Our Baby Journey16 weeks pregnant
16 weeks pregnant is about 3½ months. It falls in the fourth month of pregnancy. You are in week 16 of 40, in the second trimester. Here is what is happening with your baby and your body this week.
Your baby is about the size of an avocado.
Length: about 11.6 cm (4.6 in) from crown to rump · Weight: about 100 g (3.5 oz)
Your baby at 16 weeks
The eyes and ears are moving into their final positions. The baby's heart pumps a lot of blood every day.
Your baby's face continues to change as the eyes settle toward the front and the ears move closer to their final position on the sides of the head. The eyes can make slow side-to-side movements beneath the closed eyelids, and the facial muscles allow a wider range of expressions.
The muscles of the back are getting stronger, so the baby can hold the head straighter and stretch out more. The arm and leg movements are becoming more coordinated, and with more room to move, some of these kicks and rolls may now be strong enough for you to notice.
The toenails are starting to grow, and the skin is still thin enough that blood vessels show through. The heart and circulatory system are working hard to supply the fast-growing body, and the umbilical cord is carrying nutrients and oxygen from the placenta.
Your body at 16 weeks
Some people start to feel the first gentle movements, often described as flutters.
Quickening, the first time you feel your baby move, often happens between 16 and 25 weeks. People who have been pregnant before tend to recognize it earlier, while in a first pregnancy it is often closer to 20 weeks. Early movements can feel like bubbles, fluttering, or a light tapping, and are easy to mistake for gas. Your growing blood volume may give your skin a healthy glow, but extra oil can also cause breakouts. Ongoing constipation and backache are common as your uterus grows.
Your belly at week 16
In month 4 (weeks 14–17) your lower belly starts to round out. In a first pregnancy many people start to show around 16 weeks or a little later. At about 16 weeks the top of the uterus sits roughly halfway between your pubic bone and your belly button.
Belly size and shape vary a lot depending on your build, whether this is your first pregnancy, your baby's position and the amount of amniotic fluid. At checkups your doctor or midwife may measure your fundal height to track your baby's growth, and may arrange an ultrasound if the measurement is quite different from what they expect.
Symptoms at 16 weeks pregnant
- Possible first flutters of movement
- Skin glow or breakouts
- Backache
- Constipation
- Stuffy nose
- Increased appetite
Checkups around week 16
Many providers schedule a routine prenatal visit around 16 weeks to check your blood pressure and urine, review any screening results, and listen to the baby's heartbeat. If you are having second-trimester blood screening, it is often done around now. Timing varies by country and clinic.
Tips for week 16
- Wear comfortable, loose-fitting clothes.
- Keep healthy snacks with you.
- Don't worry if you can't feel movement yet — it's common to feel it later in a first pregnancy.
Common symptoms in the second trimester
The second trimester runs from week 14 to week 27. Nausea often eases, energy returns, your bump starts to show, and you will begin to feel your baby move. Not everyone has every symptom, and it is normal for symptoms to come and go. Common ones include:
- A growing bump and weight gain
- First baby movements, usually felt between weeks 16 and 25
- Round ligament pain (sharp pains low in the belly or groin)
- Heartburn and indigestion
- Back ache
- A blocked nose or nosebleeds
- Leg cramps
- Skin changes such as a dark line on the belly or darker patches on the face
Read the full second trimester guide.
When to call your doctor or midwife
Contact your healthcare provider or maternity unit straight away, or get emergency care, if you have:
- Vaginal bleeding
- Severe or persistent abdominal pain or cramping
- A severe headache, blurred vision, or sudden swelling of your face, hands or feet
- A fever of 38°C (100.4°F) or higher
- Fluid leaking from your vagina
- Severe vomiting where you cannot keep fluids down
- Your baby moving less than usual or a change in their pattern of movements (later in pregnancy)
- Regular contractions before 37 weeks
- Pain or burning when you urinate
- Feeling very low, anxious, or having thoughts of harming yourself
Have a question about week 16?
Ask our AI pregnancy assistant about symptoms, nutrition, scans or anything else on your mind this week.
Frequently asked questions
How big is my baby at 16 weeks pregnant?
At 16 weeks pregnant, your baby is about the size of an avocado. That is about 11.6 cm (4.6 in) from crown to rump, weighing about 100 g (3.5 oz).
How big is my belly at week 16 of pregnancy?
In month 4 (weeks 14–17) your lower belly starts to round out. In a first pregnancy many people start to show around 16 weeks or a little later. At about 16 weeks the top of the uterus sits roughly halfway between your pubic bone and your belly button. Bump size, shape and when you start to show vary a lot from person to person.
What does baby movement feel like at 16 weeks?
Early movements are usually very subtle. People describe them as fluttering, bubbles popping, a gentle swish, or a light tap, and they can easily be mistaken for gas or tummy rumbling. You are most likely to notice them when you are lying still and relaxed. At first they come and go, and you won't feel them every day.
Why can't I feel my baby move at 16 weeks?
This is very common, especially in a first pregnancy, when movements are often felt closer to 20 weeks or later. Your baby is still small and well cushioned by amniotic fluid. If your placenta is at the front of your uterus (an anterior placenta), it can also muffle early movements. If you haven't felt any movement by around 24 weeks, talk to your doctor or midwife.
Is acne normal in the second trimester?
Yes. Hormone changes can increase oil production and lead to breakouts, even if you rarely had acne before. Washing gently twice a day and using oil-free, non-comedogenic products can help. Some acne treatments, including oral isotretinoin and some topical retinoids, should be avoided in pregnancy, so check with your doctor, midwife, or pharmacist before using medicated products.
What trimester is 16 weeks pregnant?
Week 16 is in the second trimester, which covers weeks 14 to 27.
How many months is 16 weeks pregnant?
16 weeks pregnant is about 3½ months. It falls in the fourth month of pregnancy. The fourth month covers weeks 14 to 17. Pregnancy is about 40 weeks, or roughly 9 months, counted from the first day of your last period.
This page is general educational information and is not a substitute for advice from your doctor or midwife. Every pregnancy is different, and baby sizes are approximate averages. Last updated 2026-11-07. See our medical disclaimer.