Second trimester
21 weeks pregnant
Baby is about the size of a carrot.
Week 21 of 40 · in your second trimester · Updated
Your baby this week
Baby swallows amniotic fluid and pees it back out — practice for life outside!
- Baby is regularly swallowing small amounts of amniotic fluid — this helps develop the digestive system.
- Tiny taste buds are forming on the tongue.
- Bone marrow now produces blood cells (this work was previously done by the liver and spleen).
Your body this week
Stretch marks and itchy skin can start. Lotion is your friend.
- Skin stretches rapidly across your belly, breasts, and thighs — itchiness is common.
- Vivid dreams continue, sometimes nightmares.
- You may feel ravenous — eat balanced meals with protein.
Common symptoms
- Itchy stretching skin
- Vivid dreams
- Big appetite
- Stretch marks
- Varicose veins
Things to do this week
- Moisturize daily
- Eat balanced meals with protein at every meal
- Wear support stockings if you have varicose veins
For partners this week
Hands-on help
- Offer to rub lotion on itchy, stretching skin.
- Plan meals with protein at every one.
Typical visits around this week
Based on a typical schedule in Ontario. Your doctor or midwife sets the actual timing.
Routine check-ups (about every 4 weeks)
Weeks 12–28
Check-ups are often about every 4 weeks until around 28 weeks. Your provider usually checks your blood pressure, weight and urine, listens to the baby's heartbeat and measures your growing belly. Some people need more visits.
Questions to ask →Questions to ask ↑
- Is my blood pressure and weight gain on track?
- Is this symptom I've been having normal?
- What should I be doing about exercise, work or travel right now?
- What's coming up before my next visit?
Anatomy (detailed) ultrasound
Weeks 18–22
A detailed ultrasound, usually at 18–22 weeks, that looks at the baby's brain, face, heart, spine, organs, arms and legs, and checks growth and where the placenta is.
Questions to ask →Questions to ask ↑
- Can my partner come, and can we have pictures?
- Where is the placenta, and does that matter for us?
- When will my provider go over the results with me?
- If we want to know the sex, can it be shared at this scan?
Coming up
Gestational diabetes screening
Weeks 24–28
A blood sugar test offered to everyone between 24 and 28 weeks. It usually starts with a sweet drink and a blood test an hour later; if that result is high, a longer fasting test follows. Some people are tested earlier.
Questions to ask →Questions to ask ↑
- Do I need to fast or change what I eat beforehand?
- How long should I plan to be at the lab?
- When will I hear about my results?
- What happens if I need the second test?
A flu shot and a COVID-19 vaccine are recommended at any stage of pregnancy. The flu shot is given during flu season, so the timing depends on when you're pregnant.
When to call your doctor or midwife
Bleeding, fluid leaking, a bad headache or vision changes, or baby moving less than usual all need a call. See the warning signs and who to call →
Follow your pregnancy week by week in MyBabyBase.
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Further reading from health authorities
- Pregnancy — Government of Canada (Public Health Agency of Canada)
- Your pregnancy — Pregnancy Info, from the Society of Obstetricians and Gynaecologists of Canada (SOGC)
- Week-by-week guide to pregnancy — NHS (UK)
- Pregnancy — American College of Obstetricians and Gynecologists (ACOG)