Woman with SMA type 2 gives birth despite breathing problems
Baby was delivered at 28 weeks by C-section
A young woman with spinal muscular atrophy (SMA) type 2 gave birth to a premature baby boy with the help of a multidisciplinary team despite having severe breathing problems, according to a report.
The woman’s shortness of breath got worse during pregnancy and she began using a ventilator more frequently and for longer periods. This led to the baby being delivered at 28 weeks by C-section under general anesthesia.
“Women with SMA and severe restrictive lung disease are at high risk of premature delivery and require a multidisciplinary approach for treatment,” the researchers wrote in “Pregnancy in a Patient with Spinal Muscular Atrophy and Severe Restrictive Lung Disease,” which was published in the American Journal of Perinatology Reports.
SMA is a genetic disease that causes progressive muscle weakness. Giving birth with SMA can be difficult due to atrophy (wasting) and low muscle tone. Preterm (early birth) and C-section are commonly suggested to help deliver a baby safely.
Some women with SMA may also have worsening symptoms during pregnancy. If the muscles that aid breathing become weaker and scoliosis, an abnormal curvature of the spine, becomes more pronounced, it can lead to restrictive lung disease.
Breathing problems develop
Here, researchers describe the case of a 24-year-old woman with SMA type 2 who became pregnant after having a miscarriage the previous year. She had been treated with Spinraza (nusinersen), but had stopped due to limited data regarding using it during pregnancy.
Before being pregnant, the woman was on a motorized wheelchair due to impaired mobility. She also had difficulty swallowing, a weak bladder, and severe restrictive lung disease, requiring noninvasive positive pressure ventilation (NIPPV) to help her breathe.
The woman had had surgery when she was 10 for kyphoscoliosis, a backward and sideways curvature of the spine. She had been using NIPPV with nasal pillows (soft inserts that fit into the nostrils) for 12 years, at least eight hours a night.
When she became pregnant, the woman was underweight, weighing only 35 kg (about 77 pounds). Her lung function progressively deteriorated throughout her pregnancy and she had a faster than normal resting heart rate, called tachycardia.
“A multidisciplinary team was assembled including maternal-fetal medicine (MFM), anesthesiology, neonatology, pulmonology, neurology, cardiology, gastroenterology, nutrition, genetics, and social work,” the researchers wrote.
Besides being on corticosteroids, bronchodilators, which are given to widen the airways, and mucus thinners to help her breathe, the woman was started on metoprolol to lower her heart rate. She also began using a mouthpiece to deliver NIPPV for half the day at least two to three days each week.
She had regular checkups and growth scans during her pregnancy. The baby remained healthy and a C-section was set for 28 weeks of gestation, based on the mother’s breathing status and surgical history.
“While vaginal delivery is not contraindicated for patients with SMA, [C-section] was selected for this patient,” the researchers wrote. The C-section was done under general anesthesia, without complications.
In SMA, “genetic counseling is an essential part of prenatal care,” the researchers wrote. The patient had a comprehensive assessment as part of preconception counseling and early pregnancy evaluation. Her partner underwent SMA carrier screening, which revealed two copies of the SMN1 gene.
SMA is inherited in an autosomal recessive manner, meaning the disease will only develop if both copies of the SMN1 gene (one from each biological parent) carry a mutation.
While the patient had prenatal testing for other genetic conditions, she “declined diagnostic genetic testing,” for SMA.
“In a patient with severe preexisting restrictive disease, it is important to weigh these risks carefully. This case demonstrates the importance of NIPPV in the management of severe restrictive disease to meet the higher demands of pregnancy,” the researchers wrote. “The management of an SMA-affected pregnancy requires the expertise of a multidisciplinary team which is involved earlier in the pregnancy.”
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