BEDSIDE ACTION BOX — Delivering Multiples
- Know the chorionicity before delivery — monochorionic twins share placental vessels and carry the highest risk.
- Prepare a separate resuscitation team and warmer for each baby; both may need support.
- In TTTS, expect a small, anemic donor and a large, plethoric, volume-overloaded recipient — check a hematocrit on each.
- Anticipate prematurity and growth restriction across multiples generally.
- Monoamniotic twins additionally risk cord entanglement — expect an early, often operative delivery.
1. Overview
The Core Idea
Multiple gestations carry higher rates of prematurity and growth restriction than singletons, but the single most important determinant of risk is chorionicity — whether the fetuses share a placenta. Monochorionic twins share placental vascular connections (anastomoses) that can transfer blood unevenly between them, producing twin–twin transfusion syndrome (TTTS) and related conditions.
Why This Topic Matters
Twins and higher-order multiples are an increasing share of NICU admissions. Understanding chorionicity lets you predict which pairs are at risk for the transfusion syndromes and plan the delivery-room resources each baby will need.
2. Who This Guideline Applies To
Scope
- Twins and higher-order multiples, with particular attention to monochorionic pregnancies.
- Infants affected by TTTS, twin anemia-polycythemia sequence (TAPS), or selective growth restriction.
- Cross-references: prematurity care (2.x); FGR (13.4); anemia and polycythemia (10.x); hydrops (13.7).
3. Chorionicity — The Key Determinant
| Type | Placenta / sacs | Key risks |
|---|
| Dichorionic-diamniotic | Two placentas, two sacs | Lowest shared-circulation risk; still prematurity/FGR |
| Monochorionic-diamniotic | One placenta, two sacs | TTTS, TAPS, selective FGR (shared anastomoses) |
| Monochorionic-monoamniotic | One placenta, one sac | All of the above plus cord entanglement |
Remember
Chorionicity is best determined by early ultrasound. Monochorionic pregnancies need closer surveillance precisely because of their shared placental vasculature.
4. Twin–Twin Transfusion Syndrome (TTTS)
In TTTS, unbalanced arteriovenous anastomoses across a shared monochorionic placenta shunt blood from one twin (the donor) to the other (the recipient). The result is two opposite clinical pictures from a single placenta.
| Donor twin | Recipient twin |
|---|
| Volume status | Hypovolemic | Hypervolemic |
| Amniotic fluid | Oligohydramnios ("stuck twin") | Polyhydramnios |
| Hematology | Anemia | Polycythemia / hyperviscosity |
| Growth | Growth restriction | Often larger |
| Cardiac | Underfilled | Volume overload, cardiomyopathy, hydrops |
Antenatal Treatment
Severity is described by Quintero staging. Fetoscopic laser photocoagulation of the connecting placental vessels is the preferred treatment for advanced TTTS, interrupting the shared circulation; amnioreduction is an alternative in some settings.
5. Related Monochorionic Complications
Beyond Classic TTTS
- TAPS (twin anemia-polycythemia sequence): large inter-twin hemoglobin difference without the amniotic-fluid discordance of TTTS — one twin anemic, one polycythemic.
- Selective FGR: unequal placental sharing producing one growth-restricted twin.
- Twin reversed arterial perfusion (TRAP): an acardiac twin perfused by the pump twin.
- Single fetal demise in monochorionic pairs: risk of acute hypotension/injury in the survivor through the shared circulation.
6. Neonatal Presentation
At the Bedside
- Donor: small, pale/anemic, may be hypovolemic and growth-restricted.
- Recipient: larger, plethoric, at risk of hyperviscosity, hyperbilirubinemia, and signs of volume overload or cardiomyopathy.
- Both are frequently preterm from early delivery.
7. Recommended Workup
What to Check
- Hematocrit on each twin — anemia in the donor, polycythemia in the recipient.
- Glucose and temperature per prematurity/FGR protocols.
- Bilirubin — the polycythemic recipient is prone to significant jaundice.
- Cardiac assessment/echo in the recipient if volume overload, cardiomyopathy, or hydrops is suspected.
8. Delivery-Room Plan
1
Prepare per baby
One resuscitation team and warmer per infant; know chorionicity and any TTTS/TAPS diagnosis in advance.
2
Resuscitate and identify
Standard NRP; clearly label donor vs recipient; anticipate the anemic and the plethoric baby.
