Rare cases of LEMS in pregnancy show need for personalized care
Study highlights challenge of balancing seizure prevention with safety concerns
Managing Lambert-Eaton Myasthenic syndrome (LEMS) during pregnancy can be challenging, especially when high blood pressure conditions like preeclampsia are involved, a review paper highlights.
Magnesium sulfate is the standard treatment used to prevent seizures associated with preeclampsia, but it can worsen muscle weakness in people with LEMS and raise the risk of breathing problems.
Available literature — which was scarce — showed magnesium sulfate was rarely used in reported LEMS cases during pregnancy, and only a few studies described alternative treatment options.
“Findings emphasized the rarity of LEMS in pregnancy and the limited guidance surrounding management of preeclampsia in this population,” the researchers wrote. “Further research is needed to establish safe, evidence-based guidelines for managing this rare but high-risk patient population.”
The review study, “The management of Lambert Eaton syndrome in the setting of hypertensive disorders of pregnancy: A literature review,” was published in Pregnancy Hypertension.
Understanding LEMS and why pregnancy adds extra challenges
LEMS is an autoimmune disease marked by self-reactive antibodies that interfere with the communication between nerve and muscle cells, leading to muscle weakness and other symptoms.
“Given the potential for LEMS to affect women during their peak reproductive years (particularly in the second and third decades of life), understanding its implications during pregnancy is clinically important,” the researchers wrote. However, “the [frequency] of maternal LEMS remains unknown due to its extreme rarity.”
Reports of pregnancy in women with LEMS are rare, and even fewer describe how it should be managed — especially when high blood pressure conditions like preeclampsia or eclampsia are involved, since their standard treatment, magnesium sulfate, can worsen LEMS symptoms.
Preeclampsia is a serious pregnancy complication that causes new and persistent high blood pressure, or hypertension, and is often linked to excess protein in urine, a sign of kidney problems. Eclampsia refers to seizures that can occur when preeclampsia is not controlled.
Here, a team of U.S. scientists combed through the scientific literature published through May 2024 to find studies describing pregnancies affected by LEMS or related conditions.
A total of 24 studies were included, and 25% were case reports. More than one-quarter of the studies (29%) involved pregnancies complicated by myasthenia gravis (MG), an autoimmune disease that also affects the nerve-muscle connection and is more common than LEMS. Less than one-quarter (21%) described pregnancies complicated by LEMS.
Little data leaves big questions about LEMS in pregnancy
The scientists highlighted that there is very little data on LEMS and pregnancy, making it difficult to draw far-reaching conclusions and underscoring the need for more research. They noted that problems in babies born to women with LEMS were “rarely observed but require close monitoring.”
Two cases involved both LEMS and preeclampsia. One woman had been diagnosed with LEMS before pregnancy, and magnesium sulfate was used in one case — not for preeclampsia, but for preterm labor (before 37 weeks of gestation).
The use of magnesium sulfate was discussed in two other studies, one involving a MG patient. Two studies (8%) described alternative approaches to treating preeclampsia.
“Magnesium sulfate, though widely used for seizure [prevention in preeclampsia], was rarely administered in reported LEMS or MG cases due to safety concerns,” the researchers wrote, adding that “the need for individualized, multidisciplinary management was a consistent recommendation.”
“LEMS with [high blood pressure] disorders in pregnancy is complex, rare, and underreported,” the team wrote.
They emphasized more research is needed to determine the best way to manage LEMS when preeclampsia occurs, and that clinicians must use their best judgement to tailor personalized care in these rare cases.
“Ultimately, careful [planning around childbirth], early identification of at-risk patients, and avoidance of neuromuscular-compromising drugs are central to safe obstetric care in this population,” the researchers wrote.
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