Healthy lifestyle habits can help you manage pregnancy weight gain and support your unborn baby's health. Also, making smart meal and exercise choices during pregnancy can make it easier to lose the extra weight after you give birth.

Healthy weight gain during pregnancy depends on various factors. That includes your body mass index, also called BMI, before you became pregnant. BMI is a measure of body mass that's based on weight and height. In general, a higher BMI number means that a person has more body fat. Other factors that play roles in how much weight to gain include your overall health and your unborn baby's health. Work with your healthcare professional to figure out what's right for you.

You also can think about these general guidelines for pregnancy weight gain:

If you're pregnant with two or more babies, you'll likely need to gain more weight. Again, work with your healthcare professional to figure out what's right for you.

You also can think about these general guidelines for pregnancy weight gain if you're carrying twins:

Being overweight or having obesity before pregnancy raises the risk of various health conditions called pregnancy complications. These include:

• Diabetes during pregnancy, also called gestational diabetes.
• Conditions that can cause high blood pressure during pregnancy, such as preeclampsia.
• The need for healthcare professionals to deliver the baby through incisions in the stomach area and uterus, also called a C-section.
• Early birth before 37 weeks of pregnancy, also called premature birth.
• Loss of a pregnancy, including miscarriage and stillbirth.
• Health conditions present at birth, also called birth defects.

Guidelines recommend a small amount of pregnancy weight gain for people who are overweight or obese before pregnancy. Some research suggests that people who are obese can safely gain less weight than the guidelines recommend. But more research is needed.

Work with your healthcare professional to figure out how much weight you should gain during pregnancy. Your healthcare professional can offer guidance on nutrition, physical activity and other ways to manage your weight throughout pregnancy.

If you're underweight before pregnancy, it's crucial to gain weight while you're pregnant. Without the extra weight, your baby might be born early or smaller than expected.

You can ask your healthcare professional what amount of pregnancy weight gain might be too much for you. Gaining too much weight during pregnancy can raise your baby's risk of health issues. These concerns include being born much larger than average. They also include complications at birth such as the baby's shoulder becoming stuck after the head is delivered. This is called shoulder dystocia. Too much weight gain during pregnancy also can raise your risk of holding on to extra weight long after pregnancy. This is known as postpartum weight retention.

Let's say your baby is born weighing 7 or 8 pounds (about 3 to 3.6 kilograms). That accounts for some of your pregnancy weight gain. What about the rest? Here's a sample breakdown:

• Larger breasts: 1 to 3 pounds (about 0.5 to 1.4 kilogram).
• Larger uterus: 2 pounds (about 0.9 kilogram).
• Placenta: 1 1/2 pounds (about 0.7 kilogram).
• Amniotic fluid: 2 pounds (about 0.9 kilogram).
• Increased blood volume: 3 to 4 pounds (about 1.4 to 1.8 kilograms).
• Increased fluid volume: 2 to 3 pounds (about 0.9 to 1.4 kilograms).
• Fat stores: 6 to 8 pounds (about 2.7 to 3.6 kilograms).

In the first 13 weeks of pregnancy, also called the first trimester, most people don't need to gain much weight. This is good news if you have upset stomach or vomiting due to pregnancy, also known as morning sickness.

If you start out at a healthy weight, you need to gain only about 1 to 4 pounds (0.5 to 1.8 kilograms) in the first few months of pregnancy. You can do this by eating a nutritious diet — no extra calories are needed. A nutritious diet includes plenty of fruits, vegetables, whole grains, lean protein and healthy fats.

Steady weight gain is more important during weeks 14 to 40 of a full-term pregnancy. This timespan includes the second and third trimesters of pregnancy. Steady weight gain during this time is especially important if you start out at a healthy weight or you're underweight. According to the pregnancy guidelines, you should try to gain about 1 pound (0.5 kilogram) a week until delivery. An extra 300 calories a day might be enough to help you meet this goal. You can get around 300 calories from a sandwich and a glass of skim milk.

For people who are overweight or obese, the guidelines suggest a weight gain of about 1/2 pound (0.2 kilogram) a week in the second and third trimesters. Try adding a glass of low-fat milk or an ounce of cheese and a serving of fresh fruit to your diet.

Your healthcare professional keeps a close eye on your weight during pregnancy. You can do your part by eating a nutritious diet. Most pregnant people also should aim to get at least 30 minutes of moderate-intensity exercise on most days. This type of exercise includes activities such as brisk walking and swimming. It is safe to continue a longer or more intense exercise routine if you followed one before you became pregnant. But talk with your healthcare professional before you start a new exercise program.

Also, be sure to go to all of your prenatal healthcare checkups while you're pregnant. To keep your pregnancy weight gain on target, your healthcare professional may suggest ways to boost calories or cut back as needed.

If you're carrying twins or other multiples, you'll likely need to gain more weight. Again, work with your health care provider to determine what's right for you.

Consider these general guidelines for pregnancy weight gain if you're carrying twins:

Your health care provider will keep a close eye on your weight. You can do your part by eating a healthy diet. Also, for most pregnant women, getting at least 30 minutes of moderate-intensity exercise, such as brisk walking or swimming, is recommended on most days. However, talk to your health care provider before starting an exercise program. And be sure to keep your prenatal appointments. To keep your pregnancy weight gain on target, your health care provider might offer suggestions for boosting calories or scaling back as needed.