Week 6
Trimester 1Days 5+0 to 5+6
Baby is now the size of a lentil
Week 6 is often one of the most memorable weeks of early pregnancy. For many parents, symptoms become much more noticeable — nausea may begin or intensify, fatigue can feel overwhelming, and emotions may be running high. At the same time, your baby is developing at an astonishing pace. Tiny facial features are beginning to form, the neural tube is continuing to close, and the heart may now be beating.
Length
~4–6 mm
1.6 in–2.4 in
Weight
< 1 g
2.2 lb
Development highlights
- check_circleThe heart is developing rapidly and may already be beating.
- check_circleThe neural tube continues closing and will become the brain, spinal cord, and central nervous system.
- check_circleTiny dark spots are appearing that will become the eyes and nostrils.
- check_circleSmall folds are forming where the ears will eventually develop.
- check_circleTiny arm and leg buds are beginning to appear on the sides of the body.
This week's milestones
- check_circleThe heart may now be beating for the first time.
- check_circleEarly facial structures — eyes, nostrils, and ear folds — are beginning to form.
- check_circleArm and leg buds appear.
- check_circleThe neural tube continues to close.
Fun fact
Even though your baby is only about the size of a lentil, the heart may already be beating more than 100 times per minute.
Weekly checklist
- Continue taking prenatal vitamins.
- Stay hydrated throughout the day.
- Eat small, frequent meals if nausea is a problem.
- Schedule or prepare for upcoming prenatal appointments.
- Rest whenever possible.
- Start thinking about pregnancy announcements if you wish.
Frequently asked questions
Is it normal for symptoms to suddenly become stronger?
Yes. Many people notice a significant increase in symptoms around Week 6 as pregnancy hormones rise rapidly.
Can the heartbeat be seen on an ultrasound yet?
Sometimes. Early ultrasounds may detect cardiac activity around Week 6, but timing varies. It is not always visible at this stage and that does not necessarily mean something is wrong.
Is severe fatigue normal?
Yes. Extreme tiredness is very common during the first trimester. Your body is building a placenta and supporting rapid development — this takes a tremendous amount of energy.
What if I don't feel sick?
Not everyone experiences nausea. A lack of morning sickness does not automatically mean anything is wrong — many people have healthy pregnancies with few or no symptoms.
Related tools
shopping_bagHelpful picks for Trimester 1
Browse all pregnancy products →Frida Mom Anti-Nausea Acupressure Bands
Drug-free acupressure wristbands for morning sickness relief — wear during the first trimester to ease nausea without medication.
Lokaheadr 1st Pregnancy Essentials Kit
Curated first-pregnancy essentials gift set for new moms-to-be — everything you need for a comfortable first trimester.
Momcozy Maternity Pregnancy Pillow
Full-length maternity pillow with removable sections for bump support, back relief, and comfortable side sleeping.
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Medical information disclaimer
The content on this page is provided for general informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.
Always consult your GP, midwife, health visitor, paediatrician, or other qualified healthcare provider before making decisions about your health or your child's health and development. Never ignore or delay seeking professional advice because of something you have read on BabyScout. If you think there is a medical emergency, call 999 (UK) or your local emergency services immediately.