Effect of pregnancy on the prognosis for multiple sclerosis. A 5-year follow up investigation

Conceiving complexity: Biological mechanisms underpinning the lasting effect of pregnancy on multiple sclerosis outcomes

Multiple sclerosis (MS) is an autoimmune, demyelinating disease with the highest incidence in women of childbearing age. The effect of pregnancy on disease activity and progression is a primary concern for women with MS and their clinical teams. It is well established that inflammatory disease activity is naturally suppressed during pregnancy, followed by an increase postpartum. However, the long-term effect of pregnancy on disease progression is less understood. Having had a pregnancy before MS onset has been associated with an older age at first demyelinating event, an average delay of 3.4 years. After MS onset, there is conflicting evidence about the impact of pregnancy on long-term outcomes. The study with the longest follow-up to date showed that pregnancy was associated with a 0.36-point lower disability score after 10-years of disease in 1830 women. Understanding the biological mechanism by which pregnancy induces long-term beneficial effects on MS outcomes could provide mechanistic insights into the elusive determinants of secondary progression. Here, we review potential biological processes underlying this effect, including evidence that acute sex hormone exposure induces lasting changes to neurobiological and DNA methylation patterns, and how sustained methylation changes in immune cells can alter immune composition and function long-term.

Parity is associated with long-term differences in DNA methylation at genes related to neural plasticity in multiple sclerosis

BACKGROUND

Pregnancy in women with multiple sclerosis (wwMS) is associated with a reduction of long-term disability progression. The mechanism that drives this effect is unknown, but converging evidence suggests a role for epigenetic mechanisms altering immune and/or central nervous system function. In this study, we aimed to identify whole blood and immune cell-specific DNA methylation patterns associated with parity in relapse-onset MS.

RESULTS

We investigated the association between whole blood and immune cell-type-specific genome-wide methylation patterns and parity in 192 women with relapse-onset MS, matched for age and disease severity. The median time from last pregnancy to blood collection was 16.7 years (range = 1.5-44.4 years). We identified 2965 differentially methylated positions in whole blood, 68.5% of which were hypermethylated in parous women; together with two differentially methylated regions on Chromosomes 17 and 19 which mapped to TMC8 and ZNF577, respectively. Our findings validated 22 DMPs and 366 differentially methylated genes from existing literature on epigenetic changes associated with parity in wwMS. Differentially methylated genes in whole blood were enriched in neuronal structure and growth-related pathways. Immune cell-type-specific analysis using cell-type proportion estimates from statistical deconvolution of whole blood revealed further differential methylation in T cells specifically (four in CD4⁺ and eight in CD8⁺ T cells). We further identified reduced methylation age acceleration in parous women, demonstrating slower biological aging compared to nulligravida women.

CONCLUSION

Differential methylation at genes related to neural plasticity offers a potential molecular mechanism driving the long-term effect of pregnancy on MS outcomes. Our results point to a potential 'CNS signature' of methylation in peripheral immune cells, as previously described in relation to MS progression, induced by parity. As the first epigenome-wide association study of parity in wwMS reported, validation studies are needed to confirm our findings.

The role of sex and pregnancy in multiple sclerosis: what do we know and what should we do?

INTRODUCTION

Multiple sclerosis (MS) is more prevalent in women than in men. The sex of the patient, and pregnancy, are reported to be associated with the clinical features of MS. The mechanism of this is unclear.

AREAS COVERED

This review summarizes data about sex differences in MS and the role of pregnancy. Possible mechanisms for the effects of sex and pregnancy are summarized, and practical suggestions for addressing these issues are provided.

EXPERT OPINION

There is considerable interdependence of the variables that are associated with MS. Men have a worse outcome of MS, and this could be due to the same factors that lead to greater incidence of neurodegenerative disease in men. The possible role of parity on the long-term outcome of MS is of interest. Future studies that look at the mechanisms of the effects of the sex of the patient on the outcome of MS are required. However, there are some actions that can be taken without further research. We can concentrate on public health measures that address the modifiable risk factors for MS and ensure that disease is controlled in women who intend to become pregnant and use appropriate disease modifying agents during pregnancy.

