1 weeks pregnant: your baby & body
Your baby this week
About 0.1 cm — around the size of a poppy seed. Every baby grows a little differently.
How your baby is developing
- Weeks 1–2 are counted from the first day of the last menstrual period, before conception has actually happened — this is the standard way pregnancy dating works.NHS
How you may feel
- Because dating starts from the last period, there is usually nothing to notice yet — this is a good time to start a folic-acid supplement if trying to conceive.ACOG
Nutrition this week
- Folate (B9) — supports neural-tube closure — most critical in weeks 1–12 (Leafy greens)
- Iodine — fetal brain + thyroid development (Iodized salt)
- Vitamin B12 — with folate, for blood + nerves (Meat)
Part of the First trimester (weeks 1–13).
Educational reference only — not medical advice. Typical/average figures; every pregnancy differs. Always consult your doctor or midwife. Seek urgent care for any warning sign.