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SAT0533 Time Trends of Number of Pregnancies and Mean Birth Weight in Newborn of Patients with Specified Arthritis or Connective Tissue Disease
  1. M. Wallenius1,2,
  2. K. Å. Salvesen3,4,
  3. A. K. Daltveit5,6,
  4. J. F. Skomsvoll2
  2. 2Dept. of Neuroscience, Norwegian University of Science and Technology
  3. 3Dept. of Laboratory Medicine, Women’s and Child Health, Trondheim, Norway
  4. 4Dept. of Obstetrics and Gynecology, Clinical Sciences, Lund University, Lund, Sweden
  5. 5Department of Public Health and Primary Health Care, University of Bergen
  6. 6Medical Birth Registry of Norway, Division of Epidemiology, Norwegian Institute of Public Health, Bergen, Norway


Background Improving treatment options, pre-pregnancy councelling and interdisciplinary monitoring throughout pregnancy, make more rheumatic patients able to plan pregnancies.

Objectives To study time trends in number of pregnancies and mean birth weight in newborn of patients with specified arthritis (SA) and connective tissue diseases (CTD).

Methods The Medical Birth Registry of Norway (MBRN) comprises more than 2.2 million births 1967-2009. Women diagnosed with specified arthritis (SA) (rheumatoid arthritis, ankylosing spondylitis and juvenile idiopathic arthritis) and women diagnosed with connective tissue diseases (CTDs) (systemic lupus erythematosus, Sjøgren’s disease and mixed connective tissue disease) were included in the analyses. The diagnoses were based on registrations in MBRN according to International Classification of Diseases (ICD)-8 (1967-1998) and ICD-10 (1999-2009). Reference deliveries were all other deliveries 1967-2009 where the mother was not recorded with an inflammatory rheumatic disease. We studied the number of pregnancies in each decade. Further, mean birth weights for each decade were also analysed in multiple regression analyses with covariates for the mother’s age at delivery, gestational age, parity and gender of child. The level of statistical significance was set to <0.05.

Conclusions The number of pregnancies in women with SA or CTD has gradually increased during the last four decades. The low number of deliveries in the first decade may indicate that patients with inflammatory rheumatic diseases and especially CTD, were advised not to have children. Decreasing rates of spontaneous abortions has been reported after year 20001 and may indicate that more CTD patients have been able to accomplish pregnancy. Statistically significantly lower mean birth weight in children of CTD patients compared with references was present in all time periods. However, a trend of increasing mean birth weight was observed in CTD patients as well as references, and most pronounced among the patients. In SA patients statistically significantly lower mean birth weights were present until the end of 1999. After year 2000 the difference in birth weight was no longer statistically significant. There may be several reasons for the improving results over time. For arthritic patients treatment with TNF blockers the last decade may have lead to milder disease courses together with increasing knowledge about use of anti-inflammatory drugs in pregnancy and improved care taking of pregnant patients. The same improvement in treatment options has not been present for CTD patients.

References Lateef A, Petri M. Management of pregnancy in systemic lupus erythematosus. Nat Rev Rheumatol. 2012;8:710-8

Acknowledgements The Medical Birth Registry of Norway (data delivery)

The Liaison Committee between the Central Norway Regional Health Authority and NTNU (financial support)

Disclosure of Interest None Declared

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