Pregnancy and breastfeeding in multiple sclerosis (MS), NMOSD, MOGAD, myasthenia gravis and CIDP

For most people with autoimmune diseases of the nervous system, pregnancy and breastfeeding are possible and safe if they are carefully planned. The key is to understand how each disease behaves during pregnancy, which medicines are safe, which are strictly contraindicated, and when it is better to restart treatment after delivery.

On this page we will discuss multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), myasthenia gravis (MG) and chronic inflammatory demyelinating polyneuropathy (CIDP). We will also touch upon the impact of therapy on conception in men (sperm).

Why early consultation is so important

For autoimmune neurological diseases, unplanned pregnancy often coincides with active disease or with the use of medicines that can harm the baby. On the other hand, stopping effective therapy “just in case” may lead to a severe relapse.

Ideally, consultation with a neurologist and gynecologist should take place 6–12 months before the planned conception. During this visit you can:

• Evaluate the current activity of the disease and disability level.
• Discuss which medicines must be stopped in advance and for how long.
• Choose a safer therapy for pregnancy or a “bridge” treatment.
• Plan monitoring during pregnancy and the first year after delivery.
• Discuss breastfeeding and the timing of treatment restart.
• For men – clarify whether current therapy can affect sperm and fertility.

Multiple sclerosis and pregnancy

How pregnancy affects MS

In most women with MS, pregnancy is accompanied by a natural decrease in relapse rate, especially in the third trimester. This is due to the immune system becoming more “tolerant” to support the baby. However, during the first 3–6 months after delivery, the relapse risk increases again, and for some women it may exceed the pre-pregnancy level.

Most women with MS can have healthy pregnancies and healthy children. The main task is to enter pregnancy with well-controlled disease and to avoid abrupt discontinuation of effective medicines.

Which MS medicines are considered safer

Please note: the information below is general. The final decision must always be made by you and your neurologist on an individual basis.

• Interferon-β and glatiramer acetate are considered relatively safe during pregnancy. They can often be continued until conception and, in some cases, throughout pregnancy and breastfeeding.
• Natalizumab may be continued (often with extended dosing intervals) in women with very active disease, when the risk of severe relapse is higher than the potential risks to the baby.
• Anti-CD20 antibodies (ocrelizumab, rituximab) are usually given as an infusion some months before conception to “cover” the pregnancy period, and then paused. In some situations they may be used closer to conception with individual risk assessment.

Teratogenic medicines that must be avoided

Some MS medicines are teratogenic – they can cause congenital malformations or affect fetal development. It is extremely important not to become pregnant while taking them and to observe the recommended wash-out periods:

• Teriflunomide – must be stopped well before conception. If pregnancy occurs, accelerated elimination therapy is required. Teriflunomide is also excreted in semen, therefore for men planning conception it is recommended to either stop the drug with elimination procedure or use reliable contraception.
• S1P receptor modulators (fingolimod – the first drug in this group, as well as siponimod, ozanimod, ponesimod) – are contraindicated in pregnancy due to an increased risk of congenital malformations. Before conception, a wash-out period is required; the exact duration depends on the specific medicine and must be discussed with your neurologist.
• Cladribine – pregnancy should be avoided during the treatment course and for a significant period afterwards, for both women and men, due to potential effects on rapidly dividing cells.
• Alemtuzumab – due to its long-lasting effects on the immune system and potential impact on the thyroid gland, pregnancy is usually not recommended for at least 4 months after the last infusion. For many patients, an even longer interval is chosen to ensure stable disease control and endocrine balance.

Stopping high-efficacy therapy such as S1P modulators, natalizumab or some other medicines can lead to a rebound of disease activity. Therefore, the timing of discontinuation and the choice of alternative treatment (“bridge therapy”) should always be planned in advance.

NMOSD (neuromyelitis optica spectrum disorder) and pregnancy

In NMOSD, attacks tend to be more severe than in typical MS and may lead to significant visual or motor disability. Therefore, maintaining stable remission during pregnancy is especially important.

