A new study has found that infants of overweight or obese mothers have a higher chance of being oxygen-deprived or having breathing problems at birth. The heavier the mother, the higher the risk is for the child to experience these issues, the research states.

Researchers at the Karolinska Institutet in Stockholm analyzed data of nearly 1.7 million babies born between 1992 and 2010 in Sweden, including information about mothers’ weights and heights, in order to understand the link between a mother’s body mass index (BMI) and severe asphyxia-related outcomes in infants. Asphyxia is a condition of oxygen deprivation in the body caused by abnormal breathing. The researchers measured the Apgar scores of the babies, which assesses heart rate, breathing, muscle tone, skin color, and activity. A low Apgar score typically means there is a lack of oxygen, Dr. Martina Persson, the lead author of the study, said.

In the past, studies have shown that overweight or obese mothers are more likely to give birth to infants with a wide range of complications. Women with a BMI of over 30 might have a higher risk of miscarriage, gestational diabetes, blood clots, and infection. Overweight women are also more likely to give birth to a heavier child that has a higher chance of health problems later in life, such as diabetes, obesity, and various birth defects.

“Maternal obesity is associated with a number of complications during pregnancy and delivery, but the underlying mechanism is not fully understood,” Dr. Marie Blomberg of Linkoping University in Sweden, told Reuters. The researchers hope that by pinpointing these issues that can arise from an overweight pregnant mother, women will take steps to control their weight before giving birth, as they do with refraining from smoking and drinking in order to prevent complications for their children.

The authors also found that a newborn’s risk of seizures increased with higher rates of BMI in mothers; infants of severely obese mothers were more likely to have a seizure than those born to normal-weight mothers. In addition, infants of obese mothers often showed signs of meconium aspiration: “Meconium release is a sign of fetal stress,” Persson told Reuters. “Meconium aspiration may give severe breathing problems in the newborn and is associated with birth asphyxia and low Apgar scores.”

Persson urges mothers-to-be to watch their weight, especially during pregnancy, when food cravings can often lead to abnormal weight gain beyond what is within healthy pregnancy weight limits. “Enjoy your pregnancy! Try to eat healthy and be physically active. Seek support from your midwife in order to change bad eating habits and try not to gain too much weight during pregnancy,” she said.

Source: Persson M, Johansson S, Villamor E, Cnattingius S. “Maternal Overweight and Obesity and Risks of Severe Birth-Asphyxia-Related Complications in Term Infants: A Population-Based Cohort Study in Sweden.” PLOS Medicine. 2014.