How many months is 15 weeks pregnant?

15 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 15 weeks?

At 15 weeks, the baby is about the size of a apple, roughly 10.1 cm long and around 70 g. That is an average; healthy babies vary.

Do you show at 15 weeks pregnant?

Some people do and some don't, and both are normal. In a first pregnancy, many people don't look pregnant yet at 15 weeks. If this isn't your first baby, or you're carrying twins, you'll often show sooner. Your height, build and belly muscles also change how much shows. How big you look now says little about how your baby is growing. Your provider usually starts measuring the bump from about 20 weeks.

Is cramping normal at 15 weeks pregnant?

Mild cramps are common at 15 weeks, and there are a few usual causes. Stretching ligaments can cause a sharp cramp on one side of your lower tummy. Constipation and trapped wind are also common in pregnancy and can cause crampy pain. These usually ease with rest or a change of position. Contact your provider if it's severe or doesn't ease after 30 to 60 minutes of rest, or comes with bleeding, regular tightenings, unusual discharge or pain when you pee.

Is lower back pain normal at 15 weeks pregnant?

Yes, it's common. Pregnancy hormones soften your ligaments to get ready for birth, and this strains the joints of your lower back and pelvis. Bending your knees to lift, avoiding heavy loads, flat shoes, good back support when sitting, and a warm bath or massage can help. The NHS advises contacting your midwife or doctor promptly about back pain in the second trimester, as it can be a sign of early labour. Call straight away if it comes with fever, bleeding or pain when you pee.

Are there symptoms of a baby boy at 15 weeks?

No symptom can tell you. The only link researchers have found is small, and it points the other way. In a Washington State study of more than 2,000 women admitted to hospital for severe sickness early in pregnancy, the odds of having a girl were about 50% higher than in women without it. Plenty of people with severe sickness still have boys, so this can't predict your baby's sex. The mid-pregnancy anatomy scan can usually show it.

Where is the baby located at 15 weeks pregnant?

Low down. The baby is inside your uterus, which is rising out of your pelvis but still sits well below your belly button. Which way it lies doesn't matter at this stage. Early in pregnancy many babies lie sideways, and most settle head-down by the third trimester. You probably can't feel it moving yet, as first movements usually start between 16 and 24 weeks.

15 Weeks Pregnant

At 15 weeks pregnant, your baby measures about 10.1 cm from head to bottom, roughly as big as an apple. Fine, soft hair called lanugo is growing over the body, and eyebrows and eyelashes are starting to form. The eyes are now sensitive to light, even though the eyelids are still closed, and hearing is starting to develop. For many people, a small bump starts to show this month, often low down. This page covers what your 15-week belly may look like, which blood tests and scans happen around now, what a 15-week ultrasound can show, and what causes cramps and back pain at this stage.

What trimester is 15 weeks?

Week 15 is in the second trimester, which runs from week 13 to week 27 (NHS). It is week 3 of 15 in this trimester, and the third trimester starts at week 28.

Week 15 — second trimester, month 4; 25 weeks to go until your due date.
Baby's size — about a apple, ~10.1 cm.

Not sure it's 15 weeks? Try our due date calculator.

How big is your baby at 15 weeks?

Size of a

apple

Length, head to bottom

~10.1 cm

Weight

~70 g

Up from a peach last week to a apple now.

Baby development at week 15

The fetus is now sensing light, even though the eyelids are still fused shut — a bright torch on your belly may prompt movement away from it. Taste buds are forming, and the legs are growing longer than the arms. The bones are getting harder and will start showing up on scans. About the size of an apple.

What an ultrasound shows at 15 weeks

A scan isn't part of routine care at 15 weeks, and most people wait for the anatomy scan a few weeks from now. When a scan is done this week, for example to check on some bleeding, it can show the whole baby stretching and moving, and the heartbeat. The bones are getting harder this month, so the skeleton shows up clearly.

Week 15 is when the usual window for the quad screen opens. This blood test measures four substances made by the baby and the placenta. It can be done from 15 to 22 weeks and is most accurate between 16 and 18 weeks. It screens for Down syndrome and for neural tube defects, which affect the brain and spine. An unusual result does not mean your baby has a problem. Often the due date is just a little off, and follow-up tests can check. If a diagnostic test is needed, amniocentesis is usually done between about 15 and 20 weeks.

