Pregnant women can stop worrying that the stressors and anxieties present in their hectic lives today may hurt their babies. On the contrary, a study by researchers from Johns Hopkins Bloomberg School of Public Health in Baltimore, Md., suggests that a bit of stress and anxiety during pregnancy may actually be beneficial.
In a study of 137 healthy pregnant women with low-risk normal pregnancies, researchers found that those who reported moderate levels of anxiety and stress between weeks 24 and 32 of pregnancy had children who were somewhat more advanced in their mental and motor development at two years of age.
Overall, Janet DiPietro and colleagues also failed to see any ill effects of prenatal stress and anxiety on the children's emotional development and behaviour, based on objective measures.
The few existing studies that have examined the impact of stress during pregnancy on child health and development have "many flaws, including simply relying on asking mothers how their children behave," Dr. DiPietro said. "Maternal anxiety colours women's perceptions of their children such that stressed women more often report children to be more difficult. This is why we focused on objective outcome measures," she explained.
The study found that children of women who reported more negative feelings about being pregnant had somewhat lower behaviour and emotional scores.
But, overall, this study should put pregnant women's minds at ease and help them stop "worrying about worrying," Dr. DiPietro said. "The reason to avoid stress is because it can be bad for [the mothers]and it's not a good idea to go into labour/delivery and child rearing exhausted," she emphasized.
There is a biological basis that explains the finding that moderate stress is not harmful and may be beneficial for the baby. Chemicals produced by stress have a well-known influence on organ growth and development, the authors note in the current issue of Child Development.
Alternatively, Dr. DiPietro suggested that, "it might be a simple genetic transmission and/or an environmental one; women who are stressed in today's world may be the type of women who challenge or push themselves; they may in turn challenge/push their babies to develop faster."
It should be noted, however, that the women in this study did not have significant mental health problems -- they were not depressed and they did not have anxiety disorders -- but rather reflect the range of "normal" stress and anxiety common to working women with multiple roles and responsibilities.
"It's possible the results would be different if the study had included women with more chronic, physical or severe stress in their daily lives," Dr. DiPietro added.