Juvenile onset arthritis and pregnancy outcome: a population-based cohort study

Patterns of reproductive health in inflammatory rheumatic diseases and other immune-mediated diseases: a nationwide registry study

OBJECTIVES

Rheumatic diseases may impair reproductive success and pregnancy outcomes, but systematic evaluations across diseases are lacking. We conducted a nationwide cohort study to examine the impact of rheumatic diseases on reproductive health measures, comparing the impacts with those of other immune-mediated diseases (IMDs).

METHODS

Out of all of the 5 339 804 Finnish citizens, individuals born 1964-1984 and diagnosed with any of the 19 IMDs before age 30 (women) or 35 (men) were matched with 20 controls by birth year, sex, and education. We used data from nationwide health registers to study the impact of IMDs on reproductive health measures, such as reproductive success and, for women, ever having experienced adverse maternal and perinatal outcomes.

RESULTS

Several of the rheumatic diseases, particularly SLE, JIA, and seropositive RA, were associated with higher rates of childlessness and fewer children. The risks for pre-eclampsia, newborns being small for gestational age, preterm delivery, non-elective Caesarean sections, and need of neonatal intensive care were increased in many IMDs. Particularly, SLE, SS, type 1 diabetes, and Addison's disease showed >2-fold risks for some of these outcomes. In most rheumatic diseases, moderate (1.1-1.5-fold) risk increases were observed for diverse adverse pregnancy outcomes, with similar effects in IBD, celiac disease, asthma, ITP, and psoriasis.

CONCLUSION

Rheumatic diseases have a broad impact on reproductive health, with effects comparable with that of several other IMDs. Of the rheumatic diseases, SLE and SS conferred the largest risk increases on perinatal adverse event outcomes.

A population-based study of caesarean section in women with juvenile idiopathic arthritis

Objectives

The literature on delivery methods in women with JIA is limited. Active inflammation is a risk factor for caesarean section (CS) in other arthritic diseases. A CS entails a higher risk for complications than vaginal delivery and restricted physical activity in the first weeks after birth. Our objective was to explore a possible association of inflammatory active disease and the proportion of CS in women with JIA.

Methods

Data from the Norwegian nationwide observational register RevNatus were linked with data from the Medical Birth Registry of Norway (MBRN). Cases comprised singleton births in women with JIA (n = 196) included in RevNatus from 2010 to 2019. Singleton births registered in the MBRN during the same period of time, excluding births in mothers with rheumatic inflammatory diseases, served as population controls (n = 575 798).

Results

CS was more frequent in women with JIA (20.4%) and in the subgroup of women with inflammatory active JIA (30.0%) than in population controls (15.6%). Women with active JIA had a risk for elective CS similar to population controls [risk difference 2.3% (95% CI -2.5, 12.9)] and a higher risk for emergency CS [risk difference 14.0% (95% CI 4.3, 27.4)] compared with population controls.

Conclusion

Women with active JIA had a higher risk for emergency CS, but not elective CS, compared with population controls.

Immunology of pregnancy and reproductive health in autoimmune rheumatic diseases. Update from the 11th International Conference on Reproduction, Pregnancy and Rheumatic Diseases

Autoimmune rheumatic diseases (ARD) can affect women and men during fertile age, therefore reproductive health is a priority issue in rheumatology. Many topics need to be considered during preconception counselling: fertility, the impact of disease-related factors on pregnancy outcomes, the influence of pregnancy on disease activity, the compatibility of medications with pregnancy and breastfeeding. Risk stratification and individualized treatment approach elaborated by a multidisciplinary team minimize the risk of adverse pregnancy outcomes (APO). Research has been focused on identifying biomarkers that can be predictive of APO. Specifically, preeclampsia and hypertensive disorders of pregnancy tend to develop more frequently in women with ARD. Placental insufficiency can lead to intrauterine growth restriction and small-for-gestational age newborns. Such APO have been shown to be associated with maternal disease activity in different ARD. Therefore, a key message to be addressed to the woman wishing for a pregnancy and to her family is that treatment with compatible drugs is the best way to ensure maternal and fetal wellbeing. An increasing number of medications have entered the management of ARD, but data about their use in pregnancy and lactation are scarce. More information is needed for most biologic drugs and their biosimilars, and for the so-called small molecules, while there is sufficient evidence to recommend the use of TNF inhibitors if needed for keeping maternal disease under control. Other issues related to the reproductive journey have emerged as "unmet needs", such as sexual dysfunction, contraception, medically assisted reproduction techniques, long-term outcome of children, and they will be addressed in this review paper. Collaborative research has been instrumental to reach current knowledge and the future will bring novel insights thanks to pregnancy registries and prospective studies that have been established in several Countries and to their joint efforts in merging data.

