Second trimester · Pregnancy week by week
Week 23 of pregnancy
Baby is the size of a grapefruit. About 11.40 inches, 500g.
Week 23 is preterm-labor screening territory. Black women have 2x higher rates of preterm birth (before 37 weeks), per CDC NCHS — cervical-length screening is critical at this stage. Source
What's happening with the baby
The fetus is more than 11 inches long. Lungs continue developing. Pancreas matures. Skin is still wrinkled but beginning to fill out as fat is deposited.
What's happening for you
Stretch marks may worsen. Lower back pain is common. Some women experience first Braxton Hicks contractions (irregular tightening). Pelvic discomfort increases as the uterus expands.
Common (normal) symptoms this week
Stretch marks, Braxton Hicks contractions (irregular, painless tightening), lower back pain, pelvic discomfort, regular fetal movements, occasional headaches.
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
Discuss preterm-labor risk with OB. If you have a short cervix, prior preterm birth, or other risk factors, ask about cervical-length screening (transvaginal ultrasound) and progesterone supplementation (vaginal or IM 17-OHP). Continue BP tracking. Begin third-trimester planning.
Pregnancy / baby
Babylist
Universal baby registry across every store, with curated lists vetted by parents. Includes a Black-owned brands collection.
Start a registryAffiliate link — we may earn a commission at no extra cost to you.
References
- ACOG Practice Bulletin 234 — Periviable Birth.
- CDC NCHS Data Brief 387 — Preterm Birth.
Last medically reviewed: .
Free tools
Track your due date + check benefits eligibility
Estimate your due date, see your trimester at a glance, and check Medicaid + WIC eligibility for your state.