6 weeks pregnant: your baby & body
Your baby this week
About 0.5 cm — around the size of a lentil. Every baby grows a little differently.
How your baby is developing
- The heart typically begins beating around this week and can sometimes be seen on an early ultrasound.UNSW Embryology (CC-BY)
- The neural tube is closing, and small buds that will become arms are appearing.UNSW Embryology (CC-BY)
How you may feel
- Nausea and vomiting ('morning sickness', which can occur at any time of day) are common.NHS
- Heightened sense of smell and breast tenderness are frequently reported.NHS
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)
When to reach out
- Heavy vaginal bleeding or passing clots.ACOG
- Severe or persistent abdominal or pelvic pain.ACOG
- Severe, persistent nausea or vomiting that prevents keeping any fluids down (possible hyperemesis gravidarum).NHS
- Fever of 38°C (100.4°F) or higher, or chills.WHO
- Severe dizziness, fainting, or a racing/irregular heartbeat.NHS
- Pain or burning when urinating (possible urinary tract infection).NHS
These apply to this week specifically. See the full list of urgent warning signs the CDC publishes for pregnancy and the year after birth.
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.