Pompe Disease and Pregnancy: What Expecting Mothers and Their Care Teams Need to Know

What Is Pompe Disease?

Pompe disease (also called glycogen storage disease type II or acid maltase deficiency) is a rare inherited metabolic disorder caused by a deficiency of the enzyme acid alpha-glucosidase (GAA). Without sufficient GAA, glycogen accumulates in lysosomes throughout the body — particularly in muscle cells — causing progressive muscle weakness.

The condition exists on a spectrum:

• Classic infantile-onset Pompe: Severe, presents within the first year of life with profound muscle weakness and cardiomegaly. Without treatment, it is typically fatal within the first year
• Late-onset Pompe (LOPD): Slower progression, primarily affects skeletal and respiratory muscles, can present in childhood through adulthood

For women of reproductive age, late-onset Pompe is the relevant form. According to the National Organization for Rare Disorders (NORD), the overall prevalence of Pompe disease is estimated at approximately 1 in 40,000 births, though this varies by population.

How Pompe Disease Affects Pregnancy

Pregnancy creates significant physiological demands that can interact with the underlying muscle weakness of Pompe disease in important ways.

Respiratory Function

The most critical concern in Pompe disease during pregnancy is respiratory compromise. The diaphragm and accessory respiratory muscles are often affected in LOPD. As pregnancy progresses:

• The growing uterus elevates the diaphragm, reducing functional residual capacity
• Oxygen demand increases by approximately 20% during pregnancy
• The combination of pre-existing respiratory muscle weakness and pregnancy-related mechanical changes can significantly reduce respiratory reserve

Women with Pompe disease should have baseline pulmonary function testing (PFTs) before conception and regular monitoring throughout pregnancy. Forced vital capacity (FVC) below 50% of predicted is associated with higher respiratory risk during pregnancy and delivery.

Musculoskeletal Changes

Pregnancy hormones — particularly relaxin — increase joint laxity throughout the body. For women with Pompe disease who already have compromised proximal muscle strength, this can:

• Increase fall risk
• Worsen mobility limitations
• Make activities of daily living more challenging in the third trimester

Cardiac Considerations

While cardiac involvement is primarily a feature of classic infantile Pompe, some adults with LOPD have subclinical cardiac changes. Echocardiographic assessment before and during pregnancy is recommended for women with any cardiac history related to their condition.

Enzyme Replacement Therapy (ERT) During Pregnancy

Alglucosidase alfa (Myozyme/Lumizyme) is the standard enzyme replacement therapy for Pompe disease. The question of whether to continue ERT during pregnancy is one of the most important clinical decisions for affected women.

What the Evidence Shows

Data on ERT use during pregnancy is limited to case reports and small case series, as randomized controlled trials in pregnant populations are not feasible for rare diseases. Published cases suggest:

• ERT has been continued throughout pregnancy in multiple reported cases without apparent fetal harm
• Discontinuing ERT during pregnancy carries the risk of disease progression and respiratory decline
• The manufacturer classifies alglucosidase alfa as Pregnancy Category B (animal studies show no fetal risk; adequate human studies are lacking)

The European Working Group on Pompe Disease and most metabolic disease specialists generally recommend continuing ERT during pregnancy given the risks of discontinuation, while acknowledging the limited evidence base.

Infusion Reactions

Women with Pompe disease on ERT may experience infusion-associated reactions. During pregnancy, the management of these reactions (which may involve antihistamines, corticosteroids, or epinephrine in severe cases) requires careful consideration of fetal effects. Infusions should be administered in settings equipped to manage reactions.

Preconception Planning

For women with Pompe disease considering pregnancy, preconception planning with a multidisciplinary team is essential. This team should ideally include:

• Metabolic disease specialist or neurologist with Pompe expertise
• Maternal-fetal medicine (MFM) specialist (high-risk obstetrician)
• Pulmonologist for respiratory assessment
• Physical therapist familiar with neuromuscular conditions
• Genetic counselor to discuss inheritance patterns

Genetic Counseling

Pompe disease is inherited in an autosomal recessive pattern. This means:

• Both parents must carry a GAA mutation for a child to be affected
• If one parent has Pompe disease, all children will be carriers
• If the other parent is also a carrier (approximately 1 in 100–200 in the general population), each pregnancy has a 50% chance of producing a carrier and a 25% chance of an affected child

Carrier testing for the partner and discussion of prenatal diagnostic options (chorionic villus sampling or amniocentesis) should be part of preconception counseling.

Delivery Planning

Mode of Delivery

Vaginal delivery is generally preferred when possible, as it avoids the additional respiratory demands and recovery challenges of cesarean section. However, the decision must be individualized based on:

• Respiratory reserve (FVC)
• Degree of proximal muscle weakness
• Fetal position and obstetric factors

Women with significantly compromised respiratory function may require cesarean delivery to avoid the prolonged respiratory demands of active labor.

Anesthesia Considerations

Regional anesthesia (epidural or spinal) is generally preferred over general anesthesia in Pompe disease, as general anesthesia carries higher respiratory risks in patients with muscle weakness. The anesthesia team should be briefed on the diagnosis well in advance of delivery.

Postpartum Monitoring

The postpartum period carries its own risks. Respiratory function should be monitored closely in the immediate postpartum period. Women who discontinued or modified ERT during pregnancy should discuss resumption with their metabolic specialist.

Breastfeeding

Limited data exists on ERT excretion in breast milk. Given the large molecular size of alglucosidase alfa, significant transfer to breast milk is considered unlikely, but this has not been formally studied. Women should discuss the decision to breastfeed with their care team, weighing the benefits of breastfeeding against the uncertainties of ERT exposure.

Finding Support

Living with a rare disease during pregnancy can be isolating. Resources include:

• Acid Maltase Deficiency Association (AMDA): amda-pompe.org
• Muscular Dystrophy Association (MDA): mda.org
• NORD (National Organization for Rare Disorders): rarediseases.org
• Pompe Community (patient forum): pompe.com

*This content is for educational purposes only and does not constitute medical advice. Pompe disease management during pregnancy requires individualized care from a specialized multidisciplinary team. All treatment decisions should be made in consultation with qualified healthcare providers.*