Lymphatic malformations (LM) and some complex lymphatic anomalies (CLA) are identified during pregnancy, while others are diagnosed shortly after delivery.
Most LMs grow proportionally with the fetus. In some cases, they may decrease in size or (rarely) resolve depending on the underlying cause.
A prenatal diagnosis can feel overwhelming. Every pregnancy is different, and outcomes vary widely depending on the size, location, and underlying cause of the condition.
Prenatal Diagnosis
LMs are often detected during routine prenatal care.
Routine Ultrasound
Lymphatic malformations can be first identified between 9 and 16 weeks of pregnancy. They may appear as fluid-filled cysts on ultrasound.
Fetal MRI
Fetal MRI provides more detailed imaging to evaluate the size, location, and potential impact on nearby structures such as the airway, lungs, or heart.
Genetic Evaluation
In some cases, additional testing may be recommended, including:
- Amniocentesis
- Chorionic villus sampling (CVS)
Certain chromosomal or genetic conditions may be associated with lymphatic malformations, including:
- Trisomy 21 (Down syndrome)
- Turner syndrome
- Noonan syndrome
Fetal Echocardiography
A fetal echocardiogram may be performed to assess heart structure and function.
Monitoring During Pregnancy
When a lymphatic malformation or fluid complication is identified, ongoing monitoring is typically recommended.
This may include:
- Serial ultrasounds to track growth and fluid levels
- Fetal MRI in selected cases
- Fetal echocardiography
- Genetic consultation when indicated
- Referral to a maternal-fetal medicine specialist or fetal care center
Many pregnancies are managed with careful observation alone.
In Utero Treatment
In certain high-risk situations — particularly when fluid accumulation is severe or causing strain on the lungs or heart — fetal intervention may be considered at specialized centers.
Possible in-utero treatments include:
- Ultrasound-Guided Drainage: Temporary removal of fluid from the fetal chest to relieve pressure.
- Thoracoamniotic Shunt Placement: Placement of a small tube that allows continuous drainage of chest fluid into the amniotic sac.
Maternal Medication Therapy
In rare and carefully selected cases, medications such as mTOR inhibitors (sirolimus) have been used under specialist supervision. These approaches are individualized and managed by experienced fetal therapy teams.
Not all cases require intervention. Decisions are highly individualized based on:
- Severity
- Gestational age
- Underlying diagnosis
- Overall fetal stability
Delivery Planning
Delivery planning is coordinated by a multidisciplinary team that may include:
- Maternal-fetal medicine specialists
- Neonatologists
- Pediatric surgeons
- Anesthesiologists
In rare cases where airway compromise is expected, an EXIT (Ex-Utero Intrapartum Treatment) procedure may be performed. This allows the baby’s airway to be secured while still supported by the placenta.
After Birth
After delivery, newborns may require:
- Respiratory support
- Imaging (ultrasound or MRI)
- Chest tube drainage if pleural effusion is present
- Nutritional management for chylothorax
- Medication therapy
- Ongoing monitoring
Some infants require care in a neonatal intensive care unit (NICU), while others may only need observation.
Treatment depends on the underlying diagnosis and the baby’s overall health.
Emotional Support During Pregnancy
Receiving a prenatal diagnosis can bring uncertainty and fear. It is important to remember:
- Lymphatic malformations are developmental conditions.
- They are not caused by anything a parent did.
- Outcomes vary widely.
- Many children go on to live full and meaningful lives.
