Pregnancy Interval Growth - Twins Ultrasound Scan

Expecting twins? The Pregnancy Interval Growth – Twins Ultrasound Scan is your window into how both babies are developing week by week. At Cadabams Diagnostics, we combine advanced imaging with compassionate care to give parents confidence—and doctors the data they need to safeguard your pregnancy.

Quick Definition & Clinical Importance

This specialised ultrasound measures growth between visits rather than routine anatomy. It tracks:

• Each twin’s estimated fetal weight (EFW) and growth percentile
• Amniotic fluid levels around each baby
• Blood-flow patterns in umbilical & cerebral vessels
• Cervical length to predict pre-term labour risk Unlike a single anomaly scan, interval scans are repeated—fortnightly for monochorionic twins, every 3–4 weeks for dichorionic twins—to catch subtle changes early.

• Trans-abdominal scan – routine, full bladder recommended
• Trans-vaginal cervical length – optional if funneling suspected
• Doppler-enhanced scan – checks blood-flow discordance between twins

1. Estimated fetal weight & growth percentile
2. Amniotic fluid index (AFI) & deepest vertical pocket
3. Umbilical & middle cerebral artery Dopplers
4. Cervical length & presence of funneling
5. Placental location & cord insertion points

• Early detection of Twin-to-Twin Transfusion Syndrome (TTTS)
• Monitor selective fetal growth restriction (sFGR)
• Track cervical shortening to guide cerclage or steroid timing

Recommended Timeline

• Monochorionic twins: Every 2 weeks starting 16 weeks
• Dichorionic twins: Every 3–4 weeks starting 20 weeks

High-Risk Flags for Earlier or Extra Scans

• Vaginal bleeding or contractions
• Rapid abdominal distension (possible TTTS)
• Maternal hypertension or diabetes

• All confirmed twin pregnancies
• Triplets or higher on specialist request
• Selected high-risk singletons with growth concerns

1. Check-in & consent – 5 minutes
2. Scan protocol – biometry, Dopplers, cervical scan – 20–30 minutes
3. Instant results – printed images + digital report sent to your doctor within 15 minutes

• Informed timing of delivery—reduce NICU stays
• Lower perinatal morbidity & mortality
• Prompt referral for laser therapy or cerclage when indicated

• TTTS, TAPS, sFGR
• Conjoined twins (early detection before 14 weeks)
• Cervical insufficiency

Day Before

• Hydrate well for a full bladder (trans-abdominal)
• Empty bladder if trans-vaginal scan is scheduled On the Day
• Wear loose, two-piece clothing
• Bring previous scan reports & referral note

• Referral with confirmed chorionicity
• Maternal blood-pressure record
• No fasting required—eat normally!

• Report any bleeding or fluid leakage beforehand
• Mention allergies to ultrasound gel (rare)
• Arrive 10 minutes early for parking & paperwork