First trimester · Week 6 of 40

Pregnancy week 6

A flicker of cardiac activity may appear on early ultrasound.

Approx. length0.4 cm
Approx. weighttoo early to weigh meaningfully
Size feelsesame seed
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Baby development at week 6

The embryo lengthens and limb buds begin. On some early scans, a rapid flicker marks early cardiac activity — exciting, but not every pregnancy is scanned this early.

Average size estimates for week 6 are about 0.4 cm and too early to weigh meaningfully — roughly sesame seed. Your ultrasound report and clinician’s dating override any website average.

What you might feel

Nausea and food aversions may intensify. Small, frequent meals and hydration often help — follow what your clinician recommends.

You are in the first trimester. Two pregnancies at the same week can feel completely different — treat these notes as orientation, not a checklist you must match.

What to track this week

A calm next step in Preglo

Track water and how you feel day to day. Patterns matter more than any single rough morning.

Also useful: due date calculator · all weeks · Preglo features

Nearby weeks: Week 4 · Week 5 · Week 7 · Week 8

Educational averages only — not medical advice. Contact your clinician for symptoms that worry you, bleeding, severe pain, or reduced movements.

Week 6 FAQ

How big is the baby at week 6?

Typical educational averages are about 0.4 cm long and too early to weigh meaningfully. Individual growth and measurement methods vary.

Which trimester is week 6?

Week 6 is generally counted in the first trimester (weeks 1–12 first, 13–27 second, 28–40 third in common educational grouping).

Should I track anything special this week?

Track water and how you feel day to day. Patterns matter more than any single rough morning.

Preglo

Track this week in Preglo.

Week tracker, kick counter, water log, and widgets — private on iPhone.

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