title: Psychotic illness in first-time mothers with no previous psychiatric hospitalizations: a population-based study.
abstract: BACKGROUND
  Psychotic illness following childbirth is a relatively rare but severe condition with unexplained etiology. The aim of this study was to investigate the impact of maternal background characteristics and obstetric factors on the risk of postpartum psychosis, specifically among mothers with no previous psychiatric hospitalizations.
  
  
  RESULTS
  We investigated incidence rates and potential maternal and obstetric risk factors of psychoses after childbirth in a national cohort of women who were first-time mothers from 1983 through 2000 (n = 745,596). Proportional hazard regression models were used to estimate relative risks of psychoses during and after the first 90 d postpartum, among mothers without any previous psychiatric hospitalization and among all mothers. Within 90 d after delivery, 892 women (1.2 per 1,000 births; 4.84 per 1,000 person-years) were hospitalized due to psychoses and 436 of these (0.6 per 1,000 births; 2.38 per 1,000 person-years) had not previously been hospitalized for any psychiatric disorder. During follow-up after the 90 d postpartum period, the corresponding incidence rates per 1,000 person-years were reduced to 0.65 for all women and 0.49 for women not previously hospitalized. During (but not after) the first 90 d postpartum the risk of psychoses among women without any previous psychiatric hospitalization was independently affected by: maternal age (35 y or older versus 19 y or younger; hazard ratio 2.4, 95% confidence interval [CI] 1.2 to 4.7); high birth weight (> or = 4,500 g; hazard ratio 0.3, 95% CI 0.1 to 1.0); and diabetes (hazard ratio 0).
  
  
  CONCLUSIONS
  The incidence of psychotic illness peaks immediately following a first childbirth, and almost 50% of the cases are women without any previous psychiatric hospitalization. High maternal age increases the risk while diabetes and high birth weight are associated with reduced risk of first-onset psychoses, distinctly during the postpartum period.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. unnurav@hi.is
authors.forename: Unnur
authors.initials: U
authors.lastname: Valdimarsdóttir
authors.forename: Christina M
authors.initials: CM
authors.lastname: Hultman
authors.forename: Bernard
authors.initials: B
authors.lastname: Harlow
authors.forename: Sven
authors.initials: S
authors.lastname: Cnattingius
authors.forename: Pär
authors.initials: P
authors.lastname: Sparén
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001724:Birth Weight; D015331:Cohort Studies; D048909:Diabetes Complications / Q000150:complications; D004967:Estrogens / Q000502:physiology; D005260:Female; D006760:Hospitalization; D006778:Hospitals, Psychiatric; D006801:Humans; D015994:Incidence; D001523:Mental Disorders / Q000453:epidemiology* / Q000209:etiology; D049590:Postpartum Period; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
chemical_list: D004967:Estrogens