Is It Safe to Get Pregnant with Multiple Sclerosis?

Multiple Sclerosis (MS) is the most common disabling disease of the central nervous system in young adults and is particularly common in young to middle aged female adults, when they’re at the right ages to think about starting their family.

Pregnancy and Multiple Sclerosis

Pregnancy initiates physiologic changes in all organ systems, including the immune and nervous systems, i.e., those implicated in the pathophysiology of MS. Furthermore, the management of MS requires lifelong treatment in most cases, and some of the disease modifying treatments (DMTs) used in this context can also be harmful to fetal development.

The approach to pregnancy and MS can be summed up under several key points:

• Preconception planning.
• Effects of MS on pregnancy and effects of pregnancy on MS.
• Use of DMTs during pregnancy.
• Treatment of MS attacks.
• Chronic MS symptom management.

Preconception Planning

Ideally, pregnancy in a woman with MS should be preplanned and when MS symptoms are stable, ideally at least a year after the initial diagnosis. Typical preconception advice of avoiding smoking, alcohol as well as prioritizing sleep and an adequate diet are important. Furthermore, studies have shown that Vitamin D levels of less than 30 nmol/L are associated with increased MS risk in children thus Vitamin D supplementation is even more so important for patients with MS planning to get pregnant.

Live vaccines are generally contraindicated with pregnant women with MS, but other vaccines such as those against influenza and SARS-CoV-2 are safe and recommended.

Most expert guidance is for women with MS planning pregnancies to stop treatment with DMTs. The best approach is to minimize the time off of DMTs by way of ovulation prediction to improve odds of conception as well as early referral to a contraception specialist if conception is not achieved. Furthermore, as some of the DMTs can be teratogenic with longer half-lives, an appropriate washout period is recommended based on the biological half-life of the medication. This can be up to six months in the context of some antibodies such as rituximab or ocrelizumab.

However, for patients on older injectable DMTs such as beta interferons or glatiramer, registry data as well as expert opinion show that they are safe to continue while trying to conceive.

MS does not increase risk of complications of pregnancy and fetal anomalies have not been shown to be associated with maternal MS in large cross-sectional registries. Interestingly, one study demonstrated that patients with MS were about 10% more likely to deliver via cesarean sections; and another study demonstrated that mothers with MS had a 2.2 % more chance of having a baby that was small for gestational age.

Effects of Pregnancy on MS

Pregnancy is not detrimental for MS au contraire has a beneficial effect on attacks. Particularly the third trimester of MS has been shown to be as potent as some DMTs against MS attacks. A meta-analysis of 13 studies with over 1200 pregnancies in women with MS has demonstrated that while pregnancy is associated with a decrease in MS attacks, postpartum period is associated with an increase that needs to be counseled to the patient. However, studies have also shown that cumulative lifetime disability of MS is not necessarily affected by pregnancy.

Use of DMTs during Pregnancy

MS attack rates are decreased during pregnancy, and most experts agree that DMTs can be paused with careful planning especially in women with mild to moderate disease. Furthermore, some DMTs are teratogenic and are contraindicated during pregnancy. However, if dictated by the patient’s MS some DMTs such as glatiramer and natalizumab can be considered during pregnancy. A systematic review of 15 studies covering almost 1000 pregnancies did not find any association between natalizumab and glatiramer acetate and lower birth weight, lower birth length or shorter gestational age as well as congenital anomalies and spontaneous abortion.

Treatment of Acute MS Attacks

Treatment of acute MS attacks are relatively challenging in the context of pregnancy as the mainstay of management, IV methylprednisolone is controversial particularly in the first trimester. Historical studies have demonstrated increased risk of craniofacial anomalies such as cleft lip with glucocorticoid use in the first trimester, which have been challenged by newer and larger studies that have shown no association.

Short term, high-dose IV glucocorticoids however, are considered relatively safe during the second and third trimester and can be utilized for management of acute MS attacks. Of note, oral methylprednisolone has high bioavailability to fetus and thus management should ideally be one on an intravenous basis.

Ongoing MS Symptoms and Pregnancy

Pregnancy can complicate the management of common long-term MS symptoms such as bladder issues and fatigue. Furthermore, some medications used in long-term management may be contraindicated during pregnancy, particularly those used to manage depression, pain, and spasticity. As such careful planning of a patient's symptoms as well as appropriate management with alternatives during different trimesters is warranted.