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Does Stress During Pregnancy Affect Size of Baby?

A new study reveals prenatal stress has a physical effect on babies. Researchers report prenatal maternal stress in late gestation leads to slower growth of the offspring both in utero and during infancy.

Researchers from The Universities of New Mexico and Göttingen have now proposed a hypothesis that largely predicts why there are highly variable patterns in the growth rates of disadvantaged offspring across 719 studies on 21 mammal species.

“The idea is that prenatal stress affects offspring in two different ways depending on the timing of the stressor during pregnancy—yielding different outcomes before birth, after birth, and after weaning” says Andreas Berghänel, evolutionary anthropologist at The University of New Mexico and lead author of the study.

For example, prenatal maternal stress late in gestation causes mothers to invest less energy in their offspring, which leads to slower grow in the womb and during infancy. Once the baby has reached nutritional independence, however, they are no longer affected directly by their mother’s provisioning, and consequently grow at the same rate as non-disadvantaged offspring. Thus, maternal stress late in gestation leads to slow growth during dependent phases, but doesn’t affect growth later.

By contrast, prenatal maternal stress early in gestation can cause the fetus to be entirely reprogrammed to deal with a reduced life expectancy. To “make the best of a bad job,” the early challenged offspring switches to an accelerated pace of life and grows and matures faster than unchallenged offspring to ensure that it reproduces before it dies. Once set on the fast track, the offspring under early prenatal maternal stress remain on this trajectory even after weaning and therefore overshoot the usual body size for age throughout development.

“We found that stress during late gestation reduces offspring growth during dependence, resulting in a reduced body size throughout development, whereas stress during early gestation results in largely unaffected growth rates during dependence but accelerated growth and increased size after weaning,” says Berghänel.

Dr. Aristotle's Comment:

3 Examples of Stress Relief During Pregnancy

1. Restoring Pelvic Balance and Poor Posture

Pregnant women often have issues with their pelvic balance and back pain due to the extra weight they must carry in the front of their body. Many women experience pelvic structural changes during their pregnancy. When the pelvis is not in balance, it can restrict the amount of room that the developing baby has. We address imbalances of the spine to lessen low back pain.

2. Reducing Pregnancy Symptoms

Care helps reduce some of the uncomfortable symptoms associated with pregnancy. Regular care throughout pregnancy can help women maintain their health during pregnancy, relieve joint and neck pain and control the symptoms of nausea.

3. Reducing Labor and Delivery Time

Since women who receive regular care are taking care of their nervous system, many have found their bodies are better prepared to handle the childbirth process. When the nervous system is working properly, the whole body is working as it should be. With this in mind, many women who receive chiropractic care during pregnancy have shorter labor and delivery times.

The body undergoes a number of changes during pregnancy. This can leave any woman feeling uncomfortable as her body handles the physical and hormonal changes that pregnancy brings. Of course, many women are also worried about the health and safety of their baby during this important developmental time. In order to take the best care possible of both mom and baby, it is important to take care of your body with regular visits.

Pregnant moms who take the time to keep their body in balance during pregnancy will find that their overall pregnancy can be more comfortable and enjoyable as they keep their bodies — and their babies — healthy.


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