Skip to main content
First trimester weeks

Congrats! During the first trimester, you’re getting used to the idea of being pregnant.

Second trimester weeks

As you enter this second trimester, your body will settle down to pregnancy.

Third trimester weeks

You've reached the third and final trimester and will be heavily pregnant by now.

Week 18 of Pregnancy

You'll find you're gaining weight week by week, which is perfectly normal.
Not all the weight you're gaining is your baby. In fact, most of the increase is because parts of your body, such as your breasts, are getting bigger and your blood volume is increasing. You might want to think about signing up for prenatal classes now because they fill up quickly. They are a great source of information, as well as a good way to make friends and compare notes with other pregnant women.

17 Weeks, 3 Days

158 days to go...

ultrasound of human fetus at 17 weeks and 3 days

Your baby today

Because 2D ultrasound only shows a "slice" of the baby, parts may appear to be missing, such as the arm here which stops midway.

It's normal and healthy for you to gain more weight in the second trimester than in the early months of pregnancy.

While you may have gained little weight in the first trimester, from the second trimester onward you will gain weight each week. On average, women should put on 3-4 pounds per month from the second trimester to the end of pregnancy, though the weight gain tends to slow down in the last few weeks. The amount of weight you should be gaining depends on many factors, not least your starting Body Mass Index (BMI). The target weight gains are detailed below.

Not all of the weight gained is the baby; in fact, the fetus makes up only a small part. The rest of the weight is accounted for by your growing uterus, amniotic fluid, breasts, and increased blood volume and fat (see How much weight will you gain?).

If you have any concerns about your weight, seek advice from your doctor. Your weight may not be checked routinely at your prenatal checkups, but your doctor will weigh you if she's concerned about the amount of weight you're gaining.

Weight gain

Your target weight gain for the second trimester (as well as the third trimester) is 9-16 pounds, which is considerably more than that the recommended 2-4 pounds for the first trimester. If, due to pregnancy discomforts, such as morning sickness, you had a difficult first trimester and did not gain much weight, this is a good time to increase your calories to try to make up some of the weight gain. If you gained too much weight in the first trimester, focus on staying active, and filling your plate with lower-calorie yet nutrient-rich fruits and vegetables.

Keep your target goal weight gain in mind. The recommended total pregnancy weight gain is 25-35 pounds for women whose Body Mass Index (BMI) is in the normal range, between 20 and 25.

If you were overweight at the start of pregnancy, your recommended weight gain is 15-25 pounds. Obese women should gain at least 15 pounds. If you started underweight, the recommended weight gain is 28-40 pounds. If you're expecting twins, you should aim for a total gain of about 35-45 pounds.

Ask A... Doctor

I keep having hot flashes. Is this normal?

Many women experience hot flushes during pregnancy as a result of increased levels of the hormone estrogen. This encourages the blood vessels to dilate-suffusing them with blood, and heat. What's more, when you're pregnant, your metabolism increases, causing extra heat to be produced. That's not to mention the little heater that you have growing inside you.

Wear layers that can be speedily removed and avoid eating spicy foods, and drinking alcohol and caffeine, all of which can encourage hot flashes. Exercise can help by improving circulation, and yoga, and other relaxation exercises, can help you to keep cool and calm.

17 Weeks, 3 Days

158 days to go...

Join the Family

Your partner in parenting from baby name inspiration to college planning.