Pregnant women with MG at higher risk of complications: Review study

Disease-related complications can put mother, fetus in danger, researchers say

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by Andrea Lobo |

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Pregnant women with myasthenia gravis (MG) are particularly susceptible to severe disease-related complications, usually caused by generalized muscle weakness, which can put the mother and child at risk, according to a recent review study.

Newborns should also be monitored for symptoms of transient neonatal MG, a form of the disease caused by self-antibodies passed from the mother to baby through the placenta during pregnancy, researchers note.

“Given that this condition mainly affects fertile women, it is imperative to be knowledgeable about MG and the interdisciplinary diagnostic and therapeutic care it requires,” they wrote.

The review study, “Choices and Challenges With Treatment of Myasthenia Gravis in Pregnancy: A Systematic Review,” was published in the journal Cureus.

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MG is a neuromuscular disease characterized by muscle weakness and fatigue. It is usually caused by self-reactive antibodies that attack proteins involved in nerve-muscle communication, most commonly acetylcholine receptors.

The disease can affect any muscles involved in the body’s voluntary movements, including those controlling eye and limb movements, and breathing.

Although MG affects both men and women and can arise at any age, women are most commonly affected, often during their third decade of life.

Myasthenia gravis may worsen during pregnancy

The disease can also worsen during pregnancy, leading to complications for both mothers and their newborns.

To further explore the effects of MG on women during pregnancy and on newborns, a team led by researchers in Indonesia conducted a systematic review analysis of the literature.

The review included 40 studies conducted in various countries, published since 2000, which collected data from 1,322 women with MG and a total of 1,604 pregnancies from 1967 to 2022.  Nineteen were retrospective studies, 16 were reviews, and the remaining were other types of studies.

The mean age of the mothers ranged from 25.8 to 48.1 years. Although most babies were born by vaginal birth, a significant number of babies were born by cesarean section.

“In cases of severe myasthenia or respiratory compromise, a cesarean section may be recommended to avoid excessive stress on the respiratory system,” the researchers wrote.

A total of 401 exacerbations (episodes of disease worsening) were reported across the 16 studies analyzing the course of MG during pregnancy. Disease worsening occurred in 35.1% of the analyzed women, while improvement was observed in 8.8% of the cases.

Complications were also reported during pregnancy in some studies. These included spontaneous abortions, myasthenic crisis, preterm birth, and preterm premature rupture of membranes (PPROM) — a pregnancy complication in which the sac surrounding the baby, called the amniotic membrane, breaks prematurely.

“In contrast to the 3% risk in the general population, PPROM appears more common in women with MG, which affects 6.7% of all pregnancies,” the researchers wrote.

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Transient neonatal MG occurs in 10%-20% of babies born to mothers with MG

Newborns also experienced complications, which included the development of transient neonatal MG, a condition that can occur in 10%-20% of babies born to mothers with MG. Babies with the condition often recover naturally as maternal autoantibodies gradually disappear on their own.

Other complications included Down syndrome, yellowish pigmentation of the skin, and erythroblastosis, a type of anemia in which the red blood cells of a fetus are destroyed by the mother’s immune system.

Most women with MG were being treated with medications that included corticosteroids like prednisone, pyridostigmine (sold as Mestinon), and rituximab. Immunosuppressants like cyclosporine, azathioprine, and methotrexate were also used, as was intravenous immunoglobulin therapy.

The percentage of women who underwent a thymectomy, which is a surgery to remove the thymus gland, before pregnancy ranged from 16% to 100% among the analyzed studies.

“Studies suggest that thymectomy can lead to disease remission or improvement in a significant number of patients, potentially reducing the need for long-term immunosuppressive medications during pregnancy,” the researchers wrote. “However, the timing of thymectomy should be carefully considered to optimize the benefits and minimize risks to both the mother and the fetus.”

“MG is a condition that has a high risk of complications, especially when a woman is pregnant,” the researchers concluded. “Severe illnesses that may even be life-threatening, such as respiratory insufficiency that puts both the expectant mother and the unborn child in danger, may occur, especially due to generalized weakness.”