Week 4
A Single baby's-breath floret (~2–4 mm) holds the scale of this week: tiny, bright, and complete enough to catch the eye when you look closely.
This week at a glance
Size
No size is stated — pregnancy is dated from before conception, and there is nothing yet to measure.
The flower
Baby's-breath floret (~2–4 mm) — this week’s plate, drawn at your baby’s scale.
You might notice
No symptoms · Missed period · Tired · Tender breasts · Nausea
How big is the baby at 4 weeks?
No size is stated at week 4. Pregnancy is dated from the first day of your last period, so the earliest weeks come before there is anything to measure — this page says so rather than inventing a comparison.
The embryo is about 2 mm long and growing quickly. It sits within an amniotic sac beside a yolk sac, while an outer layer of cells begins the work that will later become the placenta.1
4 weeks pregnant is how many months?
Week 4 falls in the first month of pregnancy. Weeks and months don’t divide evenly, and your antenatal care counts in weeks — so Zohra keeps weeks, and prints the month for the relatives who ask.
That puts you in the first trimester (weeks 1–13).
What might you be noticing?
You may notice no symptoms at all, or a missed period may be the first clue. Tiredness, breast tenderness, and nausea can also begin during the first trimester.1
Put a snack and water somewhere easy to reach. Start a simple question list for a future appointment, adding only what matters to you.
For the record: What was the first small detail that made this week feel different? — this week’s page in the app asks the same thing. All forty prompts are here.
Written from the sources above and checked against them. Not reviewed by a clinician — see the editorial policy. Zohra is a journal, not medical care; for anything worrying, talk to your midwife or doctor.