Obesity and Pregnancy
With alarming increase in the prevalence of obesity worldwide, World Health Organization (WHO) has considered obesity as one of the most serious global health problems of the 21st century.Obesity is defined as excessive body fat to an extent that is highly likely to impair health and increase morbidity and mortality.
Approximately 40% of women are now considered overweight or obese and since obesity has been shown to be associated with poor pregnancy outcomes, it is crucial that women are aware of the risks and complications and follow preventive measures even before planning pregnancy The gold standard when discussing obesity is BMI. Body mass index is calculated as weight in kilograms divided by the square of the height in meters. According to the World Health Organization’s definition,
lean is defined as BMI less than 18.5 kg/m2
normal weight as BMI between 18.5 and 24.9 kg/m2
overweight as BMI between 25.0 and 29.9 kg/m2
and obese as BMI greater than or equal to 30 kg/m2
In pregnancy, BMI is calculated using prepregnant weight or, if this is unknown, the first weight measured at prenatal care.
Complications associated with obesity in pregnancy are miscarriage, gestational diabetes mellitus, hypertensive disorders, fetal growth abnormalities like IUGR and other extreme, fetal macrosomia and thromboembolic complications.
Complications associated with obesity in labor are preterm labour, prolonged pregnancy, prolonged labour requiring augmentation, early amniotomy, cephalopelvic disproportion, cesarean section, and perioperative morbidity.
Complications associated with obesity in children are macrosomia, shoulder dystocia, small for gestational age, late fetal death, and congenital malformations, especially neural tube defects.
The mother’s diet during pregnancy creates a metabolic environment with increased glucose and insulin concentration leading to increased leptin synthesis that affects fetal growth and may result in later development of metabolic syndrome and cardiovascular disease, a phenomenon known as “developmental origin of adult disease”.
Obtaining normal weight before pregnancy is an ideal goal since it is of paramount importance not only for conception but also for the outcome of pregnancy.Treatment of obesity before pregnancy is a difficult task. It is essential, however, that obese women are fully informed about the risks of obesity and the benefits of weight loss. Management includes improved lifestyle by balanced diet and physical exercise. A low-calorie diet with reduced glycemic load and an adequate amount of proteins and mono-unsaturated fats reduces hyperinsulinemia in six months. Physical exercise, especially aerobic, results in weight loss as well as in the reduction of serum testosterone.
Medical treatment with anti-diabetic drugs, such as glibenclamide and metformin, might prove to be beneficial and have not proven harmful. Finally, bariatric surgery provides more permanent solutions in the event that the above-mentioned measures have failed.
Pregnancy is a period during which obesity can be relatively effectively confronted as the mother is more disposed to accept lifestyle modifications, such as balanced diet of high nutritional value which includes all food groups reducing consumption of foods with high fat content and high glycemic index. At the same time, provided that there are no medical or obstetric contra-indications, aerobic exercise of medium intensity has marked beneficial effects.Thus pregnant women are counseled to exercise on a daily basis at a moderate degree (i.e. walking, swimming, aerobics) for 30 or more minutes. Nevertheless activities that present a high risk of falls or abdominal injury as well as intense exercise must be avoided.
Furthermore, given that exercise reduces the risk of developing pre-eclampsia, glucose intolerance and gestational diabetes, overweight and obese women should be encouraged to abandon sedentary lifestyle. Pregnancy is also the ideal time for other changes in lifestyle, such as quitting smoking and giving up other harmful habits. The mother should be encouraged and motivated to consider this effort as both an investment in the maintenance of her own health as well as in that of her baby.
The postpartum period is another suitable time for the mother to adopt healthy lifestyle habits that will allow her not only to lose the excessive weight gained during pregnancy but also to achieve ideal body weight in view of a prospective pregnancy.
Conclusion-Maternal obesity constitutes a serious health risk for both mother and fetus, the impact of which increases with the degree of obesity. A non-balanced diet during pregnancy contributes not only to abnormal fetal development and subsequently increased neonatal morbidity and mortality but also to increased morbidity during childhood, adolescence and adulthood. A systematic effort for weight reduction is imperative in order to avoid transmitting obesity from generation to generation. Achieving this goal will most likely result in a sharp decrease in fetal and neonatal morbidity and mortality and will improve the outcome of offspring and of future pregnancies.