Your Prenatal Testing Timeline: What Each Check-up Actually Looks For

Prenatal care shouldn't be a black box. Understanding what each test looks for makes the whole 40 weeks calmer.

First trimester (6–13 weeks)

• 6–8 wks · dating ultrasound: confirms the pregnancy is in the uterus, checks the heartbeat, and sets your official due date — more reliable than period math
• 8–12 wks · booking bloods: blood count, blood type (incl. Rh), liver/kidney panels, infection screening, thyroid
• 11–13⁶ wks · NT scan: nuchal translucency, a key early marker for chromosomal risk; the window is strict and can't be made up later

Second trimester (14–27 weeks)

• 15–20 wks · serum screening / NIPT: chromosomal risk screening; NIPT is more accurate
• 20–24 wks · anatomy scan: a systematic organ-by-organ check — the most important ultrasound of pregnancy
• 24–28 wks · glucose test (OGTT): screens for gestational diabetes — a positive is manageable, usually with diet and movement

Third trimester (28 weeks–birth)

• From 28 wks: visits go from monthly to fortnightly, then weekly after 36
• 28–32 wks: growth scan — pace of growth and baby's position
• 35–37 wks · GBS swab: a positive just means antibiotics in labour; it doesn't affect vaginal birth
• From 36 wks: weekly monitoring (NST); 37 weeks is full term

Three practical notes

1. Count kicks from 28 weeks: same time daily; 10 movements within 2 hours is reassuring. A clear decrease in movement is the one symptom that warrants going in immediately
2. NT, anatomy and glucose tests have hard windows — book ahead
3. A "borderline" result is risk stratification, not a diagnosis — don't panic before follow-up

Schedules vary by country and provider; follow your own clinic's plan. This explains the system — it doesn't replace medical advice.