How many months is 16 weeks pregnant?

16 weeks pregnant puts you in month 4 of pregnancy. Month 4 covers weeks 14 to 17. Providers count in weeks; months are approximate.

How big is the baby at 16 weeks?

At 16 weeks, the baby is about the size of a avocado, roughly 11.6 cm long and around 100 g. That is an average; healthy babies vary.

Can I feel kicks at 16 weeks?

Maybe. First movements, called quickening, usually start between 16 and 20 weeks. If you've been pregnant before, you may notice them by about 16 weeks. In a first pregnancy it's common not to feel anything until about 20 weeks. Early movements are soft, like fluttering, bubbles popping or tiny taps, and are easy to mistake for gas. Kicks that someone else can feel from the outside come later.

How do I know my baby is OK at 16 weeks pregnant?

Before you feel regular movements, the main checks are your prenatal visits, where the heartbeat is usually checked with a Doppler, and the anatomy scan at 18 to 22 weeks. How you feel day to day isn't a reliable guide on its own. Call your provider if you have bleeding, fluid leaking from the vagina, strong or regular cramps, or a fever.

Can I sleep on my back at 16 weeks pregnant?

Yes, for now. The advice to go to sleep on your side applies from 28 weeks. Research found that going to sleep on your back after 28 weeks is linked to about twice the risk of stillbirth, probably because the weight of the womb presses on major blood vessels. Before then, sleep in whatever position is comfortable. Many people start practising side-sleeping in the second trimester so it feels natural later.

Are there symptoms of a boy or girl at 16 weeks?

No symptom reliably predicts the baby's sex, including bump shape, cravings, skin changes and heart rate. When researchers tested the heart-rate idea in 477 pregnancies, boys and girls had almost the same rate. If you want to know, the anatomy scan at 18 to 22 weeks can usually show the sex, and cell-free DNA screening, if you had it, may already have reported it.

Why do I get sharp pains in my side at 16 weeks?

Brief, sharp pains on one or both sides of the lower belly or groin are common from the second trimester. They're called round ligament pains and come from the ligaments that support your growing womb as they stretch. They often happen when you stand up quickly, cough or roll over. Moving more slowly and resting can help. Pain that keeps coming back in waves, gets stronger, or comes with bleeding or fluid needs a call to your provider.

16 Weeks Pregnant

At 16 weeks pregnant, you're in month 4 and well into the second trimester. Your baby is about 11.6 cm long from head to bottom, around the size of an avocado, and can now move its arms and legs, make fists and pull faces, though only at random for now. Many people feel better this month: morning sickness usually clears up by weeks 16 to 20, and energy often comes back. The bump is starting to show, often low down. This page covers what a 16-week bump looks like, whether you can feel kicks yet, how to know the baby is OK between checkups, and whether it's fine to sleep on your back.

What trimester is 16 weeks?

Week 16 is in the second trimester, which runs from week 13 to week 27 (NHS). It is week 4 of 15 in this trimester, and the third trimester starts at week 28.

Week 16 — second trimester, month 4; 24 weeks to go until your due date.
Baby's size — about a avocado, ~11.6 cm.

Not sure it's 16 weeks? Try our due date calculator.

How big is your baby at 16 weeks?

Size of a

avocado

Length, head to bottom

~11.6 cm

Weight

~100 g

Up from a apple last week to a avocado now.

Baby development at week 16

The fetus can now make small, coordinated movements: the arms and legs move, the hands can form fists, and the muscles of the back are strong enough to straighten the head and neck. The face is busy too — your baby is starting to pull faces, though any frown or smile is random for now, with no muscle control yet. About the size of an avocado.

What an ultrasound shows at 16 weeks

There's usually no routine scan at 16 weeks. The next one is the detailed anatomy scan at about 18 to 22 weeks. If you do have a scan now, for example a follow-up or private scan, it can show the whole body, including the spine, arms and legs, and often a lot of movement. The sex can sometimes be seen, but it is far more reliable at the anatomy scan.

