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Pregnancy and MS

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Pregnancy Has Little Impact on MS


Until the 1950s, it was widely assumed that pregnancy had an adverse effect on the course of MS. In more recent research, however, a very different view has emerged. It is now believed that pregnancy has relatively little impact on the disease course, and may even provide temporary protection against relapses. Equally important, MS does not seem to alter the course or outcome of pregnancy. "Pregnancy is an immunosuppressed state, and MS is an autoimmune disease, so it is not completely surprising that some aspects of MS would improve during pregnancy", said Kathy Birk, MD, in an interview.

Nevertheless, several important issues should be considered in MS patients who are pregnant or contemplating pregnancy, noted Dr. Birk, an obstetrician/gynecologist affiliated with Genesee Hospital in Rochester, NY. Of particular concern is the increased risk of relapse during the postpartum period, as well as the risk of significant fatigue - a common postpartum feature in women with and without MS. Also of concern are the risk/benefit dilemmas that inevitably arise whenever pharmacologic treatments are considered during the course of pregnancy.

A Protective Effect?

"No study has clearly demonstrated a negative consequence of pregnancy on the long-term course of MS," noted Denise Damek, MD, and Elizabeth A. Schuster, MD, in a recent article in the Mayo Clinic Proceedings.  "To the contrary, current knowledge suggests that pregnancy might have a mitigating influence on the disease. "Of 14 published studies that have examined pregnancy's immediate effects on MS, 10 found a decrease in relapse rates. In a 1995 study, for example, researchers at Sahlgrenska Hospital, in Goteborg, Sweden, found that pregnant women with MS were significantly less likely to reach level 6 of the Disability Status Scale that were non-pregnant control patients matched for MS duration and neurologic deficits.

The risk of MS relapse in the six months after giving birth is two to three times greater than the risk in non-pregnant counterparts; an estimated 20% to 40% of MS patients will have a clinical relapse or worsening of disability during this period. This temporarily increased risk, however, does not affect the likelihood of sustained disability. "In fact, a full-term pregnancy may increase the time interval to reaching a common disability end point - walking with the aid of a cane or crutch - or to having a secondarily progressive course," according to Drs. Damek and Shuster.

"The factors that cause the apparent disease suppression in MS [during pregnancy] are yet to be isolated, but they may have some therapeutic potential," Dr. Birk noted. "There are, for example, changes in T-cell-mediated responses, which seem to be important in MS activity. "A potential contributor to immunosuppression is a-fetoprotein, which is elevated in the serum of pregnant women and can prevent the development of experimental allergic encephalomyelitis.

In The Planning Stage

Patients' questions about MS and pregnancy are often raised first with the neurologist, Dr. Birk pointed out. "Women with chronic diseases have a tendency not to go to doctors other than the ones involved in managing their primary health problem," she said. "This means that women with MS may not receive routine preventive care. "It is important to ask these patients whether they plan to become pregnant, Dr. Birk advised.  "If they do, send them for preconception counseling."

Adequate folic acid intake (0.4 mg/d) is important even for women who are merely considering conception, Dr. Birk stressed. "If the patient is two months' pregnant by the time she starts to take folic acid, it is too late for maximum benefit in preventing neural tube defects."

Dilemmas of Treatment

Whenever any chronic illness coincides with pregnancy, questions arise about the safety of continuing treatment. Medications that may be harmful to the developing fetus should - whenever possible - be discontinued before conception or immediately after an unplanned pregnancy is detected. The interferon drugs, for example, are considered pregnancy category C agents; dose-related abortifacient activity has been reported in animal studies. Category B drugs, such as glatiramer acetate, have shown no harmful fetal effects in animal studies; definitive human pregnancy data have not been reported. In general, medications should be continued during pregnancy only if clearly needed.  Moreover, magnetic resonance imaging is generally contraindicated in pregnancy.

  Pregnancy Classifications

for Drugs Used in MS Care

Category X:

Contraindicated During Pregnancy

  • Methotrexate


Category D:

Cause Fetal Harm

  • Azathioprine
  • Cladribine

Category C:

Cause Fetal Harm in Animals
(no human studies)

  • Amantadine
  • Baclofen
  • Carbamazepine
  • Tizanidine
  • Interferon B-1a
  • Interferon B-1b
  • Corticosteroids

Category B:

Cause no Fetal Harm in Animals
(no human studies)

  • Glatiramer
  • Oxybutynin
  • Pemoline

"Once a pregnancy is under way," Dr. Birk commented, patients may benefit from the associated disease-modulating effects. However, conception "sometimes takes many months, and deciding to forego treatment during that time is a major decision," she pointed out.

Corticosteroids have been used during pregnancy, but are classified in pregnancy category C; neonatal adrenal suppression and other adverse effects have been reported. Relaxation exercises and massage may be preferable to medication for treating spasticity during pregnancy, said Dr. Birk. Patients should also understand "that some muscle cramps are a normal part of pregnancy and are not necessarily related to MS."

The Routine Problems

Pregnancy may exacerbate some problems routinely encountered by women with MS, including urinary tract infections (UTIs), constipation, fatigue and falling. "Some women who have chronic problems with UTI may benefit from taking a maintenance antibiotic during pregnancy," Dr. Birk said. She recommends regular urine culture/sensitivity testing in women with MS due to the risk of pyelonephritis.

Constipation is common in both MS and pregnancy. "Prenatal vitamins with high amounts of iron may make that a bigger issue," Dr. Birk said. However, she urges patients with MS not to avoid such supplements, since anemia can worsen any existing fatigue. Instead, she said, patients "Need to include a lot of water and a lot of fiber in the diet if they are taking vitamins with iron."

In the later stages of pregnancy, gait imbalance is not uncommon, even among women with no preexisting neurologic illness. The phenomenon may be particularly pronounced among primigravidas, Dr. Birk noted. "For women with MS, this is an important issue. It is important to teach patients how to avoid falls and what can be done to make falls less likely in the home."

Finally, Dr. Birk recommended that women with MS carefully plan the postpartum period to ensure adequate rest. If possible, she suggested, women who work outside the home might arrange for more than the typical six to eight weeks of postpartum leave in order to cover the period of increased relapse risk. Women who choose not to breast-feed might consider early initiation or resumption of disease-modifying treatment.
"The immunosuppressive factors are not there after pregnancy," Dr. Birk observed. "On top of that is the built-in fatigue and exhaustion that all new mothers have. "Patients with MS should plan ahead for conception, Dr. Birk said in conclusion. Major considerations, she added, include the availability of a support network to help care for the newborn. 

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