Physical or Mental Stress May Be Associated With Birth Defects or Miscarriage
Jan. 12, 2000 (Baltimore) -- Everyone wants to avoid stress. Now two studies
in the January issue of the journal Epidemiology give women who have
just become pregnant even more reason to steer clear of tension. The studies
showed that women who experience mental or physical stress around the time they
become pregnant or for the first few months of pregnancy may be at increased
risk of either miscarriage, also called spontaneous abortion, or of having an
infant with a birth defect.
"Our study shows a modest association between stressful events and
congenital anomalies [birth defects]," says Suzan Carmichael, PhD, lead
author of one of the papers, in an interview with WebMD. "It's still
somewhat preliminary given the limited number of questions we asked about
stress, but it does point the way for future studies," says Carmichael, an
epidemiologist with the March of Dimes/California Birth Defects Monitoring
Program in Emeryville, Calif.
Carmichael and colleagues collected data from mothers who had had an infant
with one of several types of birth defects and whose pregnancies ended during
1987-89 in California. They compared this data with that from mothers who
delivered healthy infants during the same time period.
Mothers were interviewed by telephone and asked about stressful exposures
during the periconceptual period, defined as one month before conception until
the end of the third month of pregnancy. "Questions about stressful events
included deaths of anyone close to the mother, separation or divorce in the
mother or someone close to her, or job loss in the mother or someone close to
her during the periconceptual period," says Carmichael. "Stressful
events during this period were associated with a moderate increase in
Dr. Paul Blumenthal, MD, associate professor of obstetrics and gynecology at
Johns Hopkins University in Baltimore, who gave objective comment on the papers
to WebMD, says, "This study was retrospective and therefore subject to
recall bias. Women who have had bad outcomes have been shown to be much more
likely to recall negative events during pregnancy than those with good
outcomes. There are also some serious statistical problems with this
The second paper looked at physical strain taking place during the time of
implantation in women experiencing their first pregnancy. Neils Henrik Hjollund
of the Aarhus University Hospital in Copenhagen, Denmark, and lead author of
the paper writes, "The analysis included 181 pregnancies. ... Physical
strain around the time of implantation was associated with later spontaneous
Women participating in the study were asked to keep a special diary during
the time they were trying to get pregnant. Information on sexual intercourse,
vaginal bleeding, and physical activity and strain was recorded. An association
between increased physical strain around the time of implantation and
spontaneous abortion was seen.
Dr. Carl Weiner, MD, professor of obstetrics and gynecology at the
University of Maryland School of Medicine, commented on this study for WebMD.
He says, "This study is provocative because of the prospectively kept
diary. Still, it's difficult to propose a mechanism whereby someone would be at
increased risk for adverse implantation because of physical strain. The
possibility can't be excluded but I'm not convinced by this study."