By 15 weeks the genitals have formed, so the sex may be visible on a scan. But a medical scan at this stage isn't meant to check it, and the baby's position often hides it. Some private studios offer extra scans just to see the sex or to take keepsake pictures. The US FDA discourages ultrasound done only for keepsakes. Ultrasound can slightly heat tissue, and the long-term effects of that are unknown.

Your body at 15 weeks

Increased appetite
Possible nosebleeds and congestion from extra blood flow
Mild swelling in the gums
Round-ligament aches

Your belly at 15 weeks

At 15 weeks, the top of your uterus has risen a little above your pubic bone but is still below the halfway point to your belly button. It usually gets to that halfway point at around 16 weeks and reaches the belly button at about 20. So a 15-week bump, if you can see one yet, sits low and is fairly small.

Other belly changes often start now. Brief, jabbing pains on the sides of the bump come from ligaments stretching as the uterus grows. Many people also notice more vaginal discharge, because more blood is flowing to the pelvic area. Normal discharge is clear, white or creamy and only slightly musky. See your provider if it changes colour, smells bad, turns frothy or lumpy like cottage cheese, or makes you itch, feel sore or sting when you pee.

Tips for week 15

Eat iron-rich foods to support the growing blood supply
Use a humidifier if congestion bothers you at night
Keep up regular dental care — pregnancy can affect gums

15 Weeks Pregnant: your questions

What trimester is 15 weeks?: Week 15 is in the second trimester, which runs from week 13 to week 27 (NHS). It is week 3 of 15 in this trimester, and the third trimester starts at week 28.
How many months is 15 weeks pregnant?: 15 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 15 weeks?: At 15 weeks, the baby is about the size of a apple, roughly 10.1 cm long and around 70 g. That is an average; healthy babies vary.
Do you show at 15 weeks pregnant?: Some people do and some don't, and both are normal. In a first pregnancy, many people don't look pregnant yet at 15 weeks. If this isn't your first baby, or you're carrying twins, you'll often show sooner. Your height, build and belly muscles also change how much shows. How big you look now says little about how your baby is growing. Your provider usually starts measuring the bump from about 20 weeks.
Is cramping normal at 15 weeks pregnant?: Mild cramps are common at 15 weeks, and there are a few usual causes. Stretching ligaments can cause a sharp cramp on one side of your lower tummy. Constipation and trapped wind are also common in pregnancy and can cause crampy pain. These usually ease with rest or a change of position. Contact your provider if it's severe or doesn't ease after 30 to 60 minutes of rest, or comes with bleeding, regular tightenings, unusual discharge or pain when you pee.
Is lower back pain normal at 15 weeks pregnant?: Yes, it's common. Pregnancy hormones soften your ligaments to get ready for birth, and this strains the joints of your lower back and pelvis. Bending your knees to lift, avoiding heavy loads, flat shoes, good back support when sitting, and a warm bath or massage can help. The NHS advises contacting your midwife or doctor promptly about back pain in the second trimester, as it can be a sign of early labour. Call straight away if it comes with fever, bleeding or pain when you pee.
Are there symptoms of a baby boy at 15 weeks?: No symptom can tell you. The only link researchers have found is small, and it points the other way. In a Washington State study of more than 2,000 women admitted to hospital for severe sickness early in pregnancy, the odds of having a girl were about 50% higher than in women without it. Plenty of people with severe sickness still have boys, so this can't predict your baby's sex. The mid-pregnancy anatomy scan can usually show it.
Where is the baby located at 15 weeks pregnant?: Low down. The baby is inside your uterus, which is rising out of your pelvis but still sits well below your belly button. Which way it lies doesn't matter at this stage. Early in pregnancy many babies lie sideways, and most settle head-down by the third trimester. You probably can't feel it moving yet, as first movements usually start between 16 and 24 weeks.

Useful at week 15

Pregnancy due date calculator — work out your due date from your last period
Massage in pregnancy — a gentle option for back pain
Is Tylenol safe in pregnancy? — if you need a painkiller for back pain
Pregnancy discharge by trimester — why there's more discharge now, and what's normal
Baby gender predictor — just for fun, while you wait for the anatomy scan

← 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.