3
Check hematocrits early
Treat symptomatic anemia in the donor and symptomatic polycythemia in the recipient per thresholds.
4
Support and monitor
Glucose, temperature, bilirubin; cardiac support for the volume-overloaded recipient as needed.
9. Management of the Associated Problems
| Problem | Approach |
|---|
| Donor anemia | Transfusion for symptomatic or severe anemia; monitor. |
| Recipient polycythemia | Hydration; partial exchange transfusion only if symptomatic and very high hematocrit. |
| Recipient volume overload / cardiomyopathy | Supportive cardiac care; cardiology input if hydrops or dysfunction. |
| Hyperbilirubinemia | Phototherapy on the nomogram (higher loads in the polycythemic recipient). |
| Prematurity / FGR | Standard preterm and growth-restriction care. |
10. Monitoring
What to Track
- Serial hematocrit and bilirubin in both twins.
- Glucose, temperature, and growth.
- Cardiac status in the recipient until resolved.
- Neurologic surveillance — monochorionic twins (especially after single demise or severe TTTS) carry higher neurodevelopmental risk.
11. Contraindications & Precautions
Safety Cautions
- Do not assume both twins have the same problem — donor and recipient are physiologic opposites.
- Do not overlook TAPS just because amniotic-fluid discordance is absent — check hemoglobins.
- Do not perform partial exchange for an asymptomatic, borderline hematocrit.
- Do not underestimate the neurologic risk to the survivor after co-twin demise in monochorionic pairs.
12. Escalation & Follow-Up
Escalate When…
- Recipient cardiac dysfunction, hydrops, or severe polycythemia.
- Severe donor anemia or hemodynamic instability.
- Neurologic concern, particularly after severe TTTS or co-twin demise.
Discharge & Follow-Up
- Stable hematology, resolved cardiac issues, feeding established.
- Neurodevelopmental follow-up for monochorionic and TTTS-affected infants.
Parent Counselling Points
- "Because your twins shared one placenta, blood flow between them was uneven — that's why one baby is smaller and one is bigger, and we treat each differently."
- "We check blood counts on both babies and support each one's specific needs."
- "We'll arrange developmental follow-up, which is routine for twins who shared a placenta."
13. Key Pearls
High-Value Clinical Pearls
- Chorionicity drives risk — monochorionic twins share vessels and get TTTS/TAPS.
- TTTS = donor (small, anemic, oligohydramnios) vs recipient (large, plethoric, polyhydramnios, volume-overloaded).
- Fetoscopic laser photocoagulation is the treatment of choice for advanced TTTS; Quintero staging grades severity.
- TAPS = hemoglobin discordance without fluid discordance.
- Co-twin demise in a monochorionic pair threatens the survivor's brain through the shared circulation.
14. Common Mistakes to Avoid
Pitfalls & Better Practice
The recurring errors when managing twins and TTTS.
| Mistake | Why it harms | Better practice |
|---|
| Treating both twins identically. | Donor and recipient are opposites. | Individualize — check each baby's hematocrit and volume status. |
| Missing TAPS. | No fluid discordance to tip you off. | Compare hemoglobins in monochorionic twins. |
| Under-resourcing the delivery. | Both babies may need resuscitation. | A full team and warmer per infant. |
| Ignoring survivor risk after co-twin demise. | Shared circulation causes injury. | Heightened neurologic surveillance. |
15. Board-Style High-Yield Summary
Key Takeaways
- Chorionicity determines risk; monochorionic twins share placental anastomoses.
- TTTS: donor (anemic, oligohydramnios, growth-restricted) and recipient (polycythemic, polyhydramnios, volume overload/hydrops).
- Quintero staging guides management; fetoscopic laser photocoagulation is preferred for advanced disease.
- TAPS = hemoglobin discordance without fluid discordance.
- Prepare separate resuscitation for each infant; monoamniotic twins also risk cord entanglement.
- Monochorionic pairs carry higher neurodevelopmental risk, especially after single demise.
16. References
- 1.Society for Maternal-Fetal Medicine. Twin-twin transfusion syndrome.
- 2.Simpson LL. Twin-twin transfusion syndrome. Am J Obstet Gynecol. 2013;208(1):3–18.
- 3.Quintero RA, et al. Staging of twin-twin transfusion syndrome. J Perinatol. 1999.
- 4.Baylor College of Medicine, Division of Neonatology. Guidelines for Acute Care of the Neonate, Edition 33, 2025–2026.
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