Pregnancy Registry, Infants, Serum/Milk Analysis (PRISMA)

Maternal Disease Activity During Pregnancy and Postpartum Assessed by Expanded Disability Status Scale (EDSS)

Changes in maternal disease activity will be assessed using the Expanded Disability Status Scale (EDSS) for individuals with multiple sclerosis (scored from 0 to 10, with higher scores indicating greater disability). Data will be collected via medical record review and participant self-report questionnaires.

Maternal Disease Activity During Pregnancy and Postpartum Assessed by MRI Findings

Changes in maternal disease activity will be assessed using magnetic resonance imaging (MRI) findings, including gadolinium-enhancing lesions, new or enlarging T2 lesions, and brain atrophy. Data will be collected via medical record review.

Maternal Disease Treatment Course During Pregnancy and Postpartum Assessed by Disease Modifying Therapy (DMT) Use

The maternal disease treatment course will be evaluated through an assessment of Disease Modifying Therapy (DMT) used pre-pregnancy to postpartum. This includes the specific type of DMT used in the pre-pregnancy period, any modifications or discontinuation of therapy during pregnancy, and the resumption or initiation of DMTs in the postpartum period. Data will be obtained through medical record review.

Maternal Disease Activity During Pregnancy and Postpartum Assessed by Clinical Relapse Rates

Changes in maternal disease activity will be assessed using the clinical relapse rate. Relapses will be identified based on medical record review and participant self-report questionnaires administered at regular intervals. Additional information, such as the timing, severity, and treatment of relapses, will be collected when available.

Infant Growth and Development Outcomes Assessed by Chart Review and ASQ-3

Infant growth data (weight, length, head circumference) will be extracted from routine clinical records from Well-Child Care Visits up to 12 months. Developmental milestones will be assessed using the Ages and Stages Questionnaire, Version 3 (ASQ-3), administered at 2, 4, 6, 8, 10, and 12 months postpartum. ASQ-3 scores are age-specific and help assess infant communication, motor, problem-solving, and social-emotional development. Higher scores generally indicate better developmental progress.

Detection and Concentration of Monoclonal Antibodies in Breastmilk

Breastmilk samples will be collected following postpartum infusions of anti-B cell therapies (e.g., ocrelizumab, rituximab), natalizumab, or monoclonal antibodies targeting calcitonin gene-related peptide (CGRP) or its receptor. Samples will be collected across 6 timepoints around the first postpartum infusion (pre-infusion; 7 days, 20 days, 30 days, 60 days, and 90 days post-infusion). Samples will be analyzed to detect the presence and concentration of these therapies in breastmilk and predict the relative transfer of medication to infants through breastmilk. Information about breastfeeding behavior including whether participants are exclusively breastfeeding, mixed feeding, or using formula, will be self-reported through accompanying survey or collected through chart review.

Concentration of Monoclonal Antibodies and Disease-Related Biomarkers in Maternal Blood

Maternal blood samples will be collected at various time points: during the planning stage, at 8 months of pregnancy, and during the postpartum period (1, 2, 4, and 6 months postpartum), depending on the participant's ability and willingness to provide a sample. During the postpartum period, a set of blood samples will also be collected pre-infusion, and at 30 and 60 days post-infusion, either separately or in conjunction with other postpartum time points. These samples will be analyzed to determine serum drug levels for pharmacokinetic evaluation, as well as to assess other biomarkers of interest.

Maternal Fatigue During Pregnancy and Postpartum Assessed by Modified Fatigue Impact Scale (MFIS)

Fatigue will be assessed using the Modified Fatigue Impact Scale (MFIS), which evaluates the perceived impact of fatigue on cognitive, physical, and psychosocial functioning. Scores range from 0 to 84. Higher scores indicate greater fatigue impact. This will be administered at baseline, 8 months of pregnancy, and during the postpartum period at 1, 4, 8, and 12 months.

Exploratory: Changes in Maternal Gut Microbiome Composition Following Maternal Monoclonal Antibody Treatment

Stool samples from mothers will be collected at key time points before and after the first maternal monoclonal antibody treatment resumption (pre-infusion; 30 days and 60 days post-infusion) to evaluate changes in gastrointestinal microbial populations.

Exploratory: Changes in Infant Gut Microbiome Composition Following Maternal Monoclonal Antibody Treatment

Stool samples from infant will be collected at key time points before and after the first maternal monoclonal antibody treatment resumption (pre-infusion; 30 days and 60 days post-infusion) to evaluate changes in gastrointestinal microbial populations.

Exploratory: Infant Medical Problems Inflicting Immune Functions

Immune function of infants whose mothers received anti-B cell therapies, natalizumab, or monoclonal antibodies to calcitonin gene-related peptide (CGRP) or its receptor will be monitored using clinical data (e.g., lymphocyte counts from cord blood and infant bloodwork) when available through standard medical care.

Exploratory: Changes in Maternal Vaginal Microbiome Composition During Pregnancy

Vaginal swab samples from mothers will be collected at a key time point to determine the effect of mAb treatment on vaginal microbial populations in mothers.