Study: Poorly nourished mothers may be prone to premature deliveries
Thursday, April 24th 2003, 12:00 am
News On 6
WASHINGTON (AP) _ Poor maternal nutrition just before conception and during the early days of pregnancy may be a primary cause of premature birth, according to researchers who studied the effects of undernourishment on mother sheep.
The study found that depriving ewes of food for 60 days before they mated and for 30 days afterward led to an early birth of their lambs.
Dr. Frank F. Bloomfield, a pediatrician specializing in treating premature infants at the University of Auckland, New Zealand, said the study was prompted by a rising trend of premature births among women in the United States and elsewhere. He said sheep are a commonly used animal model to study pregnancy and fetal development.
``If this data is applicable to humans then this would suggest that if women are poorly nourished around conception then they are at increased risk of preterm birth,'' said Bloomfield, the first author of the study appearing this week in the journal Science.
Dr. F. Sessions Cole, a premature baby expert at Washington University in St. Louis School of Medicine, said the study by Bloomfield and his co-authors is important because it is consistent with human studies that have suggested nutrition might play a role in premature birth.
``This supports the concept that maternal nutrition around the time of conception is important for the entire period of gestation,'' said Cole.
Premature birth is considered a major public health problem because underdeveloped babies are at increased risk of death in the first year of life and are more likely to develop heart, lung and brain disorders if they survive. The rate of preterm births in the United States has jumped in the last 20 years from about 9.4 percent of all births to almost 12 percent. About a half million premature infants are born annually in the United States.
Some of the increase in early deliveries may be linked to the fact that women are having babies at older ages and to new techniques for combatting infertility. But experts say medical science is still not certain of the precise causes.
Bloomfield said his studies with sheep suggest that undernourishment of the mother causes the early maturing of part of the hormone system in the developing fetus ``even though the undernutrition occurred months before birth.
``Our study suggests the undernourishment causes the early activation of the adrenal gland, which increases the fetal cortisol concentrations early,'' said Bloomfield. ``Labor in sheep is initiated by this surge in cortisol.''
In the study, 10 ewes who were undernourished just before and after conception delivered lambs at an average gestation period of 139 days, compared to 146 days for ewes given the normal amount of food.
``If this applies to humans, it would suggest that women who have extremes of diet or not a well balanced diet may put their pregnancies at increased risk of preterm birth,'' said Bloomfield.
The findings are consistent with a large body of studies that have found underfed women at greater risk of premature birth. Bloomfield said a study in India found that poorly nourished women tended to deliver early. Another study, dating from World War II, found that Dutch women who conceived during a time when food was very scarce tended to deliver their babies before the full term of pregnancy.
Jonathan Seckl, an endocrinologist at Western General Hospital in Edinburgh, Scotland, said in Science that the Bloomfield study has ``potentially very interesting implications in human biology.''