Disease activity during pregnancy
For some women with MS, pregnancy brings about fewer MS symptoms. This may be due to the body’s immune system being more tolerant of the growing human being inside. Clinical and MRI disease activity related to MS are suppressed, particularly during the third trimester. This connection has led to research using hormones such as estriol to treat MS. So far the studies have been small, showing modest benefit.
Disease-modifying therapy during pregnancy
Women with MS are encouraged to stop disease-modifying therapy (DMT) once they become pregnant, if they had not already stopped DMT use when trying to get pregnant. Women with MS who become pregnant while on a DMT should consider participating in a formal pregnancy registry such as the one sponsored by MothertoBaby.org or those hosted by pharmaceutical companies. Several small studies have reported outcomes related to the use of DMTs during pregnancy, particularly during the first trimester, but information is still limited. Data suggest that glatiramer acetate or interferon beta are safe to use. However, each person with MS needs to make personal decisions regarding DMT use and pregnancy in collaboration with her doctor.
New FDA drug pregnancy categories
Based on a 2014 decision, the Food and Drug Administration (FDA) is replacing the previous system used to classify risk of using prescription drugs during pregnancy – A, B, C, D and X – with three detailed subsections that describe risks in real-world context: pregnancy (including labor and delivery), lactation, and a new section related to females and males of reproductive potential.
Relapse management during pregnancy
Women with MS have fewer relapses during pregnancy, but when they do occur, it is usually during the first and second trimesters. Relapses that do occur during pregnancy are often treated safely with short-term high-dose IV corticosteroids (methylprednisolone). Dexamethasone can cross the placenta and should be avoided. While there is not enough evidence to suggest that MRI scans up to 3 Tesla strength are harmful to a fetus, women who are pregnant should avoid gadolinium contrast because it can cross the placenta and enter the fetus’ bloodstream.
Symptom management during pregnancy
As data is limited, medications used to treat symptoms of MS should be evaluated carefully and used at their minimum effective dose for as short a time as possible during pregnancy. When there are options, drugs with the more favorable pregnancy rating should be used.
Childbirth: delivery and anesthesia
Pregnancy in women with MS is not considered high-risk and decisions related to anesthesia and delivery method should be made in collaboration with the patient’s obstetrician. Pastò et al. (2012) indicate that epidural analgesia and caesarean delivery have no impact on risk of postpartum relapse or disability progression. The only consideration that may need to be made would be in the case of more disabled pregnant MS women for whom assisted vaginal delivery or cesarean section may be necessary.
Postpartum disease activity
During the first three months after childbirth, women with MS are more likely to experience relapses or MRI disease activity, but the risk returns to normal in less than a year. Factors associated with postpartum relapse include higher relapse rate and disability prior to pregnancy, lack of prior DMT use, and relapse during pregnancy. Rates of postpartum relapse range from 14 percent to 30 percent in MS studies. Small-scale studies have evaluated postpartum prophylactic intravenous immune globulin (IVIG), as well as pulse corticosteroids, to minimize relapses with reported success. Hormonal therapy has not shown benefit in suppressing postpartum relapse or MRI disease activity.
The choice of breastfeeding for women with MS is closely tied to the decision to use disease-modifying therapy. Glatiramer acetate (Copaxone, Glatopa) and interferon beta (Avonex, Plegridy, Betaseron, Extavia, Rebif) are considered safe to use while breastfeeding. The other MS DMTs are not considered safe for breastfeeding. While corticosteroids can be detected in breast milk, the amount is greatly reduced 2- to 4-hours after infusion which can be taken into account when using steroids to treat postpartum relapse in breastfeeding patients. While some studies have suggested that breastfeeding is associated with suppression of disease activity, data is limited. Finally, a couple of studies have suggested that breastfeeding exclusively for more than four months reduces the risk of developing MS for the child.
Disease-modifying therapy after delivery
For women at higher risk of postpartum relapse -- those with very active disease, poor prognostic profile, relapse during pregnancy, or no prior DMT use -- it may be advisable to plan on starting a DMT shortly after delivery. In a recent study, Tysabri (natalizumab) started within eight days of delivery was able to prevent postpartum relapses in five of six highly active patients.
See more helpful articles:
Family Planning in the Modern Day of MS
Pregnant With MS: Drug Exposure
Drugs to Take (And Not to Take) When Pregnant With MS
Pregnancy, Infertility and Hormones: MS and Motherhood
Breastfeeding and MS Drugs: What Is Safe to Take?
Coyle PK. Management of women with multiple sclerosis through pregnancy and after childbirth. Ther Adv Neurol Disord. 2016;9(3):198–210. DOI:10.1177/1756285616631897