structural:summarization, information:extraction
Weight gain

The amount of healthy weight gain during a pregnancy varies. Weight gain is related to the weight of the baby, the placenta, extra circulatory fluid, larger tissues, and fat and protein stores. Most needed weight gain occurs later in pregnancy.

The Institute of Medicine recommends an overall pregnancy weight gain for those of normal weight (body mass index of 18.5–24.9), of 11.3–15.9 kg (25–35 pounds) having a singleton pregnancy. Women who are underweight (BMI of less than 18.5), should gain between 12.7 and 18 kg (28–40 lb), while those who are overweight (BMI of 25–29.9) are advised to gain between 6.8 and 11.3 kg (15–25 lb) and those who are obese (BMI ≥ 30) should gain between 5–9 kg (11–20 lb). These values reference the expectations for a term pregnancy.

During pregnancy, insufficient or excessive weight gain can compromise the health of the mother and fetus. The most effective intervention for weight gain in underweight women is not clear. Being or becoming overweight in pregnancy increases the risk of complications for mother and fetus, including cesarean section, gestational hypertension, pre-eclampsia, macrosomia and shoulder dystocia. Excessive weight gain can make losing weight after the pregnancy difficult. Some of these complications are risk factors for stroke.

Around 50% of women of childbearing age in developed countries like the United Kingdom are overweight or obese before pregnancy. Diet modification is the most effective way to reduce weight gain and associated risks in pregnancy.