Overview of Pregnancy & Nutrition

By recognizing the early symptoms of pregnancy, women can seek early prenatal care, which is important for both the mother and her developing baby.

Pregnancy Image - Masterfile

Women who are pregnant are encouraged to eat a variety of foods. Weight gain is a normal and healthy part of pregnancy—especially during the second and third trimesters (i.e., the 14th week through the end of pregnancy). Most women gain a normal amount of weight by eating healthfully, staying active, and allowing their appetite to guide their food intake.

Physicians usually recommend general guidelines for healthy eating. During pregnancy, the diet should include the basic nutrients necessary to meet the demands of the developing fetus. Junk food should be avoided, because it provides little more than empty calories. For women who normally do not follow a healthy diet, pregnancy is a good time to start.

Healthy eating helps reduce the risk for premature birth and helps ensure that the baby will have a healthy birth weight and will not be born with infections or other problems. It also reduces the risk for complications during pregnancy and delivery and builds up fats and fluids for use during breastfeeding. It's important to continue to eat well after the birth too, especially if breastfeeding.

Weight Gain during Pregnancy

Pregnancy is no time to diet. Every woman is different—depending on body type and weight before conception and other factors—but most women who deliver healthy babies gain about 25 to 35 pounds or more during pregnancy. Women who are underweight prior to pregnancy should gain a little more, and overweight women, a little less.

Women who do not gain enough weight have an increased risk for delivering babies with low birth weight (less than 2500 gm, or 5.52 pounds). The National Institutes of Health considers low birth weight (LBW) a major public health problem in the United States. LBW is a major cause of infant mortality, as well as many childhood developmental, physical, and psychological problems.

Although infant mortality in the United States has declined over the past several decades, it is still a significant public health problem. Among African Americans, approximately 13 percent of newborns are underweight; among Hispanics, 6 to 9 percent; among Asian Americans, 5 to 8 percent; and among Caucasians, approximately 6 percent of newborns are underweight. Racial variations in birth weight may reflect socioeconomic differences and this is an important focus of research funded by the National Institutes of Health.

Babies who are underweight are at risk for physical and psychological childhood disorders:

  • They are more likely to experience asthma, respiratory tract infections, and ear infections.
  • Babies who are born weighing less than 1000 gm (2.2 lbs), are at greater risk for cerebral palsy (a neurological abnormality).
  • They are more likely to score low on intelligence tests and are more likely to have delayed development.

Gaining too much weight can also be a problem. It can make pregnancy an unpleasant experience, causing backache, leg pain, varicose veins, and fatigue. Excessive weight gain may lead to hypertension and diabetes and can be difficult to lose after delivery.

Excessive weight gain may also cause problems for the baby. Technically, an overweight baby is one who weighs more than 4500 gm, or 9.9 lbs. Large babies make vaginal deliveries difficult, increasing the risk for cesarean section, and may have an increased risk for health problems later in life (e.g., obesity, adult rheumatoid arthritis, diabetes).

Women who are gaining too much weight during pregnancy should follow the guidelines for healthy eating; avoid foods that do not have nutritional value; and consult a doctor, midwife, or dietitian.

Every woman's body is different, and determining how much weight a woman should gain is an estimate. The following table provides recommended weight gain based on a woman's body mass index (BMI) at the beginning of the pregnancy. Body mass index measures the weight-to-height ratio and is calculated by dividing weight (measured in kilograms) by the square of height (in meters). A normal BMI ranges from 19.8 to 26.

For women whose BMI is normal, the recommended weight gain over the course of the pregnancy is 25 to 35 pounds. Women who are underweight, or have a low BMI, should gain more weight, and women who are overweight, or have a high BMI, should gain less.

Recommended Weight Gain

Low (BMI < 19.8) - 12.5-18 kg (28-40 lb)
Normal (BMI 19.8-26) - 11.5-16 kg (25-35 lb)
High (BMI 26-29) - 7-11.5 kg (15-25 lb)
Obese (BMI > 29) - 6 kg (15 lb)

Pregnant women should consult a physician or midwife if they have questions about how much weight they can expect to gain on a week-to-week basis during pregnancy. Generally, little weight is gained during the first trimester (3 or 4 lbs.). The most weight (about 12 to 14 lbs.) is gained during the second trimester. In the third trimester, women should expect to gain about 8 to 10 lbs.

Publication Review By: the Editorial Staff at HealthCommunities.com

Published: 31 Oct 2000

Last Modified: 01 Oct 2015