At checkups around now, the heartbeat is usually checked with a handheld Doppler, and many people hear it for the first time. If you didn't have screening earlier, you may be offered the quad screen: a blood test done between 15 and 22 weeks that screens for Down syndrome, trisomy 18 and neural tube defects.

Your body at 16 weeks

Some begin to feel the first flutters of movement ('quickening')
A rounder, more visible bump
Mild backache
Forgetfulness ('pregnancy brain') for some

Your belly at 16 weeks

By 16 weeks, the top of your uterus sits roughly halfway between your pubic bone and your belly button, and it reaches your belly button at around 20 weeks. That's why a 16-week bump often sits low. First-time parents may only look a little thicker around the middle, while people who have been pregnant before, or are carrying twins, often have a clear bump.

Both are normal. Early on, how big your bump looks depends a lot on your height, build and muscle tone. Your provider starts measuring it to track growth later in pregnancy.

Tips for week 16

First movements may feel like bubbles or flutters — easy to miss early on
Support your back with good posture and supportive shoes
The anatomy scan is usually scheduled for the next few weeks

16 Weeks Pregnant: your questions

What trimester is 16 weeks?: Week 16 is in the second trimester, which runs from week 13 to week 27 (NHS). It is week 4 of 15 in this trimester, and the third trimester starts at week 28.
How many months is 16 weeks pregnant?: 16 weeks pregnant puts you in month 4 of pregnancy. Month 4 covers weeks 14 to 17. Providers count in weeks; months are approximate.
How big is the baby at 16 weeks?: At 16 weeks, the baby is about the size of a avocado, roughly 11.6 cm long and around 100 g. That is an average; healthy babies vary.
Can I feel kicks at 16 weeks?: Maybe. First movements, called quickening, usually start between 16 and 20 weeks. If you've been pregnant before, you may notice them by about 16 weeks. In a first pregnancy it's common not to feel anything until about 20 weeks. Early movements are soft, like fluttering, bubbles popping or tiny taps, and are easy to mistake for gas. Kicks that someone else can feel from the outside come later.
How do I know my baby is OK at 16 weeks pregnant?: Before you feel regular movements, the main checks are your prenatal visits, where the heartbeat is usually checked with a Doppler, and the anatomy scan at 18 to 22 weeks. How you feel day to day isn't a reliable guide on its own. Call your provider if you have bleeding, fluid leaking from the vagina, strong or regular cramps, or a fever.
Can I sleep on my back at 16 weeks pregnant?: Yes, for now. The advice to go to sleep on your side applies from 28 weeks. Research found that going to sleep on your back after 28 weeks is linked to about twice the risk of stillbirth, probably because the weight of the womb presses on major blood vessels. Before then, sleep in whatever position is comfortable. Many people start practising side-sleeping in the second trimester so it feels natural later.
Are there symptoms of a boy or girl at 16 weeks?: No symptom reliably predicts the baby's sex, including bump shape, cravings, skin changes and heart rate. When researchers tested the heart-rate idea in 477 pregnancies, boys and girls had almost the same rate. If you want to know, the anatomy scan at 18 to 22 weeks can usually show the sex, and cell-free DNA screening, if you had it, may already have reported it.
Why do I get sharp pains in my side at 16 weeks?: Brief, sharp pains on one or both sides of the lower belly or groin are common from the second trimester. They're called round ligament pains and come from the ligaments that support your growing womb as they stretch. They often happen when you stand up quickly, cough or roll over. Moving more slowly and resting can help. Pain that keeps coming back in waves, gets stronger, or comes with bleeding or fluid needs a call to your provider.

Useful at week 16

Pregnancy weight gain calculator — your healthy range, week by week
Exercise in pregnancy — what's safe as your energy comes back
Flying while pregnant — the second trimester is often the easiest time to travel
Baby gender predictor — a just-for-fun guess before the anatomy scan
Pregnancy weeks to months — 16 weeks is month 4 — the full chart

← All weeks: the full pregnancy week-by-week guide

Sources

Checked against the following public guidance on October 2, 2026. Advice can differ between countries; your doctor, nurse or midwife can apply it to you.