Our Baby Journey15 weeks pregnant
15 weeks pregnant is about 3½ months. It falls in the fourth month of pregnancy. You are in week 15 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 apple.
Length: about 10.1 cm (4 in) from crown to rump · Weight: about 70 g (2.5 oz)
Your baby at 15 weeks
The skeleton is hardening, and the baby can sense light through closed eyelids.
Your baby's legs are now growing longer than the arms, and all the joints and limbs can move. Bone is gradually replacing the softer cartilage of the skeleton, a process that will continue through pregnancy and childhood. If you had an ultrasound now, the bones would show up clearly.
Although the eyelids are still fused shut, the eyes can detect light, and the baby may move away from a bright light shone on your belly. Taste buds are forming on the tongue, and the scalp hair is starting to develop its pattern.
Your baby is also practicing breathing movements, drawing amniotic fluid in and out of the developing lungs. This doesn't deliver oxygen, which still comes through the placenta and umbilical cord, but it helps the lungs grow and develop for life after birth.
Your body at 15 weeks
You may have a stuffy nose or nosebleeds because of increased blood flow.
Higher levels of estrogen and progesterone, together with increased blood flow, cause the lining of your nose to swell. This can lead to a blocked or runny nose, sometimes called pregnancy rhinitis, along with snoring and the occasional nosebleed. Your gums may also be more sensitive. Your heart is working harder to pump the extra blood around your body, and you may notice that your heart rate is a little faster than usual. Many people find their appetite has fully returned by now, which is a good time to focus on steady, balanced meals.
Your belly at week 15
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 15 weeks pregnant
- Stuffy or runny nose
- Occasional nosebleeds
- Snoring
- Sensitive or bleeding gums
- A slightly faster heart rate
- Heartburn after meals
Checkups around week 15
Second-trimester blood screening (sometimes called the quad or quadruple screen) is often offered between about 15 and 22 weeks, particularly if you didn't have first-trimester screening. If earlier results suggest a higher chance of a chromosomal condition, amniocentesis is usually offered from about 15 weeks. Practices vary by country and clinic.
Tips for week 15
- Use a humidifier or saline spray for a blocked nose.
- Ask about second-trimester screening tests.
- Make sure you're getting enough calcium.
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 15?
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 15 weeks pregnant?
At 15 weeks pregnant, your baby is about the size of an apple. That is about 10.1 cm (4 in) from crown to rump, weighing about 70 g (2.5 oz).
How big is my belly at week 15 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.
Can I take a decongestant for pregnancy congestion?
Start with drug-free options such as saline nasal spray or rinses, a humidifier, raising the head of your bed, and drinking plenty of water. Some decongestant medicines are not recommended in pregnancy, so check with your doctor, midwife, or pharmacist before taking any. If you also have a fever, facial pain, or thick colored mucus, see your provider, as these can be signs of an infection.
What is amniocentesis, and is it risky?
Amniocentesis is a diagnostic test in which a small amount of amniotic fluid is taken with a thin needle to check the baby's chromosomes and some genetic conditions. It is usually done from about 15 weeks and is offered when screening shows a higher chance of a condition or for other medical reasons. It carries a small risk of miscarriage, which your provider can explain before you decide.
Can I find out the sex at 15 weeks?
Sometimes, but an ultrasound at 15 weeks isn't always reliable, because the genitals are still developing and the baby's position can hide them. If you had NIPT, it can usually tell you the sex chromosomes already. Otherwise, most people find out at the anatomy scan at around 18 to 22 weeks, if they want to know and the baby's position allows.
What trimester is 15 weeks pregnant?
Week 15 is in the second trimester, which covers weeks 14 to 27.
How many months is 15 weeks pregnant?
15 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.