Pregnancy in juvenile idiopathic arthritis: maternal and foetal outcome, and impact on disease activity

Objective:

This retrospective cohort study describes the modulation of disease activity during gestation and in the year following delivery as well as maternal and neonatal outcomes in a monocentric cohort of women with juvenile idiopathic arthritis (JIA).

Methods:

Disease activity was assessed using DAS28-CRP before conception and every 3 months during pregnancy and in the first year postpartum. The risk of complicated pregnancies was measured applying a generalized estimating equation model. Changes in disease activity during gestation and in the first year postpartum were assessed in a linear mixed model for repeated measures.

Results:

Thirty-one women (49 pregnancies) with persisting JIA and at least one conception were enrolled. Adjusted DAS28-CRP levels remained stable from preconception through the first trimester, but increased significantly in the second and decreased not significantly in the third. In the postpartum, adjusted disease activity peaked at 3 months after delivery, stabilized at 6 months to decrease at 1 year, although not significantly. Preconceptional DAS28-CRP and number of biological drugs predicted disease activity fluctuation during gestation. The number of biological drugs and the length of gestational exposure to biologics significantly predicted pregnancy morbidity. In particular, JIA women had a higher probability of preterm delivery compared with healthy and disease controls. Adjusted for breastfeeding and DAS28-CRP score in the third trimester, postconceptional exposure to biologics was inversely related with disease activity in the postpartum: the longer the patient continued treatment, the lower the probability of experiencing an adverse pregnancy outcome.

Conclusion:

These data offer novel insights on how treatment affects disease activity during pregnancy and postpartum as well as obstetric outcomes in women with JIA.

Pregnancy outcomes in relation to disease activity and anti-rheumatic treatment strategies in women with rheumatoid arthritis

OBJECTIVES

To explore the association of maternal rheumatoid arthritis (RA) to pregnancy outcomes, especially preterm birth (PTB) and small for gestational age (SGA), in relation to disease activity and anti-rheumatic treatment before and during pregnancy.

METHODS

By linking prospective clinical rheumatology registers (CRR) in Sweden (SRQ) and Denmark (DANBIO) with medical birth registers, we identified 1,739 RA-pregnancies and 17 390 control-pregnancies (matched 1:10 on maternal age, birth year, parity) with delivery 2006-2018. Disease activity (DAS28, CRP, HAQ-score) and anti-rheumatic treatment nine months before and during pregnancy were identified through CRR and prescribed drug registers. Using logistic regression, we estimated adjusted odds ratios (aOR) with 95% confidence intervals (CI) for PTB and SGA overall and stratified by disease activity and anti-rheumatic treatment before and during pregnancy, adjusting for maternal characteristics.

RESULTS

We found increased aOR of PTB (1.92, 1.56-2.35) and SGA (1.93, 1.45-2.57) in RA-pregnancies vs control-pregnancies. For RA-pregnancies with DAS28-CRP ≥ 4.1 vs < 3.2 during pregnancy, aOR was 3.38 (1.52-7.55) for PTB and 3.90 (1.46-10.4) for SGA. Use of oral corticosteroids (yes/no) during pregnancy resulted in an aOR of 2.11 (0.94-4.74) for PTB. Corresponding figure for biologics was 1.38 (0.66-2.89). Combination therapy, including biologics before pregnancy, was a marker of increased risk of both PTB and SGA.

CONCLUSION

During pregnancy, disease activity rather than treatment seems to be the most important risk factor for PTB and SGA in RA. Women with RA should be carefully monitored during pregnancy, especially if they have moderate to high disease activity or/and are treated with extensive anti-rheumatic treatment.

The Impact of Pediatric Rheumatic Diseases on Sexual Health, Family Planning, and Pregnancy

A comprehensive review of reproductive health subtopics, including sexual intercourse, romantic relationships, contraception, sexually transmitted infections, pregnancy, and infertility, as they pertain to patients with pediatric rheumatic diseases and those who care for them.

Pregnancy outcomes in women with psoriatic arthritis with respect to presence and timing of antirheumatic treatment

OBJECTIVE

To evaluate pregnancy outcomes in relation to antirheumatic treatment before and during pregnancy as a proxy of disease severity in PsA-pregnancies as compared to non-PsA-pregnancies.

