15 weeks pregnant: baby, body and what to expect

Trimester 2 of 3About 3.5 months25 weeks to go

Week 15 of pregnancy: baby is about the size of a apple

Week 15 at a glance

At 15 weeks, the fetus is often about 10–11 cm (3.9–4.3 in) long, roughly the size of an apple. The skin is still thin, so blood vessels may be visible through it.

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

Your baby at 15 weeks

Baby Is About the Size of an Apple

At 15 weeks, the baby keeps growing quickly. The most noticeable change is that the skin is still thin and see-through.

What is happening this week

The fetus is often about 10–11 cm (3.9–4.3 in) long. The skin is still very thin, so blood vessels may show through, while fat and muscle continue to develop underneath.

Blood vessels may be visible through the thin skin.
The bones are continuing to harden, and the muscles keep getting stronger.
The baby is moving more, though these movements are usually too light to feel yet.

Around this stage, an ultrasound may show some body structures more clearly. What is seen depends on gestational age, the baby's position and image quality.

How this week may feel

Many people find they feel somewhat better than in the first trimester, but tiredness, heartburn or occasional nausea can continue. If discomfort gets worse, talk with your OB-GYN or midwife. Many providers recommend calling them about any new or changing symptoms.

Get medical care right away if you have bleeding, severe pain, fever, persistent vomiting, fluid leaking from the vagina, or sudden weakness or dizziness.

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Your body at 15 weeks

Stretch Marks and Skin Care at Week 15

Why do stretch marks appear?

By week 15, your bump may start to show more. Stretch marks form when the skin stretches quickly and small breaks develop in the deeper layers of the skin. The main factors are genetics, how fast your body stretches, and hormone changes. Many people develop some stretch marks during pregnancy, and they often fade to a lighter color after birth.

Stretch marks are a common change during pregnancy. Most people get some, and they are not a sign that something is wrong.

How to care for your skin

Moisturize: Lotions or oils can soften the skin and ease itching. They will not remove existing marks, and they may not stop new ones from forming.
Healthy weight gain: Ask your provider what weight gain is right for you. Your provider can help you plan healthy eating and activity.
Stay hydrated: Drinking enough water is good for your overall health, but it does not change how your skin stretches.

When to contact your provider

Call your healthcare provider if you have intense itching, a new rash, or redness, especially if the itching is worst on your palms or the soles of your feet. Some skin changes in pregnancy need treatment, and a provider should check them.

Common symptoms at 15 weeks

Stuffy or runny nose

Higher hormone levels can swell the lining of the nose, which may cause congestion or light nosebleeds. A saline spray or a humidifier at night may help, and mention any bleeding that won't stop to your care team.

Round ligament twinges

Sharp or pulling pain on the sides of the lower belly can happen as the muscles that support the uterus stretch. Moving slowly when you change positions and resting when you need to often eases it.

Increased appetite

Many people feel hungrier as the body needs more energy. Small, regular meals with protein and fiber can help you feel steady through the day.

Dizziness when standing

Blood vessels widen during pregnancy, so you may feel lightheaded if you stand up quickly. Rising slowly, staying hydrated, and sitting down if you feel faint can help.

Skin darkening

A dark line down the belly or patches of darker skin on the face are common as hormones change. Sunscreen and a hat outdoors can help these areas look less noticeable over time.

Constipation

Slower digestion can make bowel movements harder. Drinking water, eating fiber from fruits, vegetables, and whole grains, and staying active may help.

Your week 15 checklist

Keep prenatal appointments and write down questions as they come up. Drink water through the day and keep a bottle nearby. Choose comfortable, stretchy clothes and a supportive bra. Take your prenatal vitamin as your care team advised. Try a short daily walk or gentle stretching if you feel up to it. Rest when you feel tired, and plan for earlier bedtimes if needed.

Tests and appointments

Maternal blood screening (quad screen). This blood test, offered between about 15 and 22 weeks, checks the chances of certain chromosome conditions and neural tube defects. It is a screening test, so results show risk rather than a diagnosis.

For your partner: You can help by joining a prenatal visit or by asking what your partner wants to know about the next steps. Taking on household tasks, helping with meals, or offering a short walk together can ease fatigue and stress.

Questions about week 15

How many months is 15 weeks pregnant?

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

What trimester is 15 weeks?

Week 15 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 15 weeks?

At 15 weeks, the fetus is often about 10–11 cm (3.9–4.3 in) long, roughly the size of an apple. The skin is still thin, so blood vessels may be visible through it.

Can I prevent stretch marks with lotion?

Moisturizers may ease itching and dryness, but they have not been shown to reliably prevent stretch marks. Genetics and skin elasticity play a bigger role, and most pregnant people get some stretch marks.

Why do I have a stuffy nose during pregnancy?

Pregnancy hormones can increase blood flow and swell the tissues in the nose. Saline spray, a humidifier, and extra fluids may help, and a care team can advise you if symptoms are severe.

When might I start to feel the baby move?

Many people begin to notice small flutters somewhere around the middle of pregnancy, though it can be later for a first pregnancy. Every pregnancy is different, so tell your care team if you have concerns.

Safe or not?

Ask your doctorCan I run while pregnant?Generally OKCan you eat salmon while pregnant?Generally OKIs decaf coffee safe during pregnancy?Generally OKCan I eat honey when 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 16: Eyes Move Into Place and May Begin Responding to LightRead week 16 →

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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.