When parents of twins are told that one or both babies suffered HIE, the shock is doubled and the planning is more complex. This guide explains how HIE happens in twin pregnancies, twin-specific risks during labor and delivery, what cooling treatment looks like for two babies, and how outcomes are evaluated separately.
Why Twin Pregnancies Carry Higher HIE Risk
Twins are more likely than singletons to be born preterm, to be growth-restricted, and to deliver under complicated circumstances. These factors all raise the baseline risk of birth-related brain injury. Specific contributors include preterm delivery (with immature lungs and brain vulnerability), placental insufficiency in one or both twins, twin-to-twin transfusion syndrome in monochorionic pregnancies, cord entanglement in monoamniotic twins, malpresentation (especially of the second twin), and complicated cesarean or operative deliveries. The combination of these factors explains why HIE is more common in twin births even when individual prenatal care has been excellent.
Twin-to-Twin Transfusion Syndrome (TTTS) and HIE
TTTS occurs in monochorionic twin pregnancies (twins sharing a single placenta) when blood flow becomes unbalanced through shared placental vessels. One twin (the donor) becomes anemic and growth-restricted; the other (the recipient) is overloaded with blood volume. Both twins are at increased risk for HIE: the donor from chronic hypoxia, the recipient from cardiovascular stress. Modern management with fetoscopic laser surgery has improved outcomes substantially, but TTTS remains a significant cause of neonatal brain injury in twin pregnancies. If your twins were affected by TTTS, the clinical picture is shaped both by the original imbalance and by the response to treatment.
Twin deliveries are higher-risk and are governed by specific standards of care. A free legal review can help you understand whether the management of your delivery met those standards.
Cord Entanglement and Monoamniotic Twins
Monoamniotic twins (sharing both a placenta and an amniotic sac) face a high risk of cord entanglement throughout pregnancy. This is one reason monoamniotic twins are typically delivered by scheduled cesarean at around 32 to 34 weeks. When cord entanglement causes acute compression late in pregnancy or during delivery, HIE can result. The cord problem may affect one twin disproportionately depending on which umbilical cord becomes compressed.
The Second Twin and Delivery Complications
The second twin to be born often faces higher risk than the first. Reasons include longer time between delivery of the first twin and the second (which can compromise the second twin’s placental support), malpresentation requiring breech extraction or version, cord prolapse or compression after the membranes rupture, and the need for an emergency cesarean partway through delivery. Many HIE cases in twins involve the second twin specifically. If your second twin developed HIE while the first did not, this is a recognized pattern, not a random event.
Cooling Treatment for One or Both Twins
If a twin meets HIE criteria (acidotic cord gas, low Apgar scores, evidence of encephalopathy on neurological exam), therapeutic hypothermia is offered within the 6-hour window. Twins are eligible individually. If both twins qualify, they can be cooled in adjacent NICU bays. The treatment, monitoring, MRI timing, and follow-up are the same as for singletons. Sometimes only one twin meets criteria while the other does not — in that case the unaffected twin does not need cooling, but both should still receive close neurodevelopmental follow-up because subtle differences may emerge.
Long-Term Outcomes: Each Twin Is Their Own Story
One of the harder realizations for twin parents is that twins can have very different outcomes after HIE. The twin who was more severely affected during delivery may have cerebral palsy, while the other twin develops typically. Or both may be affected to different degrees. The MRI findings, neurological exam, and developmental trajectory are evaluated for each twin individually, and follow-up plans are tailored accordingly. This can be emotionally complex: parents often feel guilt about celebrating one twin’s milestones when the other is struggling, or worry that comparing them is unfair. Most twin-of-HIE parents say it gets easier with time and that connecting with other twin-HIE families helps.
What Parents of Twins With HIE Often Need Next
A working list for the first weeks after diagnosis.
Should the unaffected twin still get developmental follow-up?
Yes. Even when one twin appears unaffected, subtle differences in motor or cognitive development can emerge over the first few years. High-risk infant follow-up clinics typically enroll both twins after a complicated pregnancy. Tracking both children together avoids missing later-emerging issues and provides reassuring documentation if development is on track.
How do twin parents balance celebrating one and grieving for the other?
There is no clean answer. Many twin-HIE parents describe parallel emotional tracks: deep joy at one twin’s milestones alongside grief, fear, or fatigue around the other twin’s challenges. Sharing this with a therapist who knows complicated grief, plus connecting with other twin-HIE parents, helps. The answer is not to suppress either feeling but to make room for both.
We help twin-HIE families coordinate medical follow-up, therapy, and legal options across 38 states.
Related reading for parents
- Grades of HIE: mild, moderate, and severe explained
- HIE cooling treatment: what parents need to know
- HIE MRI results explained: what the findings really mean
- Prematurity and cerebral palsy: why preemies face a higher CP risk
- Legal action after HIE: do you have a case?
Our team helps families in 38 states understand the full clinical picture and what services should be in place. No cost. Answers first.