METHODS

Swedish nationwide register-based cohort study of 921 PsA- pregnancies and 9210 non-PSA-pregnancies (matched 1:10 on maternal age, year, and parity) 2007-2017. We estimated adjusted odds ratios (aOR) overall and stratified by presence, timing, and type of antirheumatic treatment. Adjustments were made for BMI, smoking, educational level and country of birth. The outcome preterm birth was also stratified by parity.

RESULTS

Women with PsA vs. non-PsA-pregnancies were more obese, more often smokers and had a diagnosis of pre-gestational hypertension and diabetes more often. Increased risks in PsA vs. non-PsA-pregnancies were foremost preterm birth (aOR 1.69, 95% CI 1.27-2.24) and cesarean delivery, (aOR 1.77, 95% CI 1.43-2.20 for elective and aOR 1.42, 95% CI 1.10-1.84 for emergency cesarean delivery). The risks differed with presence, timing, and type of antirheumatic treatment with the most increased risks in PsA-pregnancies (vs. non-PsA) with antirheumatic treatment during pregnancy, aOR preterm birth; 2.30, 95% CI 1.49-3.56. Corresponding aOR for biologics exposed PsA-pregnancies was 4.49, 95% CI 2.60-7.79. Risk of preterm birth was primarily increased in first pregnancies.

CONCLUSION

In comparison with non-PsA-pregnancies risks of preterm birth and cesarean delivery were mostly increased in those exposed to antirheumatic treatment during pregnancy, especially biologics. As parity influences the risk of preterm birth in PsA pregnancies special attention to first pregnancies is warranted. Women with PsA, should receive individualized monitoring during pregnancy.

Acute liver failure in Still's disease relapse during pregnancy: case report and discussion of a possible trigger role of DILI

BACKGROUND

Still's disease is a rare systemic inflammatory disease with frequent but generally mild liver involvement. The most common cause of acute liver failure in western countries is drug-induced liver injury, while it has rarely been reported in subjects suffering from Still's disease.

CASE PRESENTATION

We report a case of a young woman presenting with SD reactivation in pregnancy and acute liver failure after delivery with a possible triggering role of drug induced liver injury.

CONCLUSIONS

The prompt recognition of Still's disease reactivation allowed early introduction of steroid therapy and resolution of the clinical picture. We discuss potential factors precipitating ALF in this case, and implications for the diagnosis and management of such patients.

Vaginal microbiota in pregnant women with inflammatory rheumatic and inflammatory bowel disease: A matched case-control study

BACKGROUND

Rheumatic diseases and vaginal infections both increase the risk of preterm birth. It is unclear whether pregnant women with rheumatic disease are more likely to experience vaginal infections, which might potentially accumulate modifiable risk factors.

OBJECTIVE

In this study, we sought to evaluate the vaginal microbiota of pregnant women with inflammatory rheumatic and inflammatory bowel disease.

METHODS

A total of 539 asymptomatic women with singleton pregnancy were routinely screened for an abnormal vaginal microbiota between 10 + 0 and 16 + 0 gestational weeks. Vaginal smears were Gram-stained and microscopically analysed. Those with inflammatory diseases (with or without immunomodulatory therapy) were assigned to the case group and matched in a 1:3 ratio to healthy pregnant controls.

RESULTS

Overall, an abnormal vaginal microbiota occurred more frequently among women of the case group, compared with those of the control group (33.8% vs 15.6%; 95% CI: 1.78-4.27, p < .001). In particular, Candida colonisation (22.3% vs 9.2%; 95% CI: 1.69-4.75, p < .001), but also bacterial vaginosis (14.9% vs 7.2%; 95% CI: 1.25-4.1, p = .006), occurred more often in the case than in the control group. No significant difference was found with regard to the occurrence of an abnormal vaginal microbiota between subgroups with and without immunomodulatory treatment (37.0% vs 27.1%; 95% CI: 0.29-1.35, p = .232).

CONCLUSION

Pregnant women with inflammatory rheumatic and inflammatory bowel disease are at risk for bacterial vaginosis and Candida colonisation, which might pose a risk for preterm birth. Prospective studies are needed to further evaluate the influence of autoimmune conditions and immunosuppressive therapy on the vaginal microbiota.

