Second trimester · Pregnancy week by week
Week 21 of pregnancy
Baby is the size of a carrot. About 10.50 inches, 360g.
By week 21, fetal movements are routinely felt. Maternal mortality from preeclampsia in Black women is 3 to 5 times higher than in white women — symptoms must not be dismissed. Source
What's happening with the baby
The fetus is about 10.5 inches long. Eyebrows, eyelids, and eyelashes are well-formed. The fetus has a regular sleep-wake cycle. Bone marrow takes over blood-cell production from the liver.
What's happening for you
Bump is prominent. Many women feel hiccups (small rhythmic movements). Skin changes continue. Increased blood volume may cause shortness of breath with mild exertion.
Common (normal) symptoms this week
Regular fetal movements and hiccups, mild shortness of breath with exertion, lower back pain, occasional leg cramps, mild swelling of feet, breast colostrum.
Call your OB or 911 if
- Severe headache not relieved by acetaminophen.
- Vision changes — blurred vision, light flashes, floating spots.
- Severe right-upper-quadrant or upper-abdominal pain.
- Sudden swelling of face, hands, or feet.
- Vaginal bleeding or fluid leakage.
- Decreased fetal movement after 20 weeks.
- Persistent contractions before 37 weeks.
Why this week matters for Black families
Late in the second trimester is when preeclampsia becomes diagnosable (after 20 weeks). Black women have a 60% higher rate of preeclampsia and a 3x higher rate of preeclampsia-related death. The diagnosis combines new-onset blood pressure ≥140/90 with signs of organ stress. Track your own blood pressure between visits if you can — many Black-led OB practices recommend a home cuff at this stage. If your readings trend up, call your OB before the next appointment, not at it.
What to do this week
Continue BP tracking. Schedule a tour of your delivery hospital. If you haven't picked an OB or midwife, this is the cutoff to switch (most won't accept new patients past 24 weeks). If you have a doula, finalize the contract and confirm Medicaid coverage if applicable.
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References
- ACOG Practice Bulletin 222.
- NIH NICHD Pregnancy Resources.
Last medically reviewed: .
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