Vitamin D and Postpartum Multiple Sclerosis Relapses (P4.364)

Objective: To determine if lower vitamin D levels are associated with an increased risk of postpartum relapses. Background: Multiple sclerosis (MS) affects more than 280,000 American women, most of whom develop the disease during their reproductive years. The fear of postpartum relapses influences family planning, treatment and breastfeeding choices, yet little is known about how to minimize relapse risk. An attractive hypothesis is the vitamin D-MS relapse relationship because vitamin D deficiency is endemic worldwide, particularly in pregnant and lactating women, offering a potentially high-impact strategy to reduce postpartum relapses. Design/Methods: We prospectively followed 89 pregnant women with MS from Kaiser Permanente Southern and Northern California for one year postpartum. Serum 25-hydroxyvitamin D (25OHD) was measured using liquid chromatography, tandem mass spectrometry during third trimester, one and three months postpartum. Other exposures and outcomes were collected from structured interviews and electronic health records. Data were analyzed using longitudinal multivariable methods. Results: During pregnancy, most women (88%) were vitamin D sufficient (>30 ng/mL) and took prenatal vitamins (93%) but no additional vitamin D supplements (78%). The median 25OHD level was 38 ng/mL (interquartile range, 32–42). Lower pregnancy levels were not associated with an increased risk of postpartum relapses ( Conclusions: Lower vitamin D levels during pregnancy or early postpartum were not associated with an increased risk of postpartum relapses. Taken together with previous studies, our findings imply that extra vitamin D supplementation beyond prenatal vitamins is unlikely to decrease the risk of postpartum MS relapses. Study Supported by: National Multiple Sclerosis Society (RG4809-A PI: Langer-Gould) Disclosure: Dr. Smith has nothing to disclose. Dr. Leimpeter has nothing to disclose. Dr. Albers has nothing to disclose. Dr. Kerezsi has nothing to disclose. Dr. McClearnen has nothing to disclose. Dr. Van Den Eeden has nothing to disclose. Dr. Langer-Gould has nothing to disclose.