Obesity and weight gain are some of the most common side-effects of pregnancy. Many women gain above the recommended 5 – 18 kgs during pregnancy, and many struggle with losing weight after giving birth. Factors like an increase in pregnancy hormones like progesterone, over-eating, and under-exercising, all predispose people to weight gain during pregnancy. Other factors like post-partum depression, hypothyroidism, and lack of sleep make it difficult to lose weight after giving birth. Obesity can complicate pregnancy because it is a risk factor for things like heart defects, asthma, and macrosomia (overly large) in new-born babies.
The most obvious symptom of inappropriate weight gain is being overweight or obese. Other symptoms can include:
The cause of obesity and excessive weight gain in pregnancy is not perfectly understood. From the research available, it seems that weight gain in pregnancy is due to a combination of genetic and environmental factors, as well as the behaviour of each unique woman. Hormones like progesterone rise dramatically during pregnancy, predisposing to weight gain. The additional calories and fat stored during this time allow the body to prepare for making breast milk, an energy-rich liquid that progesterone also stimulates. Weight gain is also due to the weight of the growing baby.
About 5 – 9kgs of weight are normal for an obese woman to gain during pregnancy, and 13 – 18kgs are normal for an underweight woman. Still, only 1 out of 3 women gain these amounts, with 2 out of 3 gaining more than is recommended. Many women (close to 1 out of 5) are obese at the start of their pregnancy, which also increases the likelihood that they will gain too much weight and have difficulty losing it after birth.
Certain factors increase the risk of weight gain and obesity in pregnancy, including:
Obesity and excess weight gain are usually diagnosed by taking your medical history and doing a physical exam. In the medical history, your doctor will want information on your eating, sleeping, and exercise habits; as well as any mood changes or medications you take. The physical exam will involve taking your weight and height to get your BMI, as well as an ultrasound of your abdomen to approximate your baby’s weight and size.
Blood tests are regularly taken during pregnancy, and if you have signs of obesity or excess weight gain these blood tests may occur even more frequently. Your doctor will want a lipid panel, which can test the amount of fats and cholesterols in your blood. Diabetes screening with glucose challenge tests and glucose tolerance tests are regularly done for most pregnant women, but if you have signs of excess weight gain or obesity, your doctor may want to perform these tests sooner than is typical.
Weight gain and obesity in pregnancy are usually managed conservatively, which means they are treated without medicine or surgery. Your doctor will likely recommend reducing the amount of calories you eat. Eating fewer processed carbohydrates and more proteins and vegetables is also a recommended treatment.
Moderate exercise, both cardio and weight-bearing, is recommended in most pregnant women and may be increased in those who are overweight or obese. Weight-loss medications are not usually given in pregnancy because of their unknown effects on the developing foetus.