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16 Weeks Pregnant: Week by Week Pregnancy

Symptoms, Tips and Fetal Development


It’s the second trimester and you’re probably feeling fine, without too many unpleasant (or at least not unbearable) symptoms. Your baby is logging steady growth, looks just like a miniature doll, and will soon begin making his or her presence known through flutters and kicks. Here’s what you can expect at 16 weeks pregnant, including what new pregnancy symptoms you might be experiencing.

Baby at 16 weeks pregnant

Your baby’s stats this week: measuring 4-4.5 inches crown to rump, and tipping the scales at 3-4 ounces. S/he can smile, though she won't be doing it on purpose for quite a while, and s/he’s practicing making regular breathing movements. Your baby can also swallow, yawn, and even hiccup, though you won't feel those hiccups for a few more weeks. All of these actions help develop the entire digestive system. 

Fully-developed legs, arms, and joints enable your baby to make all range of motions (including sucking his or her thumb). Any day now you may start to feel tiny flutters of movement, sometimes called quickening, especially if your placenta is located toward the back. The placenta helps cushion the movements, plus your baby is only active for up to five minutes at a time. If you haven't felt those special baby flutters yet, just wait – you will soon!

Your body at 16 weeks pregnant

Not so easy hiding that belly anymore: Your uterus has picked up almost four ounces of weight in the last six weeks and can be felt three inches below the belly button. It currently contains about 7.5 ounces of amniotic fluid.

Chances are good that you're feeling hungrier than normal now. If the munchies are taking over, make sure you're eating healthy snacks that are packed with nutrients and amino acids, such as cheese, eggs, and milk. For reasons doctors don’t yet understand, a small percentage of women may continue to experience morning sickness. Your levels of the pregnancy hormone HCG have dropped significantly, although estrogen and progesterone remain on the rise. Ask your care provider if you’re still feeling sick at 16 weeks pregnant.

pregnancy week 16 embryo
Weekly development of a human fetus at 16 weeks pregnant.

Your breasts may continue to swell and some moms find that they're already leaking colostrum, especially if they've nursed a baby before. Colostrum is a special pre-milk that's full of nutrients to sustain your baby before your actual milk comes in.

16 weeks pregnant ultrasound/screening

Your doctor might recommend undergoing the so-called triple screen to check your levels of alpha-fetoprotein (AFP, see Pregnancy Checklist, below), HCG, and unconjugated estriol, which is estrogen produced by the placenta. Abnormal results from this blood draw could indicate chromosomal abnormalities in your baby, but these screenings also have high incidences of false positives. The quad screen tests the levels of an additional hormone called inhibin, and is performed between pregnancy weeks 15-18.

How big is my baby at 16 weeks?

an avocado sliced in half sitting on a wooden board, full of healthy fats that are ideal for nourishing breastfeeding moms

At 16 weeks pregnant, your baby is the size of an avocado, on average measuring at 4.3 inches long and weighing on average at 4.5 ounces.

16 weeks is how many months pregnant? 

At this stage in your pregnancy, you're four months, zero weeks (4m0w) months pregnant. 

Common symptoms at 16 weeks pregnant

These are some pregnancy symptoms commonly experienced by women at 16 weeks.

  • Making balance adjustments: Your uterus is now positioned higher and more forward, shifting your center of gravity and causing you to unconsciously adjust your posture and the way you walk and stand. It’s possible your belly button has started to stick out a bit!
  • Skin pigmentation: Whether it’s a linea nigra on your belly, darkening areolas around your nipples, shading in your armpits and inner thighs, or melasma (aka chloasma, the mask of pregnancy) on your face, skin pigmentation is a common side effect of pregnancy. All will fade and most will completely disappear after pregnancy.
  • Feeling excited and apprehensive: The more real the pregnancy becomes, the more excited and/or nervous you may be feeling about this baby.
  • Canker sores: Those pesky mouth sores are more common when you’re pregnant, joining other potential symptoms like bleeding gums, gingivitis, and tooth decay in your pregnancy mouth.
  • Insomnia: Sleeplessness is a common issue for women during pregnancy, who may find themselves lying awake with racing thoughts around becoming a mother; difficulties finding a comfy sleeping position; or unable to get back to sleep after waking up to go to the bathroom.  
  • Round ligament pain: Those abdomen aches and pains aren’t going anywhere as your ligaments continue stretching to accommodate your growing uterus. Some of those pains are also your internal organs protesting as the uterus encroaches on their space.
  • Fetal movement: Some women feel flutters of baby movement at 16 weeks, although it’s still pretty early. It’s more common to feel them beginning between weeks 18-22.
  • Urinary Tract Infections (UTI): Some women are prone to UTIs in pregnancy. Watch for symptoms like burning while peeing, fever, feeling a frequent need to urinate, abdominal pain, and backache, and contact to your care providers. Untreated UTIs can cause preterm labor.
  • Increased vaginal discharge
  • Back pain: Lower back pain in pregnancy is common, caused by loosening ligaments and the curving of your spine to compensate for your shifting center of gravity.

Pregnancy checklist at 16 weeks pregnant

Here are three things you might consider tackling when you’re 16 weeks pregnant.

  • Change your sleeping position: Bad news, back sleepers. With that ever-increasing belly, it’s no longer a smart idea to lie flat on your back. Reclining or sleeping propped up is ok, but lying flat can put pressure on the major blood vessels the aorta and the vena cava and lead to reduced blood flow to your baby. Try these sleep position tips, or aim to sleep on your left side (the vena cava runs down the right side of the body).
  • Get some comfy shoes: Feet can grow as much as a half size in pregnancy. Add pregnancy swelling to that and you might be feeling like investing in some comfy shoes. It’s a good idea to hit the shoe store at the end of the day or evening when your feet are the most swollen and you’ll get the best fit.
  • Knowledge check: The Alpha-Fetoprotein (AFP) test: Required in some states and recommended only to at-risk mothers in others, the AFP screen checks to see if your baby’s liver is producing abnormal levels of the protein AFP. A low level could be a sign of Down Syndrome and mean more testing is recommended. The AFP screen is offered as part of the triple or quad screen.

What to Expect at 17 Weeks Pregnant

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