The Healthcare cost and utilization project, nationwide inpatient sample (HCUP-NIS) database includes information on more than 7 million hospital stays in the United States each year. A Canadian team used it to conduct a retrospective cohort study (2005 – 2015) of nearly 10 million deliveries, including 974 women with myasthenia gravis. This disease of the neuromuscular junction begins more often in adults, before the age of 40, predominantly female (about two thirds of cases).
Arguments in favor of expert center monitoring
The Canadian study shows, in pregnant women with myasthenia gravis compared to those without the disease:
- more frequent comorbidities (obesity, diabetes, hypothyroidism, rheumatoid arthritis, etc.), partly linked to the (known) association of myasthenia gravis and other autoimmune diseases,
- an older age: 35 years past in 21.36% of cases, against 15.77% in the absence of myasthenia gravis,
- an absence of increased risk of cesarean section, instrumental childbirth aids and premature rupture of membranes,
- an increased risk of premature birth (10.27% versus 6.38%), and acute maternal respiratory failure (2.26% versus 0.10%) in connection with the possible exacerbation of the disease, especially after childbirth ,
- a longer hospital stay, greater than 3 days in a third of cases (vs 14.53%).
This large-scale study argues in favor of follow-up “in a specialized obstetrical environment, class 3 maternity hospital, and in a reference center for neuromuscular pathology” as recommended in France by the National Diagnostic and Care Protocol (PNDS) on myasthenia gravis, published in 2015.
A recommendation supported by a second publication
Another team of Canadian obstetricians more recently conducted a systematic review of the literature on the subject, and added data from their own follow-up of pregnant women with myasthenia gravis. Out of 824 pregnancies, their analysis found :
- an exacerbation of myasthenia in 1/3 of cases,
- a risk of myasthenic crisis of 6.4% during pregnancy and 8.2% after delivery,
- transient neonatal myasthenia in 13% of cases.
