“A pregnancy test should be administered prior to every treatment with a chemotherapeutic or cytotoxic agent in a woman of child-bearing age, even if she thinks her periods have ceased as a result of chemotherapy treatment,” she said. “They may have ceased due to pregnancy, and we don’t want to treat our pregnant patients with chemotherapy.”
The approximate risk of MS is 1 in 500 in the general population, 1 in 100 in people with an affected second-degree relative, 1 in 50 with an affected first-degree relative, and 1 in 4 in monozygotic twins born to an affected mother, according to Dr. Houtchens.
Babies born to MS moms face a risk of being slightly smaller for gestational age by weight (odds ratio, 1.45) but their Apgar scores are the same as their healthy mom counterpart babies. MS moms face a slight risk for operative deliveries but no increased risk for birth defects or other adverse fetal outcomes specifically related to MS. The method of labor and delivery does not impact the postpartum course of the disease, she said.
“Epidural anesthesia is perfectly safe and does not impact the postpartum course of MS,” Dr. Houtchens said. “There’s still an ongoing misconception [about this], especially among obstetric providers and anesthesiologists. Multiple studies have been published stating that there is no increased risk of relapse in these patients after they get an epidural. If they don’t want an epidural, that’s okay, but they shouldn’t be denied it because they have MS.”
Secondary MS symptoms may be affected by pregnancy, including fatigue, bladder symptoms, and mobility difficulty due to increased weight. IV corticosteroids are used widely to treat MS relapses during pregnancy, as well as in obstetrics to speed fetal lung maturity.
Steroids “cross the placental barrier and may increase the risk of cleft palate when used in the first trimester or may cause lower birth weight in the baby and earlier than expected delivery. They could also in theory delay healing for the mother after giving birth,” she said.
However, prednisone, prednisolone, and methylprednisolone can be administered with low levels of fetal exposure. “These agents are metabolized to inactive forms by 11 beta-hydroxysteroid dehydrogenase in the placenta, allowing less than 10% of the maternal dose to reach the fetus,” she said. Betamethasone and dexamethasone cross the placenta with minimal metabolism, leading to direct full-dose effects on the fetus.
Dr. Houtchens cautioned that none of the available MS drugs should be used in pregnant patients.
“It appears that pregnancy itself is protective enough that we don’t need to use a drug to keep them healthier,” she said.
For a nonlactating patient, it’s safe to resume MS therapy within 1 week after birth. For a lactating patient with previously active disease, it may be safe to administer monthly steroids or monthly IVIG, instructing them to discontinue breastfeeding for 24 hours after treatment. In breast milk, beta-interferon agents are found at 0.006% of the maternal dose. Oral small molecules such as fingolimod and dimethyl fumarate “are freely passed in breast milk at a lower level than in sera but are more likely to directly affect the infant’s immune/neurological systems,” Dr. Houtchens said. “Hepatic clearance is slower in infants. We don’t have anyone at our MS center taking any MS medications and breastfeeding. Is this the right thing to do? I don’t know. But if you have someone who really wants to breastfeed, you could theoretically put them on an injectable medication.”
MRI should be repeated within 6 months postpartum to assess radiographic disease activity, she recommended.
Dr. Houtchers pointed out that postpartum depression is common in mothers with MS, “and it’s probably under-studied in general.” In fact, the lifetime prevalence of major depressive disorder in people with MS is estimated to be approximately 50%, while the rate of suicides among people with MS is 7.5 times greater than that of the general population.
Helping MS patients navigate conception, pregnancy, and the postpartum period is just the beginning.
“You’re still going to be her doctor,” Dr. Houtchens said. “She’s still going to have that child for the rest of her life. How is she going to deal with raising the child with all of the symptoms of her disease over time? How is she going to relate to her child? You’re going to walk this road with your patients, as one of their most important health care providers.”
Dr. Houtchens disclosed that she has received research grants from Genzyme Sanofi, Biogen Idec, and Novartis. She has also served as a consultant for Teva Pharmaceuticals, Genzyme Sanofi, Questcor, Biogen Idec, and Novartis.