Several studies have found a higher rate of pregnancy complications, such as pregnancy loss and preeclampsia, in people with neuromyelitis optica.

Neuromyelitis optica (NMO) spectrum disorder, or Devic’s disease, mainly affects the spinal cord and the nerves to the eyes, although it may also involve the brain. People often confuse it for multiple sclerosis.

According to the National Institute for Neurological Disorders and Stroke, NMO is an uncommon disease of the central nervous system.

Individuals with NMO develop optic neuritis and transverse myelitis. Optic neuritis causes pain in the eye and vision loss. Transverse myelitis causes weakness, numbness, and sometimes paralysis of the arms and legs, along with sensory disturbances and the loss of bladder and bowel control.

In 2015, senior author Dr. Maria Isabel Leite, of the United Kingdom’s University of Oxford, and colleagues studied 60 women with a history of at least one pregnancy and a diagnosis of neuromyelitis optica spectrum disorder (NMOSD). The researchers interviewed the participants and reviewed their medical records.

Of the study participants, 40 underwent analysis for pregnancy loss and 57 for preeclampsia, a life threatening condition for both mother and fetus. The symptoms of preeclampsia include high blood pressure and protein in the urine during pregnancy.

Throughout the retrospective study, of the 40 women with a diagnosis of NMO, there were 85 pregnancies. Of these, 13% ended in pregnancy loss, constituting 11 pregnancies in six women. This percentage is similar to the rate in the general population. Pregnancy loss occurred in 43%, or six out of 14 pregnancies occurring after the onset of the disease.

Pregnancies conceived up to 3 years before disease onset were nearly 12 times as likely to end in pregnancy loss, regardless of the mother’s age or history of pregnancy loss.

Women who experienced pregnancy loss within the year before disease onset also had more disease activity in the period starting 9 months before conception and lasting to the end of pregnancy, compared with viable pregnancies.

The rate of preeclampsia was 11.5% in women with NMO, significantly higher than the 3.1% reported in the general population. Preeclampsia was more prevalent in women who also had multiple other autoimmune disorders or pregnancy loss in the most recent previous pregnancy, but disease onset was not a risk factor.

According to Dr. Leite:

“Women with neuromyelitis optica have a high risk of miscarriage, particularly in pregnancies occurring within the 3 years prior to, or after, when the disease starts. So, unfortunately, some of these women may not even know they are going to have the disease at the time of miscarriage.”

Other studies have since corroborated and furthered these findings. A 2018 study found that, in addition to being at higher risk for pregnancy complications, pregnancy may lead to further disability and relapse during pregnancy and postpartum in people with NMO.

A 2017 study on the effects of NMO on pregnancy notes that NMO typically affects women of childbearing age. The study states women are 2 to 9 times more likely than men to have NMO. Hormonal or genetic factors may explain this increased risk.

Limitations of Dr. Leite’s 2015 study include the small sample size, the fact that the researchers studied the patients retrospectively, and the lack of pathological data from placenta samples.

The study suggests a need to prevent disease activity before and during pregnancy to improve pregnancy outcomes in women with the condition.

Some experts suggest people with NMO seek care from a neuroimmunological specialist center for personalized treatment and help with family planning. A specialist can advise someone with NMO on the best course of action for navigating their pregnancy, depending on the individual’s disease history.