The role of sex hormones in women with multiple sclerosis: From puberty to assisted reproductive techniques

BACKGROUND

Multiple Sclerosis is a multifactorial chronic autoimmune disease, affecting predominantly females in the fertile age. Sex hormones changes during a woman's life, from puberty to menopause, including pregnancy and puerperium, may influence the onset and course of Multiple Sclerosis. The effect of estrogen levels on immune, clinical and radiological aspects of Multiple Sclerosis, also stimulated investigation on the effect of sexual hormones therapies, such as oral contraceptives and assisted reproductive technique, on the Multiple Sclerosis course.

SEARCH STRATEGY AND SELECTION CRITERIA

A literature search for original articles and reviews was conducted in the databases, including PubMed, Scopus, and ClinicalTrials.gov of the U.S. National Library of Medicine site from 1988 to 2020.

RESULTS AND CONCLUSION

This review reports the effects of the physiological and iatrogenic hormonal changes either on immune or clinical or paraclinical features in the different life stages of women affected by Multiple Sclerosis.

Sex effects across the lifespan in women with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating central nervous system disorder that is more common in women, with onset often during reproductive years. The female:male sex ratio of MS rose in several regions over the last century, suggesting a possible sex by environmental interaction increasing MS risk in women. Since many with MS are in their childbearing years, family planning, including contraceptive and disease-modifying therapy (DMT) counselling, are important aspects of MS care in women. While some DMTs are likely harmful to the developing fetus, others can be used shortly before or until pregnancy is confirmed. Overall, pregnancy decreases risk of MS relapses, whereas relapse risk may increase postpartum, although pregnancy does not appear to be harmful for long-term prognosis of MS. However, ovarian aging may contribute to disability progression in women with MS. Here, we review sex effects across the lifespan in women with MS, including the effect of sex on MS susceptibility, effects of pregnancy on MS disease activity, and management strategies around pregnancy, including risks associated with DMT use before and during pregnancy, and while breastfeeding. We also review reproductive aging and sexual dysfunction in women with MS.

Management of Demyelinating Disorders in Pregnancy

Multiple sclerosis (MS) and neuromyelitis optica (NMO) are chronic inflammatory demyelinating disorders of the central nervous system that often affect women during childbearing years. Therefore, issues of conception, pregnancy, and delivery are of significant importance to patients and treating physicians. The current review provides updated information regarding the effects of pregnancy on MS and NMO, as well as the available safety data on immunomodulatory MS therapies for pregnant and lactating women. Management issues of women with MS and NMO during conception, gestation, and the postpartum period also are addressed.

Pregnancy and multiple sclerosis: Clinical effects across the lifespan

Multiple sclerosis (MS) is commonly diagnosed in women of childbearing age. Having a greater understanding of the effects of pregnancy on the course of MS will lead to improved family-planning counselling for women. We found well-established evidence for a protective effect of pregnancy on relapse occurrence in historical cohorts. More recent studies suggest that the protective effect of pregnancy against relapse may be lost in those women with more active disease treated with high efficacy therapies. Furthermore, a strong body of evidence suggests that gravidity after diagnosis of MS does not lead to worse long-term outcomes. More contentious however, is whether pregnancy can delay a first episode of demyelination or a confirmed diagnosis of MS. This review provides a detailed analysis of the literature relating to the clinical effects of pregnancy on MS outcomes across a woman's reproductive lifespan.

Autoimmune Disease in Women: Endocrine Transition and Risk Across the Lifespan

Women have a higher incidence and prevalence of autoimmune diseases than men, and 85% or more patients of multiple autoimmune diseases are female. Women undergo sweeping endocrinological changes at least twice during their lifetime, puberty and menopause, with many women undergoing an additional transition: pregnancy, which may or may not be accompanied by breastfeeding. These endocrinological transitions exert significant effects on the immune system due to interactions between the hormonal milieu, innate, and adaptive immune systems as well as pro- and anti-inflammatory cytokines, and thereby modulate the susceptibility of women to autoimmune diseases. Conversely, pre-existing autoimmune diseases themselves impact endocrine transitions. Concentration-dependent effects of estrogen on the immune system; the role of progesterone, androgens, leptin, oxytocin, and prolactin; and the interplay between Th1 and Th2 immune responses together maintain a delicate balance between host defense, immunological tolerance and autoimmunity. In this review, multiple autoimmune diseases have been analyzed in the context of each of the three endocrinological transitions in women. We provide evidence from human epidemiological data and animal studies that endocrine transitions exert profound impact on the development of autoimmune diseases in women through complex mechanisms. Greater understanding of endocrine transitions and their role in autoimmune diseases could aid in prediction, prevention, and cures of these debilitating diseases in women.

