Free family guide · Pregnancy week by week · First trimester

6 weeks pregnant

Week 6 is in the first trimester in both the US Office on Women's Health (OWH) system and the UK's NHS week-by-week guide.[1][2]

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Sources on this page: OWH; NHS; ACOG; NICHD; NIMH; HRSA; CDC; MedlinePlus

This page shares what health organizations say. It is not medical advice. It is general information. Talk to your doctor, midwife or pediatrician about your own situation.

In an emergency, call 911.

At a glance

  • The NHS says the embryo is around 6 mm long.[3]
  • The NHS says the embryo looks like a tadpole at this stage, with limb buds forming and small dents where the ears will be.[3]
  • For nausea, the NHS suggests keeping a snack by the bed and eating 6 small meals a day.[3]

Which trimester is week 6?

OWH counts the trimesters as weeks 1 to 12, 13 to 28 and 29 to 40.[1] The NHS guide counts them as weeks 4 to 12, 13 to 27 and 28 to 41.[2] ACOG counts the first trimester to 13 weeks 6 days, the second from 14 weeks to 27 weeks 6 days, and the third from 28 weeks to 40 weeks 6 days.[4]

All three place week 6 in the first trimester.[1][2][4]

ACOG says pregnancy is counted from the first day of the last menstrual period, so 2 weeks are counted at the beginning when you are not yet pregnant.[4]

Your body this week

The NHS lists these symptoms around week 6:[3]

  • mood swings;[3]
  • headaches;[3]
  • peeing more often;[3]
  • vaginal discharge;[3]
  • darker patches of skin on the face, called chloasma.[3]

The NHS says nausea is often worse on waking.[3] It says a lot of people start to feel better after the first trimester, after 12 weeks.[3]

Your baby this week

The NHS says the embryo is around 6 mm long.[3]

The NHS says the embryo looks like a tadpole at this stage, with limb buds forming and small dents where the ears will be.[3] It says the heartbeat can sometimes be seen on a vaginal scan.[3]

Visits and tests around week 6

The NHS says its dating scan is done at 8 to 14 weeks.[5]

For a healthy pregnancy, NICHD describes visits once a month until 28 weeks.[6]

Things to do this week

  • For nausea, the NHS suggests keeping a snack by the bed and eating 6 small meals a day.[3]
  • The NHS says to talk to your midwife or doctor if you cannot keep food down.[3]
  • The NHS says to rest when you can.[3]
  • ACOG says taking a prenatal vitamin can lower the risk of severe nausea.[7]

Feelings check-in

The National Institute of Mental Health (NIMH) says perinatal depression includes depression during pregnancy, and its signs last at least 2 weeks.[8]

HRSA says the National Maternal Mental Health Hotline, 1-833-852-6262, takes calls and texts 24/7 in English and Spanish.[9]

When to call your provider or get help

CDC lists urgent warning signs to watch for during pregnancy and in the year after birth, including:[10]

  • a headache that will not go away or gets worse;[10]
  • dizziness or fainting;[10]
  • a fever of 100.4°F (38°C) or higher;[10]
  • severe nausea and vomiting;[10]
  • severe belly pain that does not go away;[10]
  • vaginal bleeding or leaking fluid;[10]
  • thoughts of harming yourself or the baby.[10]

MedlinePlus says some people spot in early pregnancy and do not miscarry, but any bleeding should prompt a call to a provider.[11]

Questions families ask

Which trimester is week 6?

OWH places week 6 in the first trimester.[1] The NHS guide places it in the first trimester.[2] ACOG places it in the first trimester.[4]

How big is the baby at 6 weeks?

The NHS says the embryo is around 6 mm long.[3]

When does morning sickness stop?

ACOG says it usually starts before 9 weeks, and for most women it goes away by 14 weeks.[7] The NHS says it usually clears up by weeks 16 to 20.[12]

Free from UpOnly Learning. Written for families of every faith. No outside ads and no affiliate links. Every fact on this page comes from the sources listed below. How we source and review these pages

Updated 2026-10-24: first published.

Sources

All sources were opened and checked on the date shown.

  1. Office on Women's Health (HHS). Stages of pregnancy. Checked October 24, 2026.
  2. NHS (United Kingdom). Week-by-week guide to pregnancy. Checked October 24, 2026.
  3. NHS (United Kingdom). 6 weeks pregnant guide. Checked October 24, 2026.
  4. American College of Obstetricians and Gynecologists. How Your Fetus Grows During Pregnancy. Checked October 24, 2026.
  5. NHS (United Kingdom). 4 weeks pregnant guide. Checked October 24, 2026.
  6. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NIH). What happens during prenatal visits?. Checked October 24, 2026.
  7. American College of Obstetricians and Gynecologists. Morning Sickness: Nausea and Vomiting of Pregnancy. Checked October 24, 2026.
  8. National Institute of Mental Health (NIH). Perinatal Depression. Checked October 24, 2026.
  9. Health Resources and Services Administration (HRSA). National Maternal Mental Health Hotline. Checked October 24, 2026.
  10. Centers for Disease Control and Prevention (HEAR HER campaign). Urgent Maternal Warning Signs and Symptoms. Checked October 24, 2026.
  11. MedlinePlus (National Library of Medicine). Miscarriage. Checked October 24, 2026.
  12. NHS (United Kingdom). Vomiting and morning sickness. Checked October 24, 2026.