New criteria for pregnancy all scans with months and indicator .
Reading File
Do you mean a pregnancy ultrasound schedule, listing each scan by pregnancy month and its indication?
Asking for Preferences
What would you like included? · Which guideline setting should I use?
Do you mean a pregnancy ultrasound schedule, listing each scan by pregnancy month and its indication?
Reading File
Searching the Web
WHO antenatal care ultrasound routine pregnancy before 24 weeks recommendations indications ultrasound scans
Searching PubMed
pregnancy ultrasound screening
Finding Sources
Pregnancy ultrasound scans: month, timing, and indication
| Pregnancy month | Usual gestational age | Scan / test | Main indication and what it checks |
|---|---|---|---|
| 1-2 months | 6-9 weeks | Early viability / dating scan | Confirm an intrauterine pregnancy, fetal heartbeat and viability; estimate gestational age; check number of fetuses; assess pain or bleeding for ectopic pregnancy or miscarriage. |
| 3 months | 11 weeks to 13 weeks + 6 days | First-trimester screening / NT scan | Nuchal translucency (NT), nasal bone and early fetal anatomy. Used with maternal blood tests or NIPT for screening risk of chromosomal conditions such as trisomy 21. Also confirms dates, twins, and chorionicity in multiple pregnancy. |
| 4-5 months | 18-22 weeks | Detailed anomaly scan / level-II scan | Screens fetal brain, spine, face, heart, kidneys, limbs, abdomen, placenta, amniotic fluid, cervical length, fetal growth, and structural congenital anomalies. |
| 5-6 months | 22-24 weeks | Fetal echocardiography, only if indicated | Detailed fetal heart assessment when there is suspected cardiac defect, abnormal NT/anomaly scan, maternal diabetes, certain medicines/infections, assisted conception, or a family history of congenital heart disease. |
| 6-7 months | 28-32 weeks | Growth scan with Doppler, if indicated | Assesses fetal growth, amniotic fluid, placental location and blood flow. Indications include hypertension/preeclampsia, diabetes, suspected fetal growth restriction, reduced fetal movements, twins, placental problems, or prior poor obstetric outcome. |
| 8 months | 32-34 weeks | Repeat growth and Doppler scan, if indicated | Follow-up for growth restriction, abnormal Doppler, low fluid, multiple pregnancy, hypertension, diabetes, or a previously low-lying placenta. |
| 9 months | 36-37 weeks | Presentation / well-being scan, if indicated | Checks fetal presentation such as breech, growth, fluid, placenta and Dopplers. Useful when there is reduced movement, suspected growth issue, hypertension, diabetes, twins, or uncertain presentation. |
Routine versus indicated scans
- The WHO minimum recommendation is one ultrasound before 24 weeks, mainly to establish gestational age, detect multiple pregnancy and fetal anomalies, and reduce unnecessary induction for presumed post-term pregnancy. See the WHO ultrasound recommendation.
- In many obstetric practices, especially in India and high-resource settings, two routine scans are commonly offered:
- Dating/NT scan at 11-13+6 weeks
- Detailed anomaly scan at 18-22 weeks
- Third-trimester scans are not automatically needed for every low-risk pregnancy. They should be done when there is a maternal, fetal, placental, or multiple-pregnancy indication.
Indications for extra scans or Doppler surveillance
Additional ultrasound may be needed for:
- Vaginal bleeding, pain, or suspected ectopic pregnancy
- Uncertain last menstrual period or uncertain gestational age
- Previous miscarriage, ectopic pregnancy, stillbirth, or fetal growth restriction
- Twin or higher-order pregnancy
- High blood pressure, preeclampsia, diabetes, thyroid disease, kidney disease, autoimmune disease
- Reduced fetal movements
- Fundal height smaller or larger than expected
- Suspected low amniotic fluid or excess amniotic fluid
- Low-lying placenta/placenta previa
- Suspected fetal growth restriction or large-for-gestational-age fetus
- Breech or uncertain fetal presentation near term
- Abnormal findings in an earlier scan or genetic screening test
Important: NT, anomaly scanning, NIPT, and blood screening tests are screening, not confirmation of a genetic condition. A high-risk result may need diagnostic testing such as chorionic villus sampling or amniocentesis after obstetric/genetic counseling.
Recent evidence continues to assess the accuracy of first- and second-trimester structural ultrasound screening, including a 2024 Cochrane review.
This is a shared conversation. Sign in to Orris to start your own chat.