An overview of pregnancy-related issues in patients with multiple sclerosis

Although pregnancy in women with multiple sclerosis (MS) is not generally considered high risk, there are some associated therapeutic challenges. The pregnancy-associated reduction in the relapse rate, especially in the third trimester, is followed by a sharp increase in the first few months postpartum. Nevertheless, retrospective evidence for pregnant women with and without MS followed for up to 10 years indicates that pregnancy has no perceptible effect on long-term disease course or disability progression. Likewise, MS has no apparent effects on the pregnancy course or fetal outcomes. All disease-modifying therapies (DMTs) have potential adverse effects on fertility and pregnancy outcomes, but the level of risk varies amongst agents. There is some support for continued use of interferon-β and glatiramer acetate throughout pregnancy to reduce the risk of relapse. Use of DMTs during breastfeeding is best avoided if possible. Close evaluation of drug safety information is imperative when managing women with MS who are pregnant or wish to become pregnant. Decision-making should be a shared experience between patient and physician, and the approach must be individualized for each patient.

Factors associated with onset, relapses or progression in multiple sclerosis: A systematic review

Multiple sclerosis (MS) is a chronic disease of the central nervous system with an unidentified etiology. We systematically reviewed the literature on the possible risk factors associated with MS disease onset, relapses and progression from 1960 to 2012 by accessing six databases and including relevant systematic reviews, meta-analyses, case-control or cohort studies. The focus was on identifying modifiable risk factors. Fifteen systematic reviews and 169 original articles were quality assessed and integrated into a descriptive review. Best evidence, which included one or more prospective studies, suggested that lower exposure to sunlight and/or lower serum vitamin D levels were associated with an increased risk of developing MS onset and subsequent relapses, but a similar quality of evidence was lacking for disease progression. Prospective studies indicated that cigarette smoking may increase the risk of MS as well as accelerate disease progression, but whether smoking altered the risk of a relapse was largely unknown. Infections were implicated in both risk of developing MS and relapses, but data for progression were lacking. Specifically, exposure to the Epstein-Barr virus, particularly if this manifested as infectious mononucleosis during adolescence, was associated with increased MS risk. Upper respiratory tract infections were most commonly associated with an increase in relapses. Relapse rates typically dropped during pregnancy, but there was no strong evidence to suggest that pregnancy itself altered the risk of MS or affected long-term progression. Emerging research with the greatest potential to impact public health was the suggestion that obesity during adolescence may increase the risk of MS; if confirmed, this would be of major significance.

Offspring Number Does Not Influence Reaching the Disability's Milestones in Multiple Sclerosis: A Seven-Year Follow-Up Study

OBJECTIVES

Data on pregnancy long-term effects on multiple sclerosis (MS) course are still controversial; whether experiencing more than one pregnancy exposes one to risk of the disability's accrual is still unknown. We investigated differences existing in terms of disability progression among women with MS (wwMS) who had one or more children after their MS onset.

METHODS

Monoparous and multiparous wwMS were enrolled from the Catania MS Center, Italy, in a monocenter retrospective study. A Cox proportional hazards model was used to examine the effect of the number of parities on time from MS disease onset to EDSS 4.0 and 6.0. The study protocol was approved by the local Ethical Committee.

RESULTS

During the seven years of observation, 32.1% and 23.2% of the monoparous group reached expanded disability disease status (EDSS) 4.0 and 6.0 respectively, compared to 13.3% and 3.3% of the multiparous group (p = 0.057 and p = 0.017; respectively). The Kaplan-Meier curve analysis showed no statistically-significant differences between the two groups in reaching the two milestones. The multiparous group showed a longer time to reach the EDSS 4.0 (3.5 vs. 2.6 years, log-rank 0.57, p = 0.45). The Cox regression analysis showed that the EDSS at the time of first pregnancy (Exp(B) 9.4, CI 4.5-19.7, p< 0.001) and the time from MS onset to first pregnancy (Exp(B) 0.96, CI = 0.93-0.98, p < 0.05) were significant predictors of reaching the EDSS 4.0, whereas a model including only the EDSS one year after the first pregnancy significantly predicted (Exp(B) value of 6.4, CI 2.6-15.4, p < 0.001) the reaching of EDSS 6.0.

