Stress and Pregnancy: What Are the Effects?

by Marjorie Greenfield, M.D.reviewed and revised by Marjorie Greenfield, M.D.

I'm writing this article during the second week of September 2001. Thousands, if not millions, of people around the world have suffered grief, anger, and tremendous anxiety in the past few days. Some of these people are undoubtedly pregnant and must deal with their distress as they try to take care of themselves and their babies-to-be. Even those who didn't have a direct or personal relationship with any of the thousands who have been lost have been changed forever by the horrible events that we witnessed.

Added to that is the worry that these intense feelings might somehow complicate the pregnancy or hurt the baby--a concern for many expectant mothers during times of stress. Here is some basic information for you about the effects of stress on pregnancy.

Can crying cause complications of pregnancy?No one knows if crying too much or feeling great sadness could cause a complication of pregnancy. Many of my patients actually have been told by well-meaning friends or relatives that their drawn-out crying spells were hurting their unborn baby in some way. However, the reality is that tragic life events happen, and you can't make yourself feel differently than you do--even if you try to ignore or suppress the emotion. Grief is part of living and loving.

I know a woman who lost one parent in her first pregnancy and her other parent while expecting her second child. Yet, even though she spent much of both pregnancies crying and grieving, her pregnancies went well medically and her children, by all accounts, are just fine.

It's hard to judge cause and effect with stress--the best thing to do is to modify what you can. Sometimes taking a positive step in the midst of tragedy can make you feel more in control and less helpless.

Research on stressStress results in the perception of emotional strain as well as physical responses, such as an increase in heart rate or stress hormones. Research on stress can be done in a number of ways: by asking subjects about their perceived level of stress, by actually measuring physical markers of stress, or by taking both factors into account. Study results on the effects of stress on pregnancy outcome have been conflicting. Some findings have shown that during the first trimester and postpartum stress is felt more deeply, or at least has a greater effect on

physical factors.

There seems to be some buffering from the severity of stress in the second trimester and even more so in the third trimester, although no one knows why this is. For instance, one study found that heart rate is less affected by stress (that is, the numbers aren't as high) in expectant mothers during the second and third trimesters compared with women who aren't pregnant. Regardless of the studies, however, it's fair to say that a pregnant woman's emotional response to stress may still be severe.

Complications of pregnancySome studies have shown a greater risk of miscarriage late in the first trimester and more birth defects if there has been severe stress in early pregnancy. Some of these findings are unreliable, though, because the patients were asked about stressors after they already knew about their pregnancy complications, which probably led to what is called recall bias--meaning that you're more like to remember an early pregnancy stressor if you had an overall bad experience in the pregnancy.

One disturbing study that looked at pregnancy outcomes after the death of an older child--which is not subject to recall bias--did find more birth defects in the offspring of mothers who were in their first trimester when the tragedy occurred. More research is needed in order to see if these associations are real and to determine how exactly stress could bring about these complications.

Other findings have indicated that more premature and small-for-date babies are born to mothers who experienced severe stress, particularly during their first trimester. Some research in this area showed medical effects of stress only in women of lower socioeconomic status or in women who tended to have pessimistic personalities.

Again, these studies often are fraught with recall bias. In many studies where researchers prevented recall bias by asking the patients about stress before pregnancy complications occurred, findings did not show a greater likelihood of complications in women who experienced critical life events.

One interesting report surveyed pregnant women in California after the Northridge earthquake--which registered 6.8 on the Richter scale--struck in 1994 and found that the earthquake was rated most stressful by mothers in their first trimester and least stressful by those in their third trimester. The ratings for the postpartum period were similar to early pregnancy.

This pattern of responses indicates that an advanced pregnancy may somewhat protect women from the psychological effects of acute stress. Pregnancy outcomes were not measured in this study.

 RELATED INFORMATION

 Stress Management in Pregnancy

 Emotions During Pregnancy

 Times of Crisis

Created September 13, 2001Reviewed and revised July 27, 2004