Week 16 Pregnancy: Ultrasound, Belly Bump & Symptoms

Week 16 Pregnancy Ultrasound Belly Bump and Symptoms

Can you believe you’re in week 16 of your pregnancy already? Let’s look at what’s going on this week, including baby’s growth and development, your belly and weight gain, ultrasounds and tests, and yet another round of symptoms!

Estimated reading time: 10 minutes

Week 16 Pregnancy: How Big is Baby?

In the 14 weeks since your baby was conceived, he has grown to about the size of an avocado. Baby is around 4 1/2 inches from crown to rump, and weighs about 2 3/4 ounces (1). Other developments include:

Check out baby’s developmental milestones at week 16 pregnancy!
  • Fine hair called lanugo now covers baby’s body and head.
  • Fingernails are well formed.
  • Eyes don’t open, but they do move.
  • Tiny bones in the ear are formed and in place, so baby may be able to hear already!

Week 16 Pregnancy: Pregnant Belly Bump and Weight

Weight Gain

We’ve talked a lot about how big your bump might be now, and what’s going on inside, but let’s talk about weight gain. In the first trimester, some women don’t gain, or they may even lose weight due to morning sickness. Most people have a better appetite in the second trimester, so you may need to watch what you eat more carefully. To ensure that your weight gain is controlled and that your baby gets all the necessary nutrients, it’s best to stick to a healthy diet throughout your pregnancy.

Check out this cute 16 week pregnancy belly bump!

A typical, healthy weight gain in the first trimester is about five pounds. In the second trimester, you may gain up to a pound a week. Both of these numbers assume that you started your pregnancy at a normal weight.

How Much Weight Should I Gain During Pregnancy?

How much you should gain overall during pregnancy actually depends on your pre-pregnancy weight. Here’s a general overview. You should, of course, discuss your specifics with your healthcare provider.

  • Underweight before pregnancy – should gain 28 – 40 pounds
  • Normal weight before pregnancy – should gain 25 – 35 pounds
  • Overweight before pregnancy – should gain 15 – 25 pounds
  • Obese before pregnancy – should gain 11 – 20 pounds (1, 2)

Week 16 Pregnancy: Ultrasound and other Screening Tests

You may have a visit scheduled sometime in the 16 to 18 week window, and this is the time frame where some additional screenings may be done. Most tests are optional, so do your research and talk to your provider about which tests are necessary or best for you and your baby.


How Do Ultrasounds Work?

Ultrasounds use sound waves to “see” inside your uterus and assess your baby. The equipment picks up echoes of sound waves which indicate differences in tissue density. These echoes are then converted into a video image. If you know what you’re looking for, you can see baby’s skeleton and organs, amniotic fluid, umbilical cord, placenta, and the uterus. (3)

16-18 Week Ultrasounds to Assess Baby’s Health

While many expectant parents look forward to ultrasounds to sneak a peek of their little ones, or in hopes of determining gender, ultrasound is actually a very valuable medical tool. It helps your provider determine whether your baby appears to be healthy and developing normally. An ultrasound may be ordered:

  • to diagnose a multiple pregnancy
  • to aid in amniocentesis
  • due to bleeding related to placenta previa or placental abruption
  • concerns of intrauterine-growth restriction (IUGR)
  • to determine if the placenta has attached normally and is healthy
  • or simply as a matter of routine screening.
You’ll typically have an ultrasound between week 16 – 18 to do a full scan of baby’s body and organs.

Are Ultrasounds Safe?

Studies have shown ultrasound to be safe for both mom and baby. You can find a great deal of in-depth information about ultrasound on the March of Dimes website. However, out of caution, it’s best to only do ultrasounds when they’re medically necessary. Many doctors discourage boutique ultrasounds done exclusively to find out baby’s gender or to get a better peek at your little one in 3D.

Finding Out Baby’s Gender

Can You Tell The Sex of the Baby at 16 Weeks?

If you have an ultrasound scheduled at 16 weeks, it’s possible that your doctor may be able to tell whether you’ve got a He or a She on the way. The accuracy of determining baby’s gender through an ultrasound increases as baby ages. However, you may find it exciting to know that studies have found gender ultrasounds to be 98% accurate at determining gender as early as even week 12 pregnancy (5).

What Does a Boy Ultrasound Look Like?

It’s often difficult for a parent to know what organs they’re looking during their baby’s ultrasound. However, the “boy parts” are usually pretty easy to recognize, as you’ll see in the pictures below.

It’s a boy!
Yep. Definitely a boy.

What Does a Girl Ultrasound Look Like?

