnancy length in rats and induce hallmark features of human preterm birth,” said Gerlinde Metz, senior author of the article, in a statement. “A surprising finding was that mild to moderate stress during pregnancy had a compounding effect across generations. Thus, the effects of stress grew larger with each generation.”

Researchers from the University of Lethbridge in Canada set out to investigate how stress influences preterm birth, one of the leading causes of neonatal death. They studied rats because there is generally little variation between the length of pregnancies in rats.

In the first generation of rats, the rats were subjected to stress late in pregnancy. The following two generations were divided into two groups: one that was stressed and a second that was left alone. The daughters of the stressed rats had shorter pregnancies than the daughters of the control group. Even the grand-daughters of the stressed rats had shorter pregnancies. In addition to the shorter pregnancies, the rats whose grandmothers and mothers experienced stress had higher glucose levels and weighed less than those who were not stressed.

A way to reduce stress during pregnancy is by obtaining regular, consistent prenatal care and attending childbirth preparation classes, according to prenatal education experts. Pregnant women typically visit the doctor once a month from weeks four through 28, twice a month during weeks 28 through 36 and weekly from week 36 until delivery; women considered high risk usually see their doctors more often. Early and regular prenatal visits means health care providers are better able to monitor their pregnant patients’ health and the growth of the baby.

Most hospitals offer childbirth preparation classes for women in their third trimester of pregnancy; they are encouraged to attend with their partner or support person so both can learn what to expect in the delivery room. The classes include instruction on the stages of labor, breathing techniques, pain management, vaginal and C-section deliveries, newborn care and infant safety.

“Childbirth classes go a long way toward building confidence in your body’s ability to go through labor and deliver a baby,” says Marshelle Santoro, a prepared childbirth instructor at Advocate Good Samaritan Hospital in Downers Grove, Ill. “Feeling confident and prepared can decrease stress during pregnancy.”