13 weeks pregnant

13 weeks pregnant is about 3 months. It falls in the third month of pregnancy. You are in week 13 of 40, in the first trimester. Here is what is happening with your baby and your body this week.

Your baby at 13 weeks

Vocal cords are forming, and the intestines move from the umbilical cord into the abdomen.

Your baby's fingertips now carry the beginnings of fingerprints, the unique patterns of ridges that will stay with them for life. The bones in the arms and legs are starting to harden, and the arms have grown to a length that is more in proportion with the rest of the body.

The ovaries or testes are fully formed inside, even though the outside genitals are still developing. The baby can bring a hand toward the mouth, and the mouth itself is practicing opening and closing. The tiny pancreas has started producing insulin, and the liver is beginning to make bile, both early signs of a digestive system getting ready for life outside the womb.

The head still makes up a large share of your baby's length, but from now on the body will grow faster, so proportions will steadily even out.

Your body at 13 weeks

This is the last week of the first trimester. The risk of miscarriage drops significantly.

As you near the end of the first trimester, you may notice your energy slowly returning and your appetite picking up. Your breasts may still be growing and could start making small amounts of colostrum later in pregnancy, so changes there are normal. Many people notice more thin, milky vaginal discharge, called leukorrhea, which is caused by higher estrogen and increased blood flow. It is usually harmless, but tell your provider if it becomes itchy, smells unpleasant, changes color, or is watery. Some people also notice changes in their sex drive around now.

Your belly at week 13

In month 3 (weeks 9–13) most people still don't look pregnant. Around 12 weeks the uterus rises out of the pelvis, and its top can be felt just above your pubic bone.

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 13 weeks pregnant

• Gradually returning energy
• Increased appetite
• Thin, milky vaginal discharge
• Changes in sex drive
• Bloating or constipation
• Growing breasts

Checkups around week 13

Week 13 is still within the usual window for the nuchal translucency scan and combined screening, which generally needs to be done by around 14 weeks. If you haven't had your first-trimester scan or screening yet, check with your provider about timing. What is offered varies by country and clinic.

Common symptoms in the first trimester

The first trimester runs from week 1 to week 13. It is when your baby's major organs, spine and heart form, and when many people feel the most tired and nauseous. Not everyone has every symptom, and it is normal for symptoms to come and go. Common ones include:

• Nausea and vomiting (morning sickness), which can happen at any time of day
• Tiredness and needing more sleep
• Tender, swollen breasts
• Needing to urinate more often
• Food aversions or cravings and a metallic taste
• Mood swings
• Light spotting around implantation

Read the full first trimester guide.

When to call your doctor or midwife

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Frequently asked questions

How big is my baby at 13 weeks pregnant?

At 13 weeks pregnant, your baby is about the size of a lemon. That is about 7.4 cm (2.9 in) from crown to rump, weighing about 23 g (0.8 oz).

How big is my belly at week 13 of pregnancy?

In month 3 (weeks 9–13) most people still don't look pregnant. Around 12 weeks the uterus rises out of the pelvis, and its top can be felt just above your pubic bone. Bump size, shape and when you start to show vary a lot from person to person.

Is 13 weeks the first or second trimester?

It depends on who you ask. Many sources, including ACOG, count the second trimester as starting at 14 weeks, which makes week 13 the last week of the first trimester. Others count it as the beginning of the second. The difference doesn't change your care, and the gradual improvement many people feel around now happens regardless of how the weeks are labeled.

How likely is a miscarriage after 13 weeks?

Most miscarriages happen in the first trimester, so the risk drops considerably once you reach this stage, especially after a scan has shown a healthy heartbeat. Pregnancy loss later on is much less common, but it can still happen. Contact your doctor or midwife straight away if you have heavy bleeding, cramping pain, or fluid leaking from the vagina.

Can I still sleep on my back at 13 weeks?

Yes, sleeping on your back is generally fine in the first trimester. Your uterus isn't yet heavy enough to press on the large blood vessels that run along your spine. Later in pregnancy, side sleeping is usually recommended, so some people find it helpful to start getting used to it now. If you wake up on your back, don't worry; just roll over.

What trimester is 13 weeks pregnant?

Week 13 is in the first trimester, which covers weeks 1 to 13.

How many months is 13 weeks pregnant?

13 weeks pregnant is about 3 months. It falls in the third month of pregnancy. The third month covers weeks 9 to 13. 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.