First trimester · Week 6 of 40
6 weeks pregnant: the size of a lentil
Cardiac activity can often be seen on a vaginal ultrasound. Buds for arms and legs appear.
Reviewed against ACOG, NHS and WHO guidance · Updated November 2026
Typical size
About 4–6 mm
15% of the way to your due date
Your baby this week
Cardiac activity can often be seen on a vaginal ultrasound. Buds for arms and legs appear.
Your body this week
Morning sickness often begins — nausea can happen at any time of day.
Tip for week 6
Eat small, frequent meals and keep plain crackers by your bed.
Carry this guide in your pocket
Mamivaa is a free pregnancy app with a week-by-week tracker, vitamin and water reminders, a food scanner and a baby checklist.
Start freeThis guide offers general information and does not replace advice from your doctor or midwife. If something feels wrong, contact your provider or emergency services.