In many women, relapse rates may decrease during pregnancy, but there is a significant increase in relapses in the postpartum period, especially in patients with AQP4-IgG–positive NMOSD. NMOSD is also associated with a higher risk of miscarriage, preeclampsia and other obstetric complications, so close cooperation between the neurologist and obstetrician is essential.

Treatment during pregnancy

• Azathioprine can often be continued during pregnancy. It has been used for many years in other autoimmune diseases and in pregnant transplant recipients.
• Rituximab is usually given before conception to reduce relapse risk and then paused. In individual high-risk cases, it may be used during pregnancy with careful monitoring.
• Prednisone/prednisolone at the lowest effective dose can be used when necessary.

Newer NMOSD medicines (for example, eculizumab, inebilizumab, satralizumab) have limited pregnancy data, so decisions on their use are made individually in referral centers.

MOGAD and pregnancy

For patients with MOG antibody-associated disease (MOGAD), available data suggest that most pregnancies are uncomplicated. Relapse risk is usually low during pregnancy and only slightly increased postpartum. However, in patients with a history of frequent attacks, postpartum relapses can still occur.

Long-term maintenance therapy (for example, with azathioprine, mycophenolate, IVIG or anti-CD20 antibodies) may be modified or temporarily stopped before conception, depending on disease activity and the safety profile of each drug. Evidence is still limited, and prospective studies are ongoing, so MOGAD patients planning pregnancy are usually followed in specialized centers.

Myasthenia gravis and pregnancy

In myasthenia gravis (MG), pregnancy can proceed quite safely, although mild worsening of symptoms is possible, especially in the first trimester and in the early postpartum period. Careful planning reduces the risk of exacerbations.

MG medicines during pregnancy

• Pyridostigmine is usually safe and remains the basic symptomatic treatment.
• Corticosteroids (prednisone/prednisolone) can be used when necessary, aiming for the lowest effective dose.
• Azathioprine is generally acceptable during pregnancy when benefits outweigh risks.
• Mycophenolate mofetil, methotrexate and cyclophosphamide are strictly contraindicated in pregnancy due to teratogenicity and must be stopped well in advance.
• IVIG (intravenous immunoglobulin) and plasma exchange are considered safe options for treating exacerbations or preparing for delivery.

About 10 % of newborns of mothers with MG develop transient neonatal myasthenia due to the transfer of maternal antibodies through the placenta. Symptoms usually appear within the first days of life (weak sucking, hypotonia, breathing difficulties) and require observation in a maternity hospital or neonatal unit. In most cases, they resolve within a few weeks.

CIDP and pregnancy

Data on chronic inflammatory demyelinating polyneuropathy (CIDP) and pregnancy are more limited than for MS or MG, but overall experience is reassuring. Many women with stable CIDP have uneventful pregnancies.

• IVIG is considered the safest long-term therapy during pregnancy and can usually be continued.
• Corticosteroids may be used when needed, especially in the first trimester, with careful monitoring.
• Other immunosuppressive drugs (azathioprine, cyclosporine, etc.) are chosen individually, with preference for agents with more pregnancy safety data.

Medicines and conception: women and men (sperm)

Women planning pregnancy

For women, the key questions are: when to stop a medicine, whether a wash-out is needed, and whether a safer alternative is required. As mentioned above, teriflunomide, S1P modulators (fingolimod and others), cladribine, mycophenolate, methotrexate and cyclophosphamide are teratogenic or potentially dangerous and require special planning.

Men, therapy and sperm

For men with autoimmune neurological diseases, it is also important to consider the impact of treatment on sperm quality and fertility.

• Teriflunomide is excreted in semen. Men taking teriflunomide who wish to conceive are usually advised to either undergo accelerated elimination of the drug or to use reliable contraception until the medicine is cleared from the body.
• Cyclophosphamide and some other cytotoxic drugs may reduce sperm count and damage fertility. In many cases, sperm banking before treatment is discussed.
• For interferons, glatiramer acetate, natalizumab and anti-CD20 antibodies, available data do not show a significant negative effect on male fertility, but high-quality studies are still limited.

