PERINATAL STRESS
During the 1970s, attempts were made to have stress-free births,
but this proved to be potentially harmful to neonates. Late-term fetuses and neonates
are capable of producing large quantities of catecholamines that help them prepare
for birth, adapt to extrauterine life, and cope with hypoxia. Animals deprived of
a catecholamine surge at birth are less likely to survive hypoxia than those with
a catecholamine surge. Catecholamines aid in the clearance of liquid from the lungs
before birth, which improves lung compliance after birth. Catecholamines also are
important for the release of surface-active material (SAM) from alveolar type II
cells. During asphyxia, catecholamines maintain cardiac output and redistribute
blood flow from the periphery to the heart, brain, and adrenal glands. They also
increase arterial blood pressure and slow the heart rate, which reduces myocardial
oxygen consumption.[1]
Catecholamines are required
for breakdown
of stored fuels.[2]
Infants delivered by cesarean
section without maternal labor have lower blood glucose concentrations than those
born after labor. Blood flow to peripheral organs is higher after vaginal delivery
and is related to plasma catecholamine concentrations. Neonates with elevated catecholamine
concentrations have higher Apgar scores than those who have low concentrations of
these amines in their blood. Stress is an important part of the transition from
intrauterine to extrauterine life.
