6 Weeks Pregnant: Baby Size, Symptoms and What to Do

Your baby this week

Your baby is about the size of a pea. Small buds that will become arms and legs appear, along with little dents where the ears will be. On a transvaginal ultrasound, the heartbeat can sometimes be seen.

At 6 weeks a transvaginal ultrasound can often pick up cardiac activity, if you have a scan this early. If it isn't visible yet, that isn't necessarily a problem at this stage; a repeat scan a week or two later usually clears things up. The provider also measures crown-rump length, which can fine-tune your due date. The embryo is curved like a C, and limb buds are just appearing. Fatigue is often at its worst now because your body is pouring energy into building the placenta. Rest when you can and share the load. Mild, period-like cramps can happen, but heavy bleeding, pain that spreads to your shoulder or feeling faint needs urgent care.

By the numbers

Week 6 covers days 42 to 48 counted from the first day of your last period, which is 15% of a 40-week pregnancy. About 238 days remain until a 40-week due date. By date of conception, your baby is about 4 weeks old.

Pregnancy is dated from the first day of your last period, so conception happens around week 2. Your due date is 280 days (40 weeks) from that day, and an early ultrasound may adjust it.

Your body

Nausea, a sharper sense of smell and mood swings are common now. Small, frequent snacks can help. Call your provider if you can't keep fluids down, pee very little, or feel dizzy when you stand up.

Tests and to-dos this week

If you haven't yet, book your first prenatal visit with an OB-GYN or midwife. Ask which of your current medications and supplements are fine to keep taking.

• First prenatal visit · weeks 6–10 · visit

  Health history, physical exam and first-trimester labs. After that, visits are typically monthly until 28 weeks, every 2 weeks until 36 weeks, then weekly.

• First-trimester labs · weeks 6–13 · test

  Blood type and Rh factor, antibody screen, blood count, and infection screening including syphilis (ACOG recommends syphilis testing at the first visit, in the third trimester and at delivery).

Coming up: First-trimester screening (blood test + NT ultrasound) (from week 10). Full prenatal visit schedule

Tips for the first trimester

• Take 400 micrograms of folic acid a day; your provider may advise a higher dose if neural tube defects run in your family.
• Avoid alcohol, smoking, raw or undercooked meat, fish and eggs, and unpasteurized dairy.
• For nausea, try small, frequent meals and sipping fluids; call your provider if you can't keep anything down.
• Check every medicine and supplement you take with your provider or pharmacist before continuing.

Last week and next week

Last week (5): Still about the size of a sesame seed, your embryo is busy.

Next week (7): The brain is growing faster than anything else right now, which gives your baby a big forehead.

Frequently asked questions