CONCLUSIONS

Our results suggest that experiencing more than one pregnancy could not convey a different clinical outcome in wwMS. Further research is needed to confirm our results.

Fertility, pregnancy and childbirth in patients with multiple sclerosis: impact of disease-modifying drugs

In recent decades, pregnancy-related issues in multiple sclerosis (MS) have received growing interest. MS is more frequent in women than in men and typically starts during child-bearing age. An increasing number of disease-modifying drugs (DMDs) for the treatment of MS are becoming available. Gathering information on their influences on pregnancy-related issues is of crucial importance for the counselling of MS patients. As for the immunomodulatory drugs (interferons and glatiramer acetate), accumulating evidence points to the relative safety of pregnancy exposure in terms of maternal and foetal outcomes. In case of higher clinical disease activity before pregnancy, these drugs could be continued until conception. As for the 'newer' drugs (fingolimod, natalizumab, teriflunomide, dimethyl fumarate and alemtuzumab), the information is more limited. Whereas fingolimod and teriflunomide are likely associated with an increased risk of foetal malformations, the effects of natalizumab, dimethyl fumarate and alemtuzumab still need to be ascertained. This article provides a review of the available information on the use of DMDs during pregnancy, with a specific focus on fertility, foetal development, delivery and breast-feeding.

Parity is associated with a longer time to reach irreversible disability milestones in women with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) frequently affects women of childbearing age. While short-term effects of pregnancy on MS course are well-known, whether pregnancy may influence long-term disability progression is debated.

METHODS

A two-centre retrospective study to investigate long-term effect of pregnancy on disability was performed in a population of MS women. Survival analyses and multivariate Cox proportional regression models (including early predictors of MS severity and exposure to disease-modifying treatments) were performed to compare time to reach well-established disability milestones in nulliparous women and in those with pregnancies after MS onset ('parous'). Women with pregnancies before MS onset were excluded from analyses as they represent a heterogeneous group.

RESULTS

Data about 445 women (261 nulliparous, 184 'parous') were analysed. A longer time to reach Expanded Disability Status Scale (EDSS) 4.0 and 6.0 was observed in parous women; Cox regression models revealed a lower risk for 'parous' than nulliparous women in reaching EDSS 4.0 and 6.0 (HR = 0.552, p = 0.008 and HR = 0.422, p = 0.012 respectively).

CONCLUSION

Our findings suggest that pregnancy after MS onset is associated with a slower long-term disability progression. Whether this represents a biological/immunological effect, or reflects a higher propensity toward childbearing in women with milder disease, it remains uncertain deserving further investigations.

Postpartum relapses increase the risk of disability progression in multiple sclerosis: the role of disease modifying drugs

OBJECTIVE

To assess relapses, disability progression and the role of disease modifying drugs (DMDs) in the year after delivery in women with multiple sclerosis (MS).

METHODS

We prospectively followed-up pregnancies occurring between 2002 and 2008 in women with MS, recruited from 21 Italian MS centres. The risk of relapses and disability progression in the year after delivery was assessed using time-dependent Cox regression analysis.

RESULTS

350 out of 423 pregnancies were assessed (pregnancies not resulting in live birth and with a postpartum follow-up period shorter than 1 year were excluded from the analysis). 148 patients (42.3%) had at least one relapse in the year after delivery. An Expanded Disability Status Scale (EDSS) score at conception ≥2.0 (HR=1.4; 95% CI 1.1 to 2.0; p=0.046) and a higher number of relapses before (HR=1.5; 95% CI 1.2 to 1.8; p<0.001) and during pregnancy (HR=2.3; 95% CI 1.6 to 3.4; p<0.001) were related to a higher risk of postpartum relapses. On the contrary, early DMD resumption after delivery marginally reduced the risk of postpartum relapses (HR=0.7, 95% CI 0.4 to 1.0; p=0.079). Moreover, 44/338 women progressed by at least one point on the EDSS. Disability progression was associated with a higher number of relapses before (HR=1.4, 95% CI 1.1 to 1.9; p=0.047) and after delivery (HR=2.7, 95% CI 1.4 to 5.2; p=0.002).