Disease course and obstetric outcomes of pregnancies in juvenile idiopathic arthritis: are there any differences among disease subtypes? A single-centre retrospective study of prospectively followed pregnancies in a dedicated pregnancy clinic

To study disease activity during pregnancy and obstetric outcomes in patients with juvenile idiopathic arthritis (JIA) upon different subsets and with focus on medication use. Retrospective observational study of 22 pregnancies in 16 JIA patients (95.5% Caucasian) who were followed between 2010 and 2018. Disease activity, flares and medications were recorded before conception, during each trimester and postpartum period. Pregnancies occurred in 10 (45.5%) oligoarticular extended (OLA-E), 6 (27.3%) in polyarticular (PLA), 4 in (18.2%) systemic (SYS), 1 (4.5%) in oligoarticular persistent (OLA-P) and 1 (4.5%) in enthesitis-related arthritis (ERA) JIA patients. The median age at disease diagnosis and at conception was 5.5 and 28 years (respectively). The median disease duration was 20 years. Nineteen (95%) pregnancies started in a period of stable disease remission. Among the 22 pregnancies, 20 ended with a live birth (90.9%). No spontaneous miscarriages occurred; two voluntary interruption of pregnancy were performed. There were 7 flares in 6/20 pregnancies (35%) and 8 flares (8/22, 36.4%) occurred in postpartum period, all of them in OLA-E and PLA patients. Seven patients (35%) were taking biological disease-modifying anti-rheumatic drugs (bDMARDs) at conception, and 6 of them stopped this treatment at positive pregnancy test. Five patients resumed bDMARDs either during pregnancy (3 exposed during the third trimester) or puerperium due to a flare. Four preterm deliveries (20%) were recorded, all in patients who had a flare during pregnancy. The preconception counselling should include the evaluation of disease subset, as OLA-E and PLA may flare more than other subsets, especially if bDMARDs are discontinued at positive pregnancy test. Continuation of bDMARDs during pregnancy should be considered to minimize the risk of adverse pregnancy outcomes, particularly preterm delivery. Key Points • In our cohort, all the flares during pregnancy and 75% of postpartum flares were observed in patients who withdrew bDMARDs and cDMARDs at the beginning of pregnancy. • Flares were observed only in PLA and OLA-E patients. • Preterm delivery occurred in 20% of the pregnancies; all of these patients had a disease flare during pregnancy.

Juvenile idiopathic arthritis and the gut microbiome: Where are we now?

In recent decades, because of advances in technology there has been an explosion of knowledge on how microbiome affects human health. In most chronic immune-inflammatory diseases, alterations in gut microbiome has been shown. The successful use of faecal microbial transplants for the treatment of clostridium difficile associated diarrhoea has also paved the way for novel therapies. Gut microbiome is affected by early life events like the mode of delivery, breast feeding, the use of antibiotics, etc. and that may have an indirect effect on the developing immune system as well as on the predisposition to juvenile idiopathic arthritis (JIA). Multiple studies have found altered gut microbiome in JIA though no single organism or microbial community has been found to be associated with JIA. In JIA, attempts to modify gut microbiome by using probiotics, exclusive enteral nutrition and other modalities have had variable success. The current review discusses the current data available on gut microbiome in different categories of JIA and how this knowledge can translate into new therapies.

Pregnancy outcomes and perinatal complications of Asian mothers with juvenile idiopathic arthritis - a case-control registry study

BACKGROUNDS

In order to provide juvenile idiopathic arthritis (JIA) patients with better pre-conceptional and prenatal counselling, we investigated the obstetrical and neonatal outcomes among women with Asian descent.

METHODS

Through the linkage of Taiwan National Health Insurance database and National Birth Registry, we established a population-based birth cohort in Taiwan between 2004 and 2014. In a case control study design, first children born to mothers with JIA are identified and matched with 5 non-JIA controls by maternal age and birth year. Conditional logistic regression was used to calculate odds ratios for maternal and neonatal outcomes crude and with adjustment.

RESULTS

Of the 2,100,143 newborn, 778 (0.037%) were born to JIA mothers. Among them, 549 first-born children were included in this research. Our result suggested that babies born to mothers with JIA were more likely to have low birth body weight, with an adjusted OR of 1.35(95% CI: 1.02 to 1.79) when compared to babies born to mothers without. No differences were observed in other perinatal complications between women with and without JIA including stillbirth, prematurity, or small for gestational age. The rate of adverse obstetrical outcomes such as caesarean delivery, preeclampsia, gestational diabetes, postpartum hemorrhage and mortality were also similar between the two.

CONCLUSIONS

Adverse obstetrical and neonatal outcomes were limited among Asian mothers with JIA. Intensive care may not be necessary for JIA mothers and their newborns.

