Week 5 marks the beginning of a critical development phase. The embryo is growing rapidly, and the foundations of the heart, brain, and spinal cord are taking shape. You may also be experiencing your first real pregnancy symptoms. Use our Due Date Calculator to find your estimated delivery date.
Key Takeaways
- The embryo is about 2 mm (sesame seed size) and has differentiated into three cell layers that will form every organ in the body.
- A primitive heart tube is forming this week and will begin beating between weeks 5 and 6.
- Nausea and fatigue often begin around week 5 as hCG levels climb rapidly — both are signs of a healthy pregnancy.
- Adequate folic acid intake now is critical: the neural tube, which becomes the brain and spinal cord, is forming this week (ACOG).
Your Baby This Week
Size: Sesame seed (about 2 mm)
The embryo now has three distinct layers of cells that will become every organ and tissue in the body:
- Ectoderm (outer layer): Brain, spinal cord, nerves, and skin
- Mesoderm (middle layer): Heart, bones, muscles, kidneys, and blood vessels
- Endoderm (inner layer): Lungs, liver, pancreas, and digestive tract
A primitive heart tube is forming and will begin beating sometime between now and week 6. The neural tube, which becomes the brain and spinal cord, is also developing. Track your baby's growth with our Milestone Tracker.
Your Body
Pregnancy symptoms often kick in around week 5 as hCG levels climb rapidly:
- Nausea (with or without vomiting), often called morning sickness but it can happen any time of day. See our morning sickness remedies for evidence-based relief tips.
- Extreme fatigue
- Frequent urination as blood flow to the kidneys increases
- Sore breasts that may feel heavier or tingly
- Food aversions or cravings
If you have no symptoms, do not worry. Some people sail through early pregnancy feeling fine.
What to Do This Week
- Eat small, frequent meals to help manage nausea. Crackers, ginger, and cold foods tend to be easier on the stomach.
- Stay hydrated. Aim for at least 8 glasses of water per day.
- Avoid raw or undercooked meat, unpasteurized dairy, and high-mercury fish like swordfish and king mackerel.
Common Questions
Is it normal to have no symptoms at 5 weeks?
Yes. Symptoms vary widely between individuals and even between pregnancies. The absence of symptoms does not mean anything is wrong.
When will I hear the heartbeat?
A heartbeat can usually be detected on a transvaginal ultrasound between weeks 6 and 7. Your provider may schedule your first ultrasound for around week 8 to get a clearer picture.
Frequently Asked Questions
Is it normal to have no symptoms at 5 weeks?
Yes. Symptoms vary widely between individuals and even between different pregnancies in the same person. No nausea or fatigue does not mean anything is wrong — some people feel fine throughout early pregnancy.
When will I hear the heartbeat for the first time?
A heartbeat can typically be detected on a transvaginal ultrasound between weeks 6 and 7. On an abdominal ultrasound, it may not be audible until week 8 or 9. Most providers schedule a first ultrasound around week 8 to 10.
What causes morning sickness, and when will it stop?
Morning sickness is thought to be caused by rapidly rising hCG levels, and possibly by increased estrogen sensitivity. It is called "morning" sickness, but it can occur at any time of day. For most people, nausea improves significantly by weeks 12 to 14.
What foods help with nausea at 5 weeks?
Eating small, frequent meals helps keep blood sugar stable. Bland foods like crackers, dry toast, and rice tend to be tolerated better. Ginger (tea, chews, or capsules) and vitamin B6 supplements have evidence supporting their effectiveness (ACOG, 2023).
Related Articles
- Pregnancy Week-by-Week Overview — see the full timeline
- Pregnancy Week 6: A Tiny Heartbeat — what comes next
- Nausea Relief in Pregnancy, practical tips for managing morning sickness
Sources
🔧 Helpful Tools
- Due Date Calculator — Calculate your estimated due date
- Contraction Timer — Track your contractions during labor
- All Baby Tools — Browse all free tools for pregnancy and baby care