If you are a male patient planning fatherhood, it is worth discussing your current and future therapy with a neurologist and, if needed, with an andrologist.

Which treatments can be continued during pregnancy

In clinical practice, doctors balance two risks: the risk of relapse for the mother and the potential effect of the medicine on the baby. In patients with mild disease, it is sometimes possible to pause therapy; in highly active disease, continuing certain medicines during pregnancy may be the safest option overall.

Examples of medicines that are often used (with individual assessment):

• MS: interferon-β, glatiramer acetate, natalizumab in highly active disease, anti-CD20 therapy given before conception.
• NMOSD/MOGAD: azathioprine, low-dose corticosteroids, anti-CD20 therapy given before conception.
• MG: pyridostigmine, azathioprine, corticosteroids; IVIG and plasma exchange for exacerbations.
• CIDP: IVIG, corticosteroids.

Acute relapses during pregnancy are usually treated with high-dose intravenous steroids. In severe NMOSD attacks or in MG crises, plasma exchange or IVIG may be used.

Breastfeeding, relapse risk and when to restart therapy

Breastfeeding is important not only for the baby but also for the mother. For women with MS, several studies have shown that exclusive breastfeeding (without formula supplements) for at least 2–4 months is associated with a lower relapse risk in the first postpartum year and may have a neuroprotective effect on long-term disease course.

However, if the disease is very active or if there has been a severe relapse shortly before pregnancy or during pregnancy, early restart of high-efficacy therapy may be more important than prolonged breastfeeding. This is always an individual decision, which we discuss openly with each patient.

Which medicines are compatible with breastfeeding?

Many modern recommendations allow the use of certain medicines during breastfeeding (again, with individual counseling):

• Interferon-β and glatiramer acetate – very low levels are found in breast milk; they are generally considered compatible with breastfeeding.
• Anti-CD20 antibodies (ocrelizumab, rituximab) – large molecules with minimal transfer into breast milk and low absorption from the infant gut. Many experts allow breastfeeding after infusion, with monitoring of the baby.
• Natalizumab – may be used during breastfeeding in selected cases, especially if the mother’s disease is highly active.
• Azathioprine – often considered compatible with breastfeeding; the dose received by the infant through milk is low.
• Prednisone/prednisolone – small amounts pass into breast milk. Sometimes mothers are advised to feed the baby just before taking the tablet or to wait several hours after a high dose.
• Pyridostigmine – considered compatible with breastfeeding in MG.

Teriflunomide, S1P modulators, cladribine, mycophenolate, methotrexate and cyclophosphamide are not recommended during breastfeeding.

When to restart therapy after delivery?

There is no single rule suitable for everyone. The timing of therapy restart depends on:

• How active the disease was before pregnancy.
• Whether there were relapses during pregnancy.
• Which medicine you plan to restart.
• Whether you want to breastfeed exclusively and for how long.

For some women with low disease activity, it is acceptable to breastfeed exclusively for 3–6 months and then restart therapy. For others, especially with highly active MS or NMOSD, therapy is restarted much earlier, sometimes within the first weeks after delivery, while maintaining breastfeeding on compatible medicines.

Delivery, anesthesia and when to seek urgent help

In most cases, vaginal delivery is possible. The choice between vaginal delivery and cesarean section is determined by obstetric indications rather than by MS, NMOSD, MOGAD, MG or CIDP alone. Epidural or spinal anesthesia is usually allowed; the type of anesthesia is chosen jointly by the neurologist and anesthesiologist.

You should seek urgent medical help if:

• New neurological symptoms appear (sudden vision loss, weakness in arms or legs, severe imbalance, loss of sensation, difficulty speaking or swallowing).
• There is a marked worsening of myasthenic symptoms (shortness of breath, difficulty lifting the head, severe chewing or swallowing difficulties).
• You experience severe headache, visual disturbance, high blood pressure or seizures (possible preeclampsia/eclampsia).

Summary table: main medicines, pregnancy and breastfeeding

References

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