5 Weeks Pregnant
Reviewed by Safi Allah Khan
Medically reviewed by: Safi Allah Khan · Written by the Momi team · Last updated 20 October 2026
Quick answer: At 5 weeks pregnant, your baby is about the size of a sesame seed, about 2 mm (0.08 in) long. You're in the first trimester, in month 2, with 35 weeks to go until your due date. This week's milestone: neural tube and heart begin forming. Symptoms vary from person to person.
| Week 5 at a glance | |
|---|---|
| Trimester | First |
| Month | 2 |
| Weeks to due date | 35 |
| Baby's size | About the size of a sesame seed |
| Length | About 2 mm (0.08 in) |
| This week | Neural tube and heart begin forming |
Sizes are typical averages. Before about 20 weeks, length is measured crown to rump; after that, head to heel.
Your baby at 5 weeks
Your baby is about the size of a sesame seed. The neural tube, which becomes the brain and spinal cord, is forming, and the early heart tissue is beginning to develop.
Your body at 5 weeks pregnant
Hormones are rising fast. You may feel very tired, a little sick, bloated or emotional. Some people have no symptoms yet, which is also normal.
Things to do this week
- Book your first prenatal appointment if you haven't yet.
- Eat small, frequent meals if you feel queasy.
- Make sure you are taking folic acid every day.
When to call your doctor or midwife
Contact your care team straight away if:
- you have vaginal bleeding, especially with cramps or belly pain
- you have severe or one-sided belly pain, or pain in the tip of your shoulder
- you are vomiting so often you can't keep fluids down (the CDC flags being unable to drink for more than 8 hours)
- you have a fever of 100.4°F (38°C) or higher
- it hurts or burns when you pee
If something feels wrong, trust that feeling and call. In an emergency, call your local emergency number.
Track week 5 in Momi
Use Momi's appointment reminders to save the date of your first visit so you don't miss it. Momi follows your pregnancy week by week with your baby's size and development, and keeps your diary, bump photos, appointments, kick counts and contractions in one place.
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Keep reading
← 4 weeks pregnant · All weeks · 6 weeks pregnant →
Sources
- ACOG: Changes During Pregnancy (infographic)
- NHS: Signs and symptoms of pregnancy
- ACOG: Morning Sickness: Nausea and Vomiting of Pregnancy
- CDC: Urgent Maternal Warning Signs
Medical disclaimer: Momi and this website provide general information, not medical advice. Always talk to your doctor or midwife; in an emergency call your local emergency number.
FAQ
How big is a baby at 5 weeks pregnant?
On average, a baby at 5 weeks is about the size of a sesame seed: about 2 mm (0.08 in). These are typical averages, and healthy babies vary.
How many months is 5 weeks pregnant?
5 weeks pregnant is in the second month of pregnancy and the first trimester. Months don't divide evenly into 40 weeks, so different sources may label the month slightly differently.
What should I do at 5 weeks pregnant?
Book your first prenatal appointment if you haven't yet. Eat small, frequent meals if you feel queasy.
Related guides
Track this in Momi
Momi is a free pregnancy tracker app for iPhone and Android that follows pregnancy week by week, estimates the due date, and keeps a pregnancy journal, weight log, kick counter and contraction timer in one place.
