Mother`s exposure to passive smoking dangerous for baby: Study

Updated: Mar 18, 2010, 00:00 AM IST

Washington: Babies born to mothers with obesity and exposed to passive smoking are at a greater health
risk because they reduce oxygen supply to the unborn child,
doctors have said.

A team led by pediatricians from the National Research
Centre in Cairo have found that obesity and passive smoking
are risk factors for the unborn child, Science Daily reported.

"Foetal development during the last half of pregnancy
depends on maternal metabolic adjustments detected by
placental hormones and the subsequent oxygen and nutrient
supply," lead author Abd ElBaky said.

ElBaky said, "If these are compromised, through obesity
issues or exposure to tobacco smoke, then serious problems can

"The mechanisms that link the raised levels of immature
blood cells in the samples to obesity and passive smoking are
complicated. Obesity is known to affect metabolism, hormones,
blood pressure and other physiological factors".

This conclusion is based on evidence of elevated levels
of nucleated red blood cells in the umbilical cord reported in
the International Journal of Food Safety, Nutrition and Public

The team compared NRBC count in umbilical blood in three
groups. Group I neonates (29 infants) were born to obese
mothers. Group II (21 babies) were born to mothers exposed to
tobacco smoke during pregnancy and a control group III (15

The researchers found that NRBC count was higher in
groups I and II compared to the control group III. They also
found that maternal body mass index (BMI) and infant birth
weight were significantly higher in group I.

"Raised levels of NRBCs are indicative of a degraded
oxygen supply to the baby during the pregnancy," ElBaky said.
Tobacco smoke inhalation whether direct or indirect may
affect the amount of oxygen reaching the unborn child, because
haemoglobin is poorly oxygenated.

Nicotine can also cause narrowing of blood vessels,
vasoconstriction, and so reduce oxygen supply through that
mechanism too.

The team speculates that even apparently healthy newborns
of obese mothers and passive smokers may suffer subtle
effects of the reduced oxygen levels during pregnancy.

"We recommended that every effort to control maternal
obesity and prevent exposure to tobacco smoke be made," the
team said.

"Smoking regulations in the workplace and at home should
be enforced strictly for the well-being of our infants," they