Girl ultrasounds, on the other hand, can be a bit more tricky to distinguish. Check out these girl ultrasound pictures below:

It’s a GIRL!!! But it may require a well-trained ultrasound tech to help point it out to you!
This ultrasound picture of a baby girl was taken at around 17 weeks.
It’s often easier to recognize the “lady parts” once baby is a bit older. This ultrasound picture was taken at around 35 weeks.

Other Screening Tests

There are several types of optional screening tests you may be offered early in your second trimester. These tests look for things like genetic disorders and neural tube defects. It can be helpful to learn if these conditions exist as early as possible. In some cases, treatment can begin before baby is born. Early detection can also give parents time to prepare for a child with special healthcare needs.

These are not diagnostic tests, meaning that they don’t diagnose any problem; they are screening tests to screen for possible problems. If any of the tests come back suggesting that there may be a problem, further tests are done to confirm that diagnosis.

Triple Screen Test

What is a Triple Screen Test

A triple-screen is a blood test that checks your levels of alpha-fetoprotein, human chorionic gonadotripin, and unconjugated estriol (1). Those are big words, but basically the tests measure the amounts of these substances in your blood. Comparing the amounts present versus the amounts that are expected at your gestation, age, health, etc. can help determine if there may be a problem that warrants further testing.

Beware False Positives

It is important to know that this test has a higher level of false positives than some other tests. This means that a test may say there could be a problem when there really isn’t. False positives can have many simple causes, such as an inaccurate due date. For example, if you believe you’re 18 weeks pregnant but you’re in fact only 16 weeks pregnant, the test may show that your numbers are low. Keep this high incidence of false positives in mind if your triple-screen indicates the possibility of a problem.

Quad-Screen Test

A quad-screen test is the same as the triple-screen except that they add a fourth measurement. This test also checks your inhibin-A level. This test is most effective at detecting Down syndrome and has a lower false-positive rate than the triple-screen test. (1)

Week 16 Pregnancy: Symptoms

Let’s take a look at a couple more symptoms you may be experiencing, or may find yourself dealing with as your pregnancy progresses.

Spider Veins

You may notice that you can see tiny red veins under the skin, especially on your legs or face. During pregnancy, the volume of blood in your body increases, which is a strain on your veins. Increased hormones like progesterone encourages the walls of your veins to relax. This, in turn, can cause the veins to bulge out and twist, resulting in spider veins.

Spider veins are tiny, red, swollen veins that twist and turn. They usually fade shortly after baby is born.

Although you might not like the look of them, spider veins aren’t anything to worry about. They are a normal part of the circulation changes of pregnancy, and usually fade once your baby is born (2).


In plain terms, flatulence is the passing of gas. Pregnancy causes your intestines to be a bit sluggish. And pressure on the intestines from the growing uterus leads to delayed emptying of the bowels. Combined, you have the perfect recipe for increased gas 🙂 (4).

Can flatulence be avoided? Well, you can try steering clear of the types of foods that are more likely to cause gas, such as beans, cabbage, and broccoli. However, most of these foods are healthy and can play an important part of a balanced pregnancy diet. When it comes to gas, your best bet may be to chalk it up to the adventure that is pregnancy, and keep your sense of humor.

Join us next week to check out what’s happening in pregnancy week 17.

Kopa Birth’s online childbirth classes allow you to prepare for a natural childbirth from the comfort of your own home, 24/7. Enroll today in our free online childbirth class to learn more about preparing for a natural hospital birth.


  1. Glade, B.C., Schuler, J.  (2011).  Your Pregnancy Week by Week, 7th edition.  First Da Capo Press
  2. The American College of Obstetricians and Gynecologists.  (2010).  Your Pregnancy and Childbirth Month to Month, 5th edition.
  3. Simkin, P. (2010). Pregnancy, Childbirth and the Newborn, 4th edition. Meadowbrook Press
  4. Ladewig, P.A., London, M.L., Davidson, M.R.  (2006).  Contemporary Maternal-Newborn Nursing Care, 6th edition.  Pearson Prentice Hall.  Upper Saddle River, NJ.
  5. Efrat, Z., Akinfenwa, O.O., Nicolaides, K.H. (1999). First-trimester determination of fetal gender by ultrasound. Ultrasound Obstet Gynecol.

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Meet Katie Griffin

I’m a registered nurse, Lamaze certified childbirth educator, and the mother of 7. I help women realize their dream of a natural, intimate, and empowering hospital birth.

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Can you believe you’re in week 16 of your pregnancy already? Let’s look at what’s going on this week, including baby’s growth and development, your belly and weight gain, ultrasounds