Sunday, April 12, 2009

Obesity in pregnancy, conception season tied to birth defects risk

PREGNANT women who are obese are significantly more likely to give birth to children with birth defects than women of a healthier weight, according to a study conducted by researchers from Newcastle University and published in the Journal of the American Medical Association.

Also, a new study suggests that women who conceive in the spring or summer (April to July) may run a higher risk of having a baby with a birth defect, and pesticide exposure might help explain why.

Using government data on United States births between 1996 and 2002, researchers found that birth defect rates were highest among women who had conceived between April and July.

During those same months, surface-water concentrations of pesticides and other agricultural chemicals generally increased based on government water-quality assessments.

The findings, reported in the journal Acta Pediatrica, point to correlations between pesticide levels and birth defects, but do not prove a cause-and-effect relationship.

Prior research has shown that obesity significantly decreases a woman's chance of conception and increases her child's risk of a wide range of health problems. In the current study, researchers compiled the results of 39 prior studies to gain a better idea of exactly how obesity affects the risk of birth defects.

They found that obese women had more than twice the risk of bearing a child with a neural tube defect, such as spinal bifida, than women with a body mass index of 25 or less. They also had a significantly higher risk of bearing children with cleft lips or heart defects. Body mass index is a measure of obesity calculated by dividing a person's weight in kilograms by the square of their height in meters. Obesity is defined as a body mass index higher than 30, while overweight is defined as a body mass index above 25.

The researchers are planning further studies to determine precisely how a mother's obesity affects the development of her infant. One possibility is that obesity may be linked to deficiency of key nutrients such as folic acid, which is strongly linked to neural tube defects.

"Folic acid does seem to be involved," said Andrew Russell of the Association for Spinal Bifida and Hydrocephalus. "It is very important for women planning a pregnancy or likely to fall pregnant to take a folic acid supplement." Another possible cause might be undiagnosed diabetes, another known risk factor for such defects.

The implications of the study for infant health are serious, said lead researcher Judith Rankin. "Given that we are seeing an increase in the number of people who are overweight or obese, then we may see an increase in the number of babies born with abnormalities," Rankin said. "Women who are thinking about trying for a baby need to check their own weight first and then think about seeking help if they are overweight. While you are pregnant it's not the time to start a weight loss diet but it is more important to eat sensibly and healthily."

The researchers in the Acta Pediatrica study point out that, some of the chemicals tracked in the study, such as the weed killer atrazine, are suspected of causing harm to developing embryos.
PREGNANT women who are obese are significantly more likely to give birth to children with birth defects than women of a healthier weight, according to a study conducted by researchers from Newcastle University and published in the Journal of the American Medical Association.

Also, a new study suggests that women who conceive in the spring or summer (April to July) may run a higher risk of having a baby with a birth defect, and pesticide exposure might help explain why.

Using government data on United States births between 1996 and 2002, researchers found that birth defect rates were highest among women who had conceived between April and July.

During those same months, surface-water concentrations of pesticides and other agricultural chemicals generally increased based on government water-quality assessments.

The findings, reported in the journal Acta Pediatrica, point to correlations between pesticide levels and birth defects, but do not prove a cause-and-effect relationship.

Prior research has shown that obesity significantly decreases a woman's chance of conception and increases her child's risk of a wide range of health problems. In the current study, researchers compiled the results of 39 prior studies to gain a better idea of exactly how obesity affects the risk of birth defects.

They found that obese women had more than twice the risk of bearing a child with a neural tube defect, such as spinal bifida, than women with a body mass index of 25 or less. They also had a significantly higher risk of bearing children with cleft lips or heart defects. Body mass index is a measure of obesity calculated by dividing a person's weight in kilograms by the square of their height in meters. Obesity is defined as a body mass index higher than 30, while overweight is defined as a body mass index above 25.

The researchers are planning further studies to determine precisely how a mother's obesity affects the development of her infant. One possibility is that obesity may be linked to deficiency of key nutrients such as folic acid, which is strongly linked to neural tube defects.

"Folic acid does seem to be involved," said Andrew Russell of the Association for Spinal Bifida and Hydrocephalus. "It is very important for women planning a pregnancy or likely to fall pregnant to take a folic acid supplement." Another possible cause might be undiagnosed diabetes, another known risk factor for such defects.

The implications of the study for infant health are serious, said lead researcher Judith Rankin. "Given that we are seeing an increase in the number of people who are overweight or obese, then we may see an increase in the number of babies born with abnormalities," Rankin said. "Women who are thinking about trying for a baby need to check their own weight first and then think about seeking help if they are overweight. While you are pregnant it's not the time to start a weight loss diet but it is more important to eat sensibly and healthily."

The researchers in the Acta Pediatrica study point out that, some of the chemicals tracked in the study, such as the weed killer atrazine, are suspected of causing harm to developing embryos.
Nt37881

No comments: