Fertility Rates Among Women With MS Are Far Below General Population

The fertility rate is lower among women with MS compared with the general population.

Women with multiple sclerosis (MS) have a lower fertility rate than the general population. These are the findings of a study published in Journal of Neurology, Neurosurgery & Psychiatry.

MS typically affects women of childbearing age and common therapeutic interventions can affect fertility. However, most women with MS can have a potentially normal pregnancy and delivery with proper counseling and treatment planning.

This study was designed to evaluate recent trends in fertility and childbearing among women with MS. Researchers identified women (n=2,748) living with MS in Campania in Italy between 2018 and 2020 in health record databases and evaluated them for MS treatments, fertility, and childbirth outcomes. Women with MS who had a pregnancy (n=151) were compared with 3 reference populations: women in the general population of Italy (n=1,248,055) or Campania (n=139,858) and women with MS who did not have a pregnancy (n=2,597).

The incidence rate of pregnancy in MS was 1.17 per 100 person-years (py) and the total fertility rate was 0.58 per woman with MS. In Campania, the total fertility rate during the same period was 1.29 per woman of childbearing age and in Italy, was 1.25 per woman of childbearing age.

Family planning and subsequent DMT decisions should aim to achieve successful pregnancy, delivery and breastfeeding outcomes, while controlling disease activity.

Women with MS who had a pregnancy were mean age, 32.0 (SD, 4.4) years at delivery; 64.2% had not had a previous pregnancy; 16.5% had 1 or more spontaneous abortions; 96.7% did not use reproductive technology for their pregnancy; 67.1% delivered at 37-41 weeks; and 39.5% had a spontaneous delivery. The offspring (n=154) were born at 2,500-3,299 g (47.4%), 3,300 g or more (42.9%), 1500-2499 g (7.1%), or 1,500 g or less (2.6%) and 99.3% had an Apgar score of 7-10.

Compared with the women with MS who did not have a pregnancy, those with pregnancy were younger (mean, 35.10 vs 38.15 years; P <.01) and had been exposed to disease-modifying treatments (DMTs) for a shorter period of time (mean, 21.0 vs 29.3 months; P <.01), respectively.

All deliveries were livebirths, however, 1 infant died in the first 7 days. A total of 5 birth defect cases were observed: Klinefelter syndrome, cleft palate with cleft lip, Ostium secundum, short frenulum of lip, and low birth weight.

Birth defects occurred in dimethyl fumarate- (9.5%), fingolimod- (9.1%), and natalizumab- (6.6%) exposed pregnancies.

At the time of conception, 26.6% of women were untreated or had discontinued DMT use, 50.0% discontinued DMTs at pregnancy, and 23.4% continued on treatment during pregnancy.

Use of DMTs during pregnancy associated with lower birthweight compared with discontinuation after conception (adjusted coefficient, -107.09; P = .03); and, use of DMTs of unknown or with negative effects on pregnancy associated with birth defects compared with safe DMTs (adjusted odds ratio [aOR], 8.88; P = .02).

“Fertility in MS has remained far below the general population, with twofold smaller rate of women with MS becoming pregnant during the study period …,” the researchers noted. They concluded, “Family planning and subsequent DMT decisions should aim to achieve successful pregnancy, delivery and breastfeeding outcomes, while controlling disease activity.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Moccia M, Affinito G, Fumo MG, et al. Fertility, pregnancy and childbirth in women with multiple sclerosis: a population-based study from 2018 to 2020. J Neurol Neurosurg Psychiatry. Published online April 17, 2023. doi:10.1136/jnnp-2022-330883