Pregnancy Week by Week – Weeks 17 to 20

Learn what to expect week by week as you approach the halfway mark in your pregnancy.

By week 20, you’ll be at the halfway point in your pregnancy. You might be amazed at how quickly the time has flown, or wish your baby’s birthday would hurry up and get here already! Either way, take time to enjoy the relative quiet (if this is your first child) of these next few months, and prepare for your baby’s arrival.

Here’s a look at what’s happening with your baby – and your body – this month.

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Weeks 17 - 18

Your baby has doubled in size over the past couple of weeks. His facial features are filling in, and organs like the lungs and kidneys are starting to do their respective jobs. To make sure your baby is growing and developing normally, you’ll see your doctor for prenatal visits about every four weeks during this trimester.

Your body

When you stand up too quickly, do you notice that you feel a little dizzy? As pregnancy hormones act on your cardiovascular system, you can develop low blood pressure. Try to get up more slowly from a seated or lying position to avoid the spinning feeling.

You might also have noticed a white substance on your underwear when you use the bathroom. This discharge is called leukorrhea, and it’s perfectly normal. But if the discharge develops a strong smell or turns green or yellow, it could be a sign that you have a yeast infection. See your doctor to have it checked out.

Your baby

Your baby now weighs more than 5 ounces – about the weight of a deck of cards – and measures more than 5 inches long. Inside her still-tiny frame, her bones are starting to solidify. They’ll form the scaffolding that will keep her upright throughout her life. Her face and body are filling out, thanks to fat tissue that’s building up under the skin. Baby’s umbilical cord — the lifeline that delivers oxygen and nutrients from your body to hers — is thickening and lengthening now to support her growth.

Baby’s sensory organs continue to develop. She has eyes that can move (though still behind closed lids) and ears that can hear. Not long from now, when you turn on your favorite music, you may feel baby fluttering along to the rhythm!

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Weeks 19 - 20

It’s about the time for your second ultrasound, which will let your doctor see how your baby is growing, confirm your due date, and check for any problems. If you’d like to learn your baby’s gender, now might be the time. The sex organs are formed now. A boy’s genitals should be visible. Girls have a complete uterus and fallopian tubes. Your doctor will also give you a blood test (if you haven’t had it already) called the triple screen or quad screen to check for Down syndrome and neural tube birth defects.

Your body

You may have recently discovered a dark line running down the center of your belly, straight through your bellybutton. Called the linea nigra, this line was likely there before you got pregnant, but it was too pale to see. Changing levels of pregnancy hormones cause the darkening pigmentation. If you’re worried about ever being able to wear a bikini again, don’t fear – the line should disappear after your baby is born.

Your baby

By now, you’ve likely felt a few little flutters inside your uterus. At first, these movements will be hard to distinguish from gas or indigestion. But eventually, the flutters will turn into strong kicks. In a couple of months, you might even see an elbow or foot poking up through the skin of your belly!

At this point in your pregnancy, your baby’s skin is covered in a waxy white substance called vernix. Made up of oil and shed skin cells, this coating protects baby’s skin while he soaks in amniotic fluid.

What to remember

Although you might feel more worn out than usual, sleep can be harder to come by at this point in your pregnancy. If your growing belly doesn’t keep you awake, the multiple nighttime bathroom visits surely will. Take naps during the day to make up for lost slumber. Try sleeping on your side pressed against a body pillow. Not only is side sleeping better for your blood flow than back sleeping, but it’s also more comfortable.

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