Week 6 of Pregnancy: Your Baby Is the Size of a Lentil

TL;DR

• Your baby is the size of a lentil, about 5mm
• Facial features — nose, mouth, and ears — are starting to take shape
• Morning sickness may be in full swing this week
• Small, frequent meals can help ease nausea

Your Baby This Week

At six weeks, your baby has grown to about 5mm — roughly the size of a lentil — and is developing at a breathtaking pace. This week, something truly wonderful is happening: your baby's face is beginning to form.

Small depressions on the sides of the head are becoming the ears. Dark spots where the eyes will be are taking shape. Tiny openings that will become the nostrils are appearing, and the beginnings of the jaw and mouth are forming. It doesn't look like a face yet — more like a sketch of one — but the foundation is there. In just a few weeks, these basic structures will refine into recognizable features.

Your baby's heart is beating faster now, around 100 to 160 beats per minute — roughly twice as fast as yours. If you have an ultrasound this week, you might be able to see that tiny flicker on the screen. For many parents, this is the first moment pregnancy feels truly real.

The limb buds are growing, and though they look more like tiny paddles right now, they'll eventually develop into arms with hands and fingers, and legs with feet and toes. Inside the embryo, the intestines are forming, and the tissue that will become the lungs is starting to develop. The brain is growing rapidly, with different regions beginning to specialize.

Your Body This Week

If morning sickness hasn't arrived yet, week 6 is often when it makes its grand entrance. Nausea, dry heaving, and vomiting affect up to 80% of pregnant people, and hCG levels — which peak around weeks 8-10 — are climbing steeply right now.

Morning sickness can be all-day sickness. It might hit you first thing in the morning when your stomach is empty, or it might ambush you in the evening. Certain smells can trigger it — cooking meat, perfume, or even the smell of your partner's shampoo. Food aversions can be intense and seemingly random.

Beyond nausea, you might be dealing with bloating that makes your pants feel tighter even though your uterus is still very small. Progesterone slows down digestion, which leads to gas and that uncomfortable full feeling. You might also notice that you're more emotional than usual — crying easily, feeling anxious, or swinging between excitement and fear.

Breast changes are continuing too. Your breasts may feel heavier and more tender, and you might notice that the area around your nipples (the areola) is darkening. This is normal and is driven by increased blood flow and hormonal changes.

Common Questions at Week 6

I can't keep anything down. Is that normal?

Moderate morning sickness, while miserable, is common and generally not harmful to your baby. Your baby is getting what it needs from your body's reserves at this stage. However, if you're unable to keep any food or liquids down for 24 hours, losing weight, or feeling dizzy or faint, contact your healthcare provider. Severe, persistent vomiting could be a condition called hyperemesis gravidarum, which needs medical treatment.

Will the heartbeat be visible on ultrasound this week?

At six weeks, many ultrasounds can detect a heartbeat, though it depends on the exact timing and the position of the embryo. If your provider performs a transvaginal ultrasound and doesn't see a heartbeat yet, try not to panic. It may simply be too early. They'll usually ask you to come back in a week or two for a follow-up scan.

Is spotting normal at 6 weeks?

Light spotting can be normal in early pregnancy and affects about 15-25% of pregnant people in the first trimester. It can be caused by the cervix being more sensitive due to increased blood flow. However, if you experience heavy bleeding, bright red blood, or bleeding accompanied by severe cramping, contact your provider right away.

Why do I feel so bloated?

Progesterone relaxes smooth muscle throughout your body, including the muscles in your digestive tract. This slows everything down, leading to bloating and gas. It's one of those less glamorous early pregnancy symptoms, but it's completely normal. Eating smaller meals, staying hydrated, and gentle movement can help.

This Week's Tip

Small, frequent meals can help ease morning sickness. Instead of three large meals, try eating five or six smaller ones throughout the day. An empty stomach often makes nausea worse, so keeping something in your stomach at all times can help. Many people find that bland, starchy foods like crackers, toast, rice, and bananas are easiest to tolerate. Keep crackers on your nightstand so you can nibble a few before getting out of bed in the morning. Ginger — in tea, chews, or even ginger ale — can also help settle your stomach. Cold foods tend to be better tolerated than hot ones because they have less smell. If you find something that works for you, stick with it, even if it's an unusual food combination. Whatever stays down is a win.

Milestone: Heartbeat Detected

This week marks a truly special moment — your baby's heartbeat can be detected. That tiny flicker on an ultrasound screen is one of the first tangible signs of the new life growing inside you. Seeing or hearing your baby's heartbeat for the first time is often described as one of the most emotional moments of pregnancy. If you have an early ultrasound and get to witness this, take it in. It's real. Your baby's heart is beating. And it will keep beating, stronger and faster, throughout the rest of this incredible journey.

Sources

• American College of Obstetricians and Gynecologists (ACOG). How Your Fetus Grows During Pregnancy.
• Mayo Clinic. Fetal Development: The 1st Trimester.

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