16 weeks pregnant: baby, body and what to expect

Trimester 2 of 3About 3.5 months24 weeks to go

Week 16 of pregnancy: baby is about the size of a avocado

Week 16 at a glance

At 16 weeks, the fetus is often about 11–12 cm (4.3–4.7 in) long, roughly the size of an avocado. The eyes are moving toward their usual place on the face, and the nervous system may start to respond to light, though this is not the same as seeing like a child or adult.

16 weeks pregnant is about 3.5 months. You are in month 4 of pregnancy and the second trimester.

Your baby at 16 weeks

Eyes Move Into Place and May Begin Responding to Light

At 16 weeks, the eyes are moving into a more typical position on the face, and the nervous system may begin to respond to light.

What is happening this week

The fetus is often about 11–12 cm (4.3–4.7 in) long. The face is becoming more recognizable as the eyes move closer to their usual place, and movements are becoming stronger and more coordinated.

The eyes are gradually shifting toward the front of the face.
The retina and nerve pathways are maturing, so a response to bright light may be possible.
Nails, muscles and bones continue developing, and movements may become more coordinated.

An ultrasound at this stage may show active movements and facial expressions. If they are not seen during one scan, this is often due to the baby's position or image quality and is usually not a concern.

How this week may feel

For many pregnant people, nausea starts to ease by 16 weeks and energy may begin to improve. Fatigue, heartburn or sensitivity to smells can continue for some.

Call your OB-GYN or midwife right away if you have bleeding, severe pain, fever, fainting, or a sudden worsening in how you feel.

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Your body at 16 weeks

What Is Normal?

Your weight is changing

At 16 weeks, many pregnant people find their appetite improves as first-trimester nausea fades. Your body also begins storing more energy and nutrients to support your baby's growth.

What are the benchmarks?

Many providers use a general guide of about 1 pound (roughly 0.5 kg) per week during the second and third trimesters for people who started at a healthy pre-pregnancy weight. Recommended totals vary based on your pre-pregnancy body mass index (BMI), so your provider may suggest a different range for you. These numbers are only averages, and your own pattern can differ.

Your pre-pregnancy BMI (body mass index).
Your individual metabolism.
Your overall well-being and nutrition.

Weight gain during pregnancy includes more than the baby. It also covers increased blood volume, amniotic fluid, the placenta, breast tissue, and stored energy for breastfeeding.

When should you contact your provider?

Contact your healthcare provider right away if you notice sudden weight gain over a few days, especially with swelling in your face or hands, severe headache, vision changes, or belly pain. These can be signs of preeclampsia, which needs prompt care. Also tell your provider if you have steady weight loss over several weeks or cannot keep food or fluids down.

Common symptoms at 16 weeks

Round ligament twinges

Sharp or pulling pain in the lower belly or groin can happen as the muscles supporting the uterus stretch. Slow position changes, warm baths, and a supportive belt may ease it, but tell your provider if pain is severe or steady.

Stuffy nose or nosebleeds

Extra blood flow can swell the lining of the nose, which may cause congestion or light nosebleeds. A saline spray or a cool-mist humidifier may help, and your provider can suggest what is safe to use.

Dizziness when standing up

Blood pressure can run lower during pregnancy, so you may feel lightheaded after standing quickly. Getting up slowly and staying hydrated can help, and let your provider know if you faint.

Increased appetite

Hunger often grows as the body needs more energy and nutrients. Regular meals and snacks with protein and fiber can keep energy steadier through the day.

Skin changes

A darker line down the belly or patches of darker skin on the face are common and often fade after birth. Sunscreen can help keep these areas from getting darker.

Mild tiredness

Many people notice energy starting to improve in the second trimester. Short rest breaks and gentle activity, like walking, can help you feel more like yourself.

Your week 16 checklist

Write down your current weight and date so you can track your trend over time. Ask your provider which weight goal fits your body and pregnancy. Include iron-rich foods like beans, lean meat, or fortified cereal in your meals. Drink water throughout the day, and keep a bottle nearby. Ask about screening options offered between 15 and 22 weeks and what your insurance covers. Save your provider's after-hours number and know the warning signs that mean you should call right away.

Tests and appointments

Quad screen (optional blood test). This blood test may be offered between about 15 and 22 weeks to estimate the chance of certain chromosome conditions and neural tube defects. It is a screening test, so it does not give a final diagnosis.

For your partner: Ask how you can help with meals, rides to appointments, or household tasks this week. Listening to questions and coming to visits, if possible, can help you both feel more prepared.

Questions about week 16

How many months is 16 weeks pregnant?

16 weeks pregnant is about 3.5 months. You are in month 4 of pregnancy and the second trimester.

What trimester is 16 weeks?

Week 16 is in the second trimester. The first trimester runs through week 13, the second from week 14 to 27 and the third from week 28 until birth.

What is happening with the baby at 16 weeks?

At 16 weeks, the fetus is often about 11–12 cm (4.3–4.7 in) long, roughly the size of an avocado. The eyes are moving toward their usual place on the face, and the nervous system may start to respond to light, though this is not the same as seeing like a child or adult.

Is it normal to feel dizzy at 16 weeks?

Some dizziness is common because blood vessels widen and blood pressure may dip. Stand up slowly, sip water, and avoid long periods without food. Tell your provider if dizziness is frequent, or if you faint, have chest pain, or see blurred vision.

Can the baby hear or see yet?

At 16 weeks, the baby's ears are forming and the eyes are moving toward their usual place. Hearing and light response are developing, but the baby cannot see like a child or adult yet.

Why do I have a nosebleed during pregnancy?

Increased blood flow and swelling in the nose lining can make it bleed more easily. A saline spray or humidifier may help. Call your provider if bleeding is heavy or does not stop after about 15 minutes of gentle pressure.

Safe or not?

Ask your doctorCan you drink kombucha while pregnant?Generally OKCan you fly while pregnant?Generally OKCan I eat avocado while pregnant?Generally OKCan I eat shrimp while pregnant?

Guides for this stage

Mental healthFeeling Less Attractive in Pregnancy: Learning to Accept a Changing Body Medical careCervical length check in pregnancy: what the test shows HealthManaging chronic conditions during pregnancy FeedingColostrum Leaking in the Second Trimester: What's Normal and What to Do

Coming up next weekWeek 17: Your Baby's Skeleton Begins to HardenRead week 17 →

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Learn more

NIH: Pregnancy (NICHD)
CDC: Pregnancy

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General information only; it does not replace advice from your doctor or midwife.