(RxWiki News) Pregnant women who are severely overweight may face a number of risks to their own health. But it's not only these heavy mothers who are put at risk; that extra weight also may be harmful to their baby.
Very heavy women were more likely to give birth to babies experiencing low levels of oxygen at birth, or to babies who had complications related to not having enough oxygen, researchers found.
"Ask your doctor for a healthy weight goal before becoming pregnant."
This study was led by Martina Persson, MD, of the Karolinska Institutet in Stockholm, Sweden.
Dr. Persson and colleagues studied a Swedish cohort of women from the Medical Birth Register that included all single births of live children born in Sweden from 1992 to 2010. They looked at the measured weight of the mothers at their first visit to the physician before giving birth, as well as the Apgar scores of their newborns.
Apgar scores are quick tests given to babies immediately after birth. At one minute, the test tells doctors how the baby tolerated the birth process, and at five minutes, how the baby is doing outside the womb. The test may also be done at 10 minutes after birth to see if the baby is faring better. The score is based on 10 points and assesses things like breathing, color and muscle tone. Babies who get 7 to 10 points are considered healthy.
The researchers singled out babies born with an Apgar score of three or lower at five minutes and 10 minutes after birth.
A total of 1,380 infants had an Apgar score of 0 to 3 at five minutes. At 10 minutes after birth, 894 babies had an Apgar of 0 to 3.
The authors noted that the majority of babies with low Apgar scores were born to mothers of normal weight. However, they also found that the heavier the mother was, the more likely it was that her child would have a low Apgar score.
Overall, the researchers found that the rates of low Apgar scores increased with the mothers' body mass indices (BMI) — a measure of body fat based on height and weight.
In this study, a BMI of 25.0–29.9 was associated with a 55 percent increased risk of a baby having a low Apgar score at five minutes.
Women who were obesity grade I (BMI of 30–34.9) and grade II (BMI 35.0–39.9) had a two-fold increased risk of having a child with a low Apgar score. Women with obesity grade ΙII (BMI greater than or equal to 40.0) had more than a three-fold increased risk of having a baby with a low Apgar, the researchers found.
Many of the babies had asphyxia, which means they were oxygen deficient. Mothers who had babies with low Apgar scores at five minutes after birth often had babies with asphyxia-related problems.
An example of an asphyxia-related problem is meconium aspiration — a dangerous condition in which the baby inhales some of its first stool, which was expelled into the amniotic fluid, and develops breathing problems as a result. Another asphyxia-related problem is neonatal seizure, which is when abnormal electrical stimulation occurs in the brain of an infant deprived of oxygen.
The researchers speculated on what may cause very heavy moms to have babies born with asphyxia or asphyxia-related problems.
They noted that infants of obese mothers are more likely to have traumatic deliveries, be large for their gestational age (large for the time they spent in the womb), and more likely to spend time in the neonatal intensive care unit for problems at birth.
The study authors speculated that the problems infants born to overweight mothers face may be due to shoulder dystocia (a baby’s head comes out, but the shoulders remain stuck inside the mother) or other issues related to babies born unusually heavy at birth.
The investigators noted that one limitation of their study was that they did not have any data on how these babies fared after their low Apgar scores and when they were treated by medical personnel on hand at the time.
“Obesity in of itself is a major risk factor for a host of medical conditions, “ Dr. Andre Hall, an obstetrician in Fayetteville, NC told dailyRx News. “Babies with asphyxia, as an independent risk factor associated to obese women, may be yet another one. This is a finding that does not have a clear correlation, as is admitted by these authors.
“There are a number of very good reasons that women contemplating pregnancy should improve their health and lower their weight,” Dr. Hall said. “And although the reason for the association between obesity and birth asphyxia may not be well understood, this is yet another reason that supports the need for a healthy living.”
This study was published May 20 in PLOS Medicine.
The authors did not disclose any competing interests.