Increasing trends in maternal obesity could impact mother and child

The epidemic of obesity is felt in prenatal clinics and delivery rooms around the world with a worrisome trend in high-risk pregnancies that could impact mother and child, according to Patrick M. Catalano, MD, the Dierker-Biscotti Women's Health and Wellness Professor and Director of the Center for Reproductive Health at MetroHealth and Director of the Clinical Research Unit of the Case Western Reserve University. Dr. Catalano collaborated with a team of clinicians and scientists from around the world to address these issues in a series of review papers on maternal obesity published this month in The Lancet Diabetes and Endocrinology.

"The management of obesity in pregnancy begins before, during and after pregnancy," said Dr. Catalano. "There is limited evidence based data on how best to mitigate adverse metabolic effects of obesity on mothers (spontaneous miscarriage, gestational diabetes, pre-eclampsia and need for cesarean delivery) and their offspring (congenital anomalies, neonatal adiposity and risk for childhood obesity) once a woman is pregnant. Basic questions as to what is the optimal diet or weight gain during pregnancy need to be addressed. In the interim, until a comprehensive potentially personalized life-course approach is instituted, efforts during pregnancy will by necessity be aimed at recognizing and mitigating the adverse metabolic consequences of maternal obesity during pregnancy on both the mother and her child."

He said that lifestyle modifications such as healthy eating, physical activity and behavioral modifications during pregnancy have had limited benefits on improving adverse perinatal outcomes, with the exception of reducing excessive gestational weight gain, on the average of two to five pounds in obese women.

The review was a collaborative effort between Dr. Catalano and his colleagues in Hong Kong, Brazil and Australia so that recommendations could be based on an understanding of the worldwide impact of obesity on pregnancy. "There is no doubt that we are all seeing an increase in pregnancy-related problems that are due to obesity all over the world," said Dr. Catalano.

The review by Dr. Catalano and his international colleagues focusses on the clinical management of obesity in pregnancy and how to reduce risks to mother and child. "Obesity is associated with reduced fertility, and pregnancies complicated by maternal obesity are associated with adverse outcomes, including increased risk of gestational diabetes, pre-eclampsia, pre-term birth, instrumental and caesarean births, infections, and post-partum hemorrhage," the authors wrote in the paper. "The medical and obstetric management of obese women is focused on identifying, addressing, and preventing some of these associated complications, and is a daunting challenge given the high percentage of patients with obesity and few therapeutic options proven to improve outcomes in this population."

There are no standard guidelines for the management of obesity in pregnancy, added Dr. Catalano. The American College of Obstetricians and Gynecologists recommends that all pregnant women follow a healthy diet, and consider at least half an hour of moderate physical activity per day during pregnancy. But Dr. Catalano said that obese pregnant women represent a relatively new high-risk population that will call for the development of additional tools to help these women reduce these risks before, during and after pregnancy. The Case Western scientists are also carrying out a study to determine whether lifestyle changes initiated in the post-partum period will help reduce the risks for a woman's next pregnancy.

In 2008, there were almost three overweight or obese women of childbearing age for each underweight woman, according to Dr. Catalano and his colleagues. They are suggesting that clinicians working with overweight or obese women of childbearing age offer pre-conception weight management to improve metabolic health and fertility and decrease early loss of a pregnancy. There should also be screening for diabetes. Once pregnant, women should be instructed on how to maintain a healthy gestational weight gain (through healthy eating and exercise). Studies suggest that 50 to 60 percent of obese women gain more weight in pregnancy than is recommended by the Institute of Medicine (IOM). The review also suggests that clinicians screen for fetal structural problems.

In mid-pregnancy, the experts say that clinicians should also screen for gestational diabetes and pre-eclampsia, and towards the end of pregnancy there should be an assessment of fetal overgrowth (which is more common among obese pregnant women.) The labor and delivery team should also be aware of the increased risk for a caesarean delivery. Some studies have shown that the induction failure rate is twice as high in obese women compared with women who entered pregnancy with a healthy weight. Obese women in the post-partum period are also at higher risk for venous thromboembolism, difficulty with lactation, and depression.

New mothers struggling with obesity may also find it more difficult to breastfeed their babies.

Dr. Catalano and his colleagues believe that other than beginning a life-course effort in reducing obesity in adolescence as discussed in the other reviews in this series, the post-partum period may well be the best opportunity to help ensure the move towards a healthy body weight and lifestyle for a subsequent pregnancy, which also effects the whole family. "There is growing evidence that offspring of obese mothers are at high risk for excessive weight in childhood," said Dr. Catalano.

The Case Western and MetroHealth Maternal-Fetal medicine expert said that it is still not clear what lifestyle interventions will work to reduce risk factors to mother and child. "What can we do? We are trying to study that now. The ideal is to assist a woman to improve their metabolic health before she gets pregnant. But what is the best diet? Will there be different approaches in other parts of the world? What about managing a healthy weight gain during pregnancy? How can we work together to reduce birth defects? We have a long way to go but recognizing the magnitude of the problem is the first step in the right direction. We need to develop a comprehensive life-course approach to the problem utilizing public health measures, the food industry in addition to primary care health provides, obstetricians, pediatricians and allied health professionals such as nutritionists and exercise physiologists. We must address these questions for the sake of our patients and generations of children yet to be born."