studies published in the Neurology
evaluated the maternal and fetal consequences of stopping the monoclonal
antibody natalizumab in women with multiple sclerosis either well before
pregnancy or within the first few days of the pregnancy
- Natalizumab is
usually discontinued in women with multiple sclerosis well before
pregnancy due to the risk of miscarriages and possible congenital
- Early discontinuation
and a delay in re-institution of the treatment appears to be associated
with a higher risk of relapses.
- The risk of
congenital abnormalities due to the exposure of natalizumab during early
pregnancy is not very clear.
. The studies
evaluated 92 pregnancies.
In the study that
evaluated the maternal risks:
- The relapse rate
of multiple sclerosis during and
after the pregnancy was three times higher (37%) in the women that
discontinued natalizumab than those who never received it (10%).
- The relapses were
particularly more common during the first three months of pregnancy and following delivery.
- The relapses were
more common if natalizumab was stopped earlier during pregnancy.
- The number of
relapses following the delivery appeared to be lesser with the early
re-introduction of disease modifying drugs following the delivery.
In the study that evaluated fetal risks,
women with multiple sclerosis who continued to use natalizumab up to the first
trimester were included. Most of these women stopped the drug within a week of
the pregnancy. The scientists found that:
two studies indicate that by delaying the discontinuation of natalizumab to
just before pregnancy and the early resumption of treatment following the
delivery could be associated with lower risk of relapse in women
- The rate of
spontaneous abortions (miscarriage) was four times higher than what
occurred in women with multiple sclerosis who received interferon or no
treatment during pregnancy. The risk of 17.4% that occurred in these women
was, however, similar to that in the general population (14%).
- The risk of
congenital abnormalities in the babies of 3.7%, was again similar to that
of the general population.
- Exposure to
natalizumab and interferon-β was associated with lower length and weight
of the babies.
evidence is required on the development of congenital abnormalities on the baby
if the drug is stopped late. The study did not report the severity of the
relapses, which could throw more light on the issue.
Natalizumab is used for the treatment of
multiple sclerosis in those patients who do not respond to or are unable to
tolerate other medications
. Multiple sclerosis is a condition where
antibodies attack the covering of nerves, eventually resulting in nerve damage.
‘Two published studies discuss the maternal and fetal risks of stopping natalizumab in multiple sclerosis patients well before or within the first few days of pregnancy.’
acts on the immune system and prevents the damage to the nervous system
. A single
dose is administered intravenously every 4 weeks. It is also used for the
treatment of Crohn's disease. Adverse effects include headache
fatigue, depression, skin rash,
digestive tract problems, infection, and bone and joint pain. Possible serious
adverse effects include a brain infection called progressive multifocal
leukoencephalopathy, liver damage, allergic reaction, and herpes infection.
Interferon beta is currently used for the treatment of multiple sclerosis
- Portaccio E et al. Pregnancy decision-making in women with multiple sclerosis treated with natalizumab I: Fetal risks. Neurology Feb 2018. DOI: 10.1212/WNL.0000000000005067
- Portaccio E et al. Pregnancy decision-making in women with multiple sclerosis treated with natalizumab II: Maternal risks. Neurology Feb 2018. DOI: 10.1212/WNL.0000000000005068