Individuals with multiple sclerosis (MS) can get pregnant, as the condition does not typically affect the ability to conceive or carry a pregnancy to term. MS does not increase the risk of miscarriage, stillbirth, or major birth defects compared to the general population. Modern medical management allows for successful, planned pregnancies, but requires careful coordination between the patient, their neurologist, and their obstetrician. Proactive planning is necessary to ensure both the mother’s disease stability and fetal safety.
Conception and Pregnancy’s Effect on MS Activity
Pregnancy profoundly alters the immune system, leading to a reduction in MS disease activity for most individuals. This phenomenon is often referred to as the “protective effect” of pregnancy and is related to hormonal shifts. The body shifts its immune response toward a T-helper 2 (Th2) dominance, which is less inflammatory compared to the Th1 dominance typically associated with MS relapses.
This beneficial effect becomes most pronounced during the later stages of pregnancy. Studies show that the annualized relapse rate can decrease significantly, particularly in the third trimester, sometimes by as much as 70% compared to the year before conception. The concentration of hormones like estrogen increases continuously, maximizing this protective effect. While this immune shift reduces inflammatory relapses, some MS symptoms like fatigue, mobility issues, or bladder dysfunction might still be temporarily exacerbated due to the physical demands of a growing pregnancy.
Managing MS Treatments During Pregnancy Planning
Pre-conception planning is important because many Disease-Modifying Therapies (DMTs) carry risks to the fetus and must be discontinued before attempting conception. The ideal time to begin discussions with a healthcare team is approximately six months before trying to conceive. This timeline allows for a smooth transition, ensuring the MS is stable and any necessary drug washout period is completed.
Some DMTs, such as teriflunomide and fingolimod, are strictly contraindicated and require a mandatory washout period due to fetal risks. For teriflunomide, this involves an accelerated elimination procedure using medications like cholestyramine to clear the drug from the body. Certain high-efficacy therapies, like anti-CD20 monoclonal antibodies (e.g., ocrelizumab), can be strategically administered before conception, offering prolonged disease control that lasts throughout much of the pregnancy without further dosing.
Individuals using DMTs associated with severe rebound disease activity upon cessation, such as natalizumab or S1P modulators, require careful planning. The neurologist may recommend switching to a different therapy with a safer pregnancy profile or utilizing a “treatment holiday” with close monitoring. If an acute relapse occurs during pregnancy, it can be treated with temporary, high-dose corticosteroids, which are considered safe after the first trimester.
Labor, Delivery, and Postpartum Relapse Risk
MS usually does not dictate the method of childbirth; the type of delivery is based on standard obstetrical considerations. Having MS does not automatically necessitate a Cesarean section. Modern evidence supports the safety of neuraxial anesthesia, including epidurals and spinal blocks, for individuals with MS. Concerns that these anesthetics might trigger a relapse have largely been disproven, and they can be used safely for pain management during labor.
The greatest concern for MS activity occurs in the immediate postpartum period due to the swift reversal of the protective immune state. Following delivery, the annualized relapse rate significantly increases, peaking in the first three to six months. This surge is attributed to the rapid drop in pregnancy hormones like estrogen and the return of a pro-inflammatory immune environment. The risk of a relapse is almost doubled in the first three months postpartum.
Breastfeeding and Medication Decisions
The decision regarding breastfeeding often involves a complex balance between the known benefits for the infant and the mother’s need to resume highly effective DMTs quickly. Exclusive breastfeeding itself has been associated with a lower risk of postpartum relapse, suggesting a mild protective effect. However, this benefit must be weighed against the mother’s personal disease activity and the safety of her specific medication.
Some injectable DMTs, such as glatiramer acetate and interferon beta, are compatible with breastfeeding because they are large molecules that minimally transfer into breast milk. For individuals with more aggressive MS, the need to quickly resume highly effective therapy to mitigate the high postpartum relapse risk often takes precedence. The safest and most effective strategy must be determined through an individualized consultation with the neurologist and pediatrician, considering the severity of the mother’s MS and the specific properties of the planned DMT.