title: Resumption of ovarian function during lactational amenorrhoea in breastfeeding women with polycystic ovarian syndrome: endocrine aspects.
abstract: BACKGROUND
  The aim of this study was to evaluate the changes in gonadotrophin concentrations and the dynamics of the episodic fluctuations of circulating LH during night-time, in fully breastfeeding normal women and in those with polycystic ovarian syndrome (PCOS) during lactational amenorrhoea and after weaning, in order to provide insights into the onset of this syndrome. Additionally, ovarian activity was evaluated by ultrasound examination and steroid concentrations.
  
  
  METHODS
  Twelve lactating PCOS (LPCOS) women and six normal lactating (NL) women of similar age were selected. On the 4th and 8th week postpartum (PP) and eight weeks after weaning, blood samples were collected every 10 min (10.00--20.00h). Gonadotrophin concentrations were determined in all samples. Steroid hormones were measured in one fasting sample and ovarian morphology was assessed by ultrasound.
  
  
  RESULTS
  On the 8th week PP, LH pulse frequency was higher and FSH concentrations were lower in LPCOS women compared with NL women, and steroid hormone concentrations remained low, except for androstenedione which was higher in LPCOS patients. After weaning, similar differences were observed between both groups. PCOS patients also showed enlarged ovaries with a PCOS pattern in the three study periods.
  
  
  CONCLUSIONS
  The enlarged ovaries associated with higher androstenedione concentrations suggest that PCOS is a primary ovarian defect, making it difficult to establish if the abnormal LH pattern observed in these women is primary or secondary to the ovarian dysfunction.
authors.affiliation: Division of Endocrinology, Department of Internal Medicine, School of Medicine, University of Chile, Santiago, Chile. tsir@entelchile.net
authors.forename: T
authors.initials: T
authors.lastname: Sir-Petermann
authors.forename: L
authors.initials: L
authors.lastname: Devoto
authors.forename: M
authors.initials: M
authors.lastname: Maliqueo
authors.forename: P
authors.initials: P
authors.lastname: Peirano
authors.forename: S E
authors.initials: SE
authors.lastname: Recabarren
authors.forename: L
authors.initials: L
authors.lastname: Wildt
mesh_terms: D000328:Adult; D000568:Amenorrhea / Q000503:physiopathology*; D000735:Androstenedione / Q000097:blood; D002940:Circadian Rhythm; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007774:Lactation; D007986:Luteinizing Hormone / Q000097:blood*; D010053:Ovary / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011085:Polycystic Ovary Syndrome / Q000503:physiopathology*; D049590:Postpartum Period; D011388:Prolactin / Q000097:blood; D014463:Ultrasonography; D014886:Weaning
chemical_list: D000735:Androstenedione; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone