title: Ovarian function and the return of potential fertility in lactating women.
abstract: OBJECTIVE
  Indices of ovarian function and potential fertility have been studied in fully lactating women from the sixth week post-partum to the start of the second menstrual period.
  
  
  METHODS
  Thirty-four women entered the study and 17 (50%) continued until the first menses. Of these, 16 continued until the second menses. The median time from delivery to day 1 of the first menses was 202 days (range, 85 to 668 days).
  
  
  METHODS
  The concentrations of estrone glucuronide (EG) and pregnanediol glucuronide in daily samples of early morning urine were measured by time-resolved fluoroimmunoassay and LH by an immunoradiometric assay. Algorithms were used retrospectively to determine the rise and peak days of all three metabolites.
  
  
  RESULTS
  Three cycles were studied relative to day 1 of first menses: (1) premenstrual (days -60 to -31), (2) menstrual (days -30 to -1), and (3) postmenstrual (days 1 to 56). Follicular development occurred in 53%, 100% and 100% of the dated cycles respectively. A peak of LH occurred in 6%, 75% and 80% of cycles, respectively. A period of potential fertility occurred in 11/17 (65%) and 13/16 (81%) of cycles (2) and (3), respectively. The proportion of potentially fertile cycles was higher after the first menses, and after 6 months had elapsed postpartum.
  
  
  CONCLUSIONS
  A test based on the measurement of EG and used prospectively predicted 13/15 (85%) of the periods of potential fertility during the postmenstrual cycle.
authors.affiliation: Department of Obstetrics and Gynaecology, University College Hospital, London, U.K.
authors.forename: A M
authors.initials: AM
authors.lastname: Mills
authors.forename: C P
authors.initials: CP
authors.lastname: O'Reilly
authors.forename: W P
authors.initials: WP
authors.lastname: Collins
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D004970:Estrone / Q000652:urine; D005260:Female; D005298:Fertility / Q000502:physiology*; D015200:Fluoroimmunoassay; D005965:Glucuronates / Q000652:urine; D006801:Humans; D015592:Immunoradiometric Assay; D007774:Lactation / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D008598:Menstruation; D010053:Ovary / Q000502:physiology*; D011276:Pregnanediol / Q000652:urine; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D005965:Glucuronates; D004970:Estrone; D007986:Luteinizing Hormone; D011276:Pregnanediol