CONCLUSIONS

Our findings show an increased risk of postpartum relapses and disability accrual in women with higher disease activity before and during pregnancy. Since it may reduce the risk of postpartum relapses, early DMD resumption should be encouraged, particularly in patients with more active disease.

Multiple sclerosis and pregnancy: therapeutic considerations

For women with multiple sclerosis (MS) who become pregnant, the risks and benefits of ongoing therapy for the health of both the mother and the fetus must be carefully considered. Based on a literature review and our MS center's standard practices, we provide guidance to aid clinical decision making in the absence of clear evidence-based clinical practice guidelines. Women seeking to achieve pregnancy should generally discontinue disease-modifying therapy use prior to attempting conception. For example, the immunosuppressant mitoxantrone is teratogenic and should be prescribed only with the assurance of effective contraception. Conception should be discouraged for patients on fingolimod, because of the limited information available on human pregnancy outcomes. Current evidence, including data from pregnancy registries for glatiramer acetate (GA), interferon beta-1a (IFNβ-1a), and natalizumab, has not shown specific patterns of malformations suggesting teratogenicity. Pregnancy registry data have not been published for IFNβ-1b. During breastfeeding, intravenous immunoglobulin and corticosteroids are generally safe and may be associated with a reduction in postpartum relapses; however, a washout period is recommended between corticosteroid administration and the resumption of breastfeeding. Clinical data on the use of IFNβ, GA, and natalizumab during lactation are limited. Mitoxantrone is contraindicated during breastfeeding, and fingolimod should be avoided in nursing mothers, because of a lack of data.

Gender issues in multiple sclerosis

Multiple sclerosis (MS) varies considerably in the way that it affects females and males. The prevalence of the disease is much greater in women and tends to follow a different clinical course than it follows in the affected male population. It is also well known that MS symptoms often are much less of a problem during pregnancy. This chapter discusses possible explanations for gender differences based on sex hormones as well as the effects of these hormones on cytokines and other factors that may influence the course of MS. Knowledge of these effects may hold some promise in other types of treatment for MS. Since MS is much more prevalent in women of child-bearing age, there are also implications for the use of disease-modifying agents as well as drugs and treatments that may be useful for treatment of MS. MS often causes symptoms of sexual dysfunction, but there may be effective treatment for many of these treatments.

Multiple sclerosis and pregnancy

Overall, evidence suggests the effect of pregnancy is at least neutral and possibly positive on the course of MS. The lack of effect MS has on pregnancy outcomes also is significant. In the end, pregnancy is an individual decision.Physicians, and in particular neurologists, play a key role in providing tools to assist women who are living with MS make the most appropriate decision concerning family planning for themselves and their families.

Pregnancy and multiple sclerosis

In this review, we summarize the available information on the short- and long-term effects of pregnancy on the course of multiple sclerosis (MS). Published studies that used established criteria for the diagnosis of MS were given more weight than studies in which the criteria for diagnosis were unstated or unclear. Population-based studies were emphasized more than clinic-based studies, unless the clinic base was well defined and thought to be reasonably representative of the MS population in the geographic area. For completeness, small studies were also included but weighted accordingly in our overall conclusions. Methodologic limitations and biases inherent in the study methods are discussed. We conclude that patients with relapsing MS have an increased risk of relapse during the initial 6-month postpartum period. This increased risk does not seem to have a detrimental effect on the rate of developing sustained disability. In fact, a full-term pregnancy may increase the time interval to reaching a common disability endpoint-walking with the aid of a cane or crutch--or to having a secondarily progressive course. Evidence indicates that pregnancy may alter T-lymphocyte functions and cause clinically relevant consequences. The specific biochemical mechanisms responsible for these observations, however, remain undefined. Because of limitations of current knowledge, our conclusions are tentative at best. The data are most applicable to patients with relapsing-remitting MS in its early stages. MS is an unpredictable disease and is only one of many factors that patients must consider when a pregnancy is contemplated.