Preterm birth phenotypes in women with autoimmune rheumatic diseases: a population-based cohort study

OBJECTIVE

To investigate preterm birth (PTB) phenotypes in women with different autoimmune rheumatic diseases in a large population-based cohort.

DESIGN

Retrospective cohort study.

SETTING

California, USA.

POPULATION

All live singleton births in California between 2007 and 2011 were analysed. Patients with autoimmune disease at delivery were identified by International Classification of Diseases, Ninth Revision , Clinical Modification (ICD-9-CM), codes for systemic lupus erythematosus (SLE), systemic sclerosis (SSc), rheumatoid arthritis (RA), polymyositis/dermatomyositis (DM/PM), and juvenile idiopathic arthritis (JIA).

METHODS

Maternally linked hospital and birth certificate records of 2 481 516 deliveries were assessed (SLE n = 2272, RA n = 1501, SSc n = 88, JIA n = 187, DM/PM n = 38). Multivariable Poisson regression models estimated the risk ratios (RRs) for different PTB phenotypes (relative to term deliveries) for each autoimmune disease compared with the general obstetric population, adjusting for maternal age, race/ethnicity, body mass index, smoking, education, payer, parity, and prenatal care.

MAIN OUTCOME MEASURES

Preterm birth (PTB) was assessed overall (20-36 weeks of gestation) and by subphenotype: preterm prelabour rupture of membranes (PPROM), spontaneous birth, or medically indicated PTB. The risk of PTB overall and for each phenotype was partitioned by gestational age: early (20-31 weeks of gestation) and late (32-36 weeks of gestation).

RESULTS

Risks for PTB were elevated for each autoimmune disease evaluated: SLE (RR 3.27, 95% CI 3.01-3.56), RA (RR 2.04, 95% CI 1.79-2.33), SSc (RR 3.74, 95% CI 2.51-5.58), JIA (RR 2.23, 95% CI 1.54-3.23), and DM/PM (RR 5.26, 95% CI 3.12-8.89). These elevated risks were observed for the majority of PTB phenotypes as well.

CONCLUSIONS

Women with systemic autoimmune diseases appear to have an elevated risk of various PTB phenotypes. Therefore, preconception counselling and close monitoring during pregnancy is crucial.

TWEETABLE ABSTRACT

This study found that women with systemic autoimmune diseases have an elevated risk of preterm birth phenotypes.

Maternal and infant pregnancy outcomes in women with psoriatic arthritis: a Swedish nationwide cohort study

OBJECTIVE

Studies on pregnancy outcomes in psoriatic arthritis (PsA) are scarce and typically of small size. Available studies have reported conflicting results. The aim of this study was to describe maternal and infant pregnancy outcomes among women with PsA compared with women without PsA.

DESIGN

Nationwide cohort study.

SETTING

Nationwide Swedish registers.

POPULATION

A total of 41 485 singleton pregnancies in 1997-2014, of which 541 pregnancies were identified with PsA exposure and 40 944 pregnancies were unexposed.

METHODS

By linkage of national health and population register data, we obtained information on individual pregnancies and compared outcomes among pregnancies with PsA and non-PsA pregnancies. Relative risks were estimated by odds ratios (ORs) with 95% CIs using a generalised linear regression model with generalised estimating equations. Adjustments were made for maternal factors and calendar year of birth.

MAIN OUTCOME MEASURES

Maternal and infant pregnancy outcomes.

RESULTS

Pregnancies to women with PsA had increased risks of preterm birth (adjusted OR 1.63; 95% CI 1.17-2.28), elective and emergency caesarean deliveries (adjusted OR 1.47; 95% CI 1.10-1.97 and adjusted OR 1.43; 95% CI 1.08-1.88, respectively) compared with non-PsA pregnancies. No increased risks were observed for pre-eclampsia, stillbirth or other infant outcomes apart from preterm birth.

CONCLUSION

The majority of women with PsA have uneventful pregnancies with respect to adverse outcomes. In the present study, we found increased risks of preterm birth and caesarean delivery compared with non-PsA pregnancies.

TWEETABLE ABSTRACT

Women with psoriatic arthritis have uneventful pregnancies but are at increased risk of preterm birth and caesarean delivery.

Pregnancy outcomes in DMARD-exposed patients with juvenile idiopathic arthritis—results from a JIA biologic registry

Objectives

To investigate the courses and outcomes of pregnancies involving JIA patients who were exposed to DMARDs.

