5 weeks pregnant

5 weeks pregnant is about 1 month. It falls in the second month of pregnancy. You are in week 5 of 40, in the first trimester. Here is what is happening with your baby and your body this week.

Your baby at 5 weeks

The neural tube, which becomes the brain and spinal cord, is forming. The heart begins to develop.

Your baby's cells are now organizing into three layers, each with its own job. The outer layer (ectoderm) will form the brain, nerves, skin, hair, and eyes. The middle layer (mesoderm) will become the heart, blood vessels, muscles, bones, and kidneys. The inner layer (endoderm) will form the lining of the gut, the lungs, the liver, and the bladder.

Along the back of the embryo, a groove folds up and begins to close into the neural tube. This process continues into next week. Your baby's heart starts out as a simple tube, and it begins to develop the first rhythmic contractions around the end of this week or early next week.

On an early transvaginal ultrasound, a doctor may now see the gestational sac and, often, the small round yolk sac inside it, though the embryo itself may still be too small to spot.

Your body at 5 weeks

Nausea, frequent urination, and mood changes may start as pregnancy hormones rise.

hCG roughly doubles every few days at this stage, and together with rising progesterone and estrogen, it is behind many of the symptoms that tend to appear now. Increased blood flow to your kidneys means you may need to urinate more often, even though your uterus is still small. Nausea may begin, food preferences can shift, and some people notice a metallic taste in the mouth. Feeling emotional or irritable is also common as hormones change quickly. Getting extra rest when you can really helps.

Your belly at week 5

In month 2 (weeks 5–8) you are not showing yet. Your uterus is slowly growing but is still tucked inside your pelvis. Bloating can make waistbands feel tighter.

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 5 weeks pregnant

• Nausea, sometimes with vomiting
• Frequent urination
• Metallic taste in the mouth
• Food aversions or cravings
• Mood swings
• Tiredness and sore breasts

Checkups around week 5

If you have not already, contact your doctor or midwife to book your first prenatal appointment. Some people are offered an early ultrasound around now, for example after a previous ectopic pregnancy, bleeding, or fertility treatment. Routine first scans usually happen later, and timing varies by country.

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

Have a question about week 5?

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Frequently asked questions

How big is my baby at 5 weeks pregnant?

At 5 weeks pregnant, your baby is about the size of a sesame seed. That is about 2 mm (0.08 in), weighing less than 1 g.

How big is my belly at week 5 of pregnancy?

In month 2 (weeks 5–8) you are not showing yet. Your uterus is slowly growing but is still tucked inside your pelvis. Bloating can make waistbands feel tighter. Bump size, shape and when you start to show vary a lot from person to person.

Can you see a baby on an ultrasound at 5 weeks?

Usually only partly. A transvaginal ultrasound at 5 weeks often shows the gestational sac and sometimes the yolk sac, but the embryo and heartbeat are often not visible yet. This is normal at this stage. If you have an early scan, your provider may suggest a follow-up scan a week or two later.

When does morning sickness start?

For many people, nausea begins somewhere between weeks 4 and 6, and it often eases by around weeks 12 to 14, though this varies. It can happen at any time of day. Contact your doctor or midwife if you cannot keep food or fluids down, as severe vomiting needs treatment.

Is it normal to have no symptoms at 5 weeks pregnant?

Yes. Many people have few or no symptoms this early, and symptoms often build gradually over the next few weeks. Having no nausea does not mean something is wrong. If you have a positive test and no pain or bleeding, a lack of symptoms alone is not a reason for concern.

What trimester is 5 weeks pregnant?

Week 5 is in the first trimester, which covers weeks 1 to 13.

How many months is 5 weeks pregnant?

5 weeks pregnant is about 1 month. It falls in the second month of pregnancy. The second month covers weeks 5 to 8. 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.