title: Development of heart block in children of SSA/SSB-autoantibody-positive women is associated with maternal age and displays a season-of-birth pattern.
abstract: OBJECTIVE
  Congenital heart block may develop in the fetuses of Ro/SSA-positive and La/SSB-positive mothers. Recurrence rates of only 10-20% despite persisting maternal antibodies indicate that additional factors are critical for the establishment of heart block. The authors investigated the influence of other maternal and fetal factors on heart block development in a Swedish population-based cohort.
  
  
  METHODS
  The influence of fetal gender, maternal age, parity and time of birth on heart block development was analysed in 145 families, including Ro/La-positive (n=190) and Ro/La-negative (n=165) pregnancies.
  
  
  RESULTS
  There was a recurrence rate of 12.1% in Ro/La-positive women, and no recurrence in Ro/La-negative women. Fetal gender and parity did not influence the development of heart block in either group. Maternal age in Ro/La-positive pregnancies with a child affected by heart block was, however, significantly higher than in pregnancies resulting in babies without heart block (p<0.05).Seasonal timing of pregnancy influenced the outcome. Gestational susceptibility weeks 18-24 occurring during January-March correlated with a higher proportion of children with heart block and lower vitamin D levels during the same period in a representative sample of Swedish women and a corresponding higher proportion of children with heart block born in the summer (p<0.02). Maternal age or seasonal timing of pregnancy did not affect the outcome in Ro/La-negative pregnancies.
  
  
  CONCLUSIONS
  This study identifies maternal age and seasonal timing of pregnancy as novel risk factors for heart block development in children of Ro/La-positive women. These observations may be useful for counselling when pregnancy is considered.
authors.affiliation: Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Ambrosi
authors.forename: Stina
authors.initials: S
authors.lastname: Salomonsson
authors.forename: Håkan
authors.initials: H
authors.lastname: Eliasson
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Zeffer
authors.forename: Amanda
authors.initials: A
authors.lastname: Skog
authors.forename: Vijole
authors.initials: V
authors.lastname: Dzikaite
authors.forename: Gunnar
authors.initials: G
authors.lastname: Bergman
authors.forename: Eva
authors.initials: E
authors.lastname: Fernlund
authors.forename: Joanna
authors.initials: J
authors.lastname: Tingström
authors.forename: Elke
authors.initials: E
authors.lastname: Theander
authors.forename: Annika
authors.initials: A
authors.lastname: Rydberg
authors.forename: Thomas
authors.initials: T
authors.lastname: Skogh
authors.forename: Annika
authors.initials: A
authors.lastname: Öhman
authors.forename: Ulla
authors.initials: U
authors.lastname: Lundström
authors.forename: Mats
authors.initials: M
authors.lastname: Mellander
authors.forename: Ola
authors.initials: O
authors.lastname: Winqvist
authors.forename: Michael
authors.initials: M
authors.lastname: Fored
authors.forename: Anders
authors.initials: A
authors.lastname: Ekbom
authors.forename: Lars
authors.initials: L
authors.lastname: Alfredsson
authors.forename: Henrik
authors.initials: H
authors.lastname: Källberg
authors.forename: Tomas
authors.initials: T
authors.lastname: Olsson
authors.forename: Fredrik
authors.initials: F
authors.lastname: Gadler
authors.forename: Anders
authors.initials: A
authors.lastname: Jonzon
authors.forename: Ingrid
authors.initials: I
authors.lastname: Kockum
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Sonesson
authors.forename: Marie
authors.initials: M
authors.lastname: Wahren-Herlenius
mesh_terms: D000293:Adolescent; D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood*; D001327:Autoimmune Diseases / Q000453:epidemiology / Q000276:immunology; D001722:Birth Order; D002648:Child; D002675:Child, Preschool; D005191:Family Characteristics; D005260:Female; D006327:Heart Block / Q000151:congenital* / Q000453:epidemiology / Q000276:immunology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000276:immunology; D011297:Prenatal Exposure Delayed Effects; D012008:Recurrence; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D013548:Sweden / Q000453:epidemiology; D014807:Vitamin D / Q000097:blood; D055815:Young Adult
chemical_list: D000974:Antibodies, Antinuclear; C035356:SS-A antibodies; C035357:SS-B antibodies; D014807:Vitamin D