Methods

In the Juvenile arthritis MTX/Biologics long-term Observation study, pregnant patients or male patients with pregnant partners were identified. Standardized patient interviews were conducted, and the course and outcome of pregnancy were assessed. Prospectively collected physician- and patient-reported data were also considered in the analysis.

Results

The study sample included 152 pregnancies in 98 women with JIA and 39 pregnancies involving 21 male patients as partners. The majority of patients had polyarticular-onset/-course JIA (61%). The average age of patients at first pregnancy was 24.1 (4.5) years, and their mean disease duration was 13.8 (5.9) years. Patients had been exposed to DMARDs for 9.5 (5.6) years, and 90% of these patients had received biologics before. Half of the pregnancies occurred during DMARD exposure, mostly with etanercept. Significant differences in pregnancy outcomes between DMARD-exposed and -unexposed pregnancies were not observed. Spontaneous abortion (13.1%) and congenital anomaly (3.6%) rates were not suggestive of increased risk compared with expected background rates. However, the rates of premature birth (12.3%) and caesarean section (37.7%) were slightly above those in the German birthing population. The disease activity of female patients remained relatively stable in pregnancy, with mean cJADAS-10 scores of 5.3, 7.1 and 5.6 in each trimester, respectively.

Conclusion

Young adults with JIA often become pregnant or become fathers of children while still being treated with DMARDs. Data suggest no increased risk of major adverse pregnancy outcomes.

Factors Associated With Preterm Delivery Among Women With Rheumatoid Arthritis and Women With Juvenile Idiopathic Arthritis

OBJECTIVE

Pregnant women with inflammatory arthritis may be at increased risk for preterm delivery (PTD), yet it is unclear what drives this risk. This aim of this prospective cohort study of pregnant women with rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), or healthier comparison women was to analyze the independent effects of maternal disease activity, medication use, and comorbid pregnancy conditions on PTD risk.

METHODS

Women were enrolled before 19 weeks completed gestation as part of the Organization of Teratology Information Specialists (OTIS) Autoimmune Disease in Pregnancy Project. Data on pregnancy events, medications, disease activity, and outcomes were obtained by maternal report and validated by medical records. Poisson regression with robust standard errors estimated risk ratios (RR), multivariable adjusted risk ratios (ARRs), and 95% confidence intervals (95% CIs).

RESULTS

A total of 657 women with RA, 170 with JIA, and 564 comparison women without autoimmune disease who delivered live born infants, from 2004 to 2017 were included for analysis. Both the RA and JIA groups had an increased risk of PTD versus the comparison group (RR 2.09 [95% CI 1.50-2.91] and RR 1.81 [95% CI 1.14-2.89], respectively). Active RA at enrollment (ARR 1.58 [95% CI 1.10-2.27]) and any time during pregnancy (ARR 1.52 [95% CI 1.06-2.18]) was associated with PTD. Corticosteroid use in every trimester was associated with an approximate 2- to 5-fold increased risk for PTD for both arthritis groups, independent of disease activity.

CONCLUSION

Women with RA and women with JIA are at increased risk for PTD. Maternal disease activity and corticosteroid use may contribute to some of this excess risk.

Disease activity assessment of rheumatic diseases during pregnancy: a comprehensive review of indices used in clinical studies

Pregnancy requires a special management in women with inflammatory rheumatic diseases (RDs), with the aim of controlling maternal disease activity and avoiding fetal complications. Despite the heterogeneous course of RDs during pregnancy, their impact on pregnancy largely relates to the extent of active inflammation at the time of conception. Therefore, accurate evaluation of disease activity is crucial for the best management of pregnant patients. Nevertheless, there are limitations in using conventional measures of disease activity in pregnancy, as some items included in these instruments can be biased by symptoms or by physiological changes related to pregnancy and the pregnancy itself may influence laboratory parameters used to assess disease activity. This article aims to summarize the current literature about the available instruments to measure disease activity during pregnancy in RDs. Systemic lupus erythematosus is the only disease with instruments that have been modified to account for several adaptations which might interfere with the attribution of signs or symptoms to disease activity during pregnancy. No modified-pregnancy indices exist for women affected by other RDs, but standard indices have been applied to pregnant patients. The current body of knowledge shows that the physiologic changes that occur during pregnancy need to be either adapted from existing instruments or developed to improve the management of pregnant women with RDs. Standardized instruments to assess disease activity during pregnancy would be helpful not only for clinical practice but also for research purposes.