Pregnancy in women with spinal muscular atrophy (SMA): maternal and neonatal outcomes with multi-speciality management

Spinal muscular atrophy (SMA) is a rare inherited disorder that results in skeletal muscle wasting and weakness with a varying degree of severity. Pregnancy is associated with several changes in respiratory muscle function and respiratory physiology, which can compromise breathing leading to complications during pregnancy and delivery. Pregnant women with SMA are therefore considered to be a high-risk obstetric group. Due to the rare nature of the condition, it is infrequently encountered in pregnancy and this highlights the clinical importance of reporting this current case series. We report, in this retrospective case series, the outcomes of eight pregnancies in six women living with SMA, including, to our knowledge, the first reported successful pregnancy in a woman with SMA type-1, managed in our tertiary multi-professional and multi-speciality centre. All pregnancies, over an 18-year period, resulted in healthy live births between 30 and 39 weeks of gestation, six were pre-term (before 37 weeks gestation) and two were term. Although there were no maternal deaths, four women had a deterioration in respiratory function during the second trimester. All, but one returned to their pre-pregnancy state by three months postpartum. One had an obstetric-related post-partum complication and returned to pre-pregnancy baseline by the first year postpartum. Our case series, of a rare neuromuscular condition in pregnancy, strongly supports that appropriate multi-professional and multi-speciality care for pregnant women living with SMA enhances the outcome for both mother and baby. Indeed, two of our women had the confidence to proceed with a second pregnancy, both of which concluded in good outcomes.