If you’re living with spinal muscular atrophy (SMA), you can have a happy and healthy pregnancy, a safe delivery, and a healthy baby.
Advances in SMA treatment mean that people with SMA can choose to start a family. However, SMA is a rare disease, so there isn’t much research on how SMA affects pregnancy.
If you have SMA and are thinking about becoming pregnant, continue reading to learn more about pregnancy while living with SMA.
SMA is a neuromuscular disease that can carry additional risks to you and your baby during pregnancy. High-risk pregnancies can result in complications like miscarriage, stillbirth, and preeclampsia (high blood pressure during pregnancy).
Although there may be additional risks in pregnant people with SMA, studies in the Journal of the Neurological Sciences have found that complications for the mother and baby occur at about the same rate as in those without SMA.
A 2012 study looked at 178 pregnant women with neuromuscular disorders in Germany. Researchers found that the number of miscarriages and high blood pressure in women with neuromuscular disorders was about the same as in the general population. A 2018 review of pregnancy outcomes in women with SMA also found that the incidence (how often they occur) of complications for the mother and baby wasn’t higher in women with SMA than in the general population.
Labor with SMA can be difficult due to muscle fatigue. SMA affects your skeletal muscles — the muscles that connect your bones and allow you to move your body. People with SMA don’t have enough of a protein called the survival motor neuron (SMN) protein. Without this protein, the muscles grow weaker.
If you have weaker muscles, you may need additional help during labor. Cesarean sections (C-sections) are one way to help deliver your baby if you can’t have a safe vaginal delivery. A C-section is a procedure where the baby is delivered through a surgical incision in your abdomen and uterus. Several studies have found that C-sections are more common in people with SMA.
The Centers for Disease Control and Prevention (CDC) notes that in the United States, about 32 percent of all babies are born by C-section. A questionnaire sent to women with SMA in the U.S. found that C-sections were more common in women with SMA, especially for those with SMA type 2. A German study cited in the European Journal of Obstetrics, Gynecology, and Reproductive Biology found that 42.4 percent of women with SMA delivered by C-section.
Preterm labor — when labor starts before 37 weeks of pregnancy — is also more common in women with SMA, per the American College of Obstetricians and Gynecologists. About 10 percent of all babies in the U.S. are born preterm. The German study mentioned above found that 29.4 percent of women with SMA had preterm deliveries.
Many people with SMA experience worsening symptoms during their pregnancy. The International Journal of Neuroscience reported that a 2017 questionnaire of women with SMA in the U.S. found that 74 percent of women reported increased muscle weakness during pregnancy. The study of German women found that about one-third of women with SMA reported worsening symptoms during pregnancy.
Experts think that increased muscle weakness during pregnancy could be caused by weight gain and other changes in your body that occur during pregnancy.
Increased muscle weakness may continue after giving birth because of postpartum depression and hormonal changes. In fact, per the study cited above in the International Journal of Neuroscience, 42 percent of women who answered the 2017 questionnaire experienced muscle weakness that continued after giving birth.
Increased muscle weakness can affect your body in other ways. For example, if the muscles that help you breathe become weaker, it can make breathing more difficult. During pregnancy, your lungs need to work harder, whether or not you have SMA. If you have SMA, it’s important to understand how well your lungs are working before and during your pregnancy. It’s still possible to have a successful pregnancy with lower lung function, but the risk of complications like miscarriage and stillbirth is higher.
SMA can be diagnosed through genetic testing. Most babies will be screened for SMA when they’re born, but you may choose to test earlier. Talk to a genetic counselor to find out what types of genetic testing are available for you and to detect asymptomatic carriers in your family.
Carrier screening can be done before or during pregnancy to find out if either parent carries the gene for SMA.
If your child is known to be at risk for SMA, you and your family may choose to have SMA prenatal testing. There are two types of prenatal tests — chorionic villus sampling (CVS) and amniocentesis. Although CVS can be performed earlier than amniocentesis (after 10 weeks of pregnancy), it’s associated with an increased risk of miscarriage. During this procedure, a small sample of cells is taken from the placenta. Amniocentesis can be performed after 14 weeks of pregnancy. In this procedure, amniotic fluid is taken out by a fine needle. Talk to your care team to find out the best prenatal testing option for you.
There isn’t a lot of information about how SMA treatments can affect you or your baby during pregnancy. Talk to your SMA specialist and your obstetrician about the best treatment option for you before, during, and after your pregnancy.
There are two medications approved by the U.S. Food and Drug Administration (FDA) to treat SMA in adults:
The journal Women’s Health Issues states that pregnant women are often excluded from participating in clinical trials, so it can be hard to tell how a medication might affect the mother and baby. Instead of using studies in humans, doctors can look at animal studies to predict how a drug may affect a pregnancy. In studies in pregnant mice and rabbits, nusinersen didn’t cause any harm to the unborn baby. There isn’t any information about whether nusinersen is present in breast milk.
There haven’t been any studies in humans or animals on the effect of gene replacement therapy, like onasemnogene abeparovec-xioi, on pregnancy or breastfeeding.
Proper nutrition and physical therapy are also important parts of your treatment during and after pregnancy, whether you had a vaginal delivery or a C-section. Exercise can help you maintain muscle strength and avoid complications caused by weight gain.
People with SMA may worry about the additional burden on their family, friends, and caregivers. But you shouldn’t be afraid to ask for help. Talk to your SMA care team about devices that can make caring for your child easier, such as:
Talk to your health care providers about resources available to you. Connecting with other parents with SMA through mySMAteam or other organizations can also help you.
On mySMAteam, the social network for people with spinal muscular atrophy and their loved ones, more than 2,000 members come together to ask questions, give advice, and share their stories with others who understand life with SMA.
Have you or a loved one had a healthy pregnancy while living with SMA? Did you notice any changes in your symptoms during pregnancy? Share your experience in the comments below, or start a conversation by posting on your Activities page.