title: [A study of two different routes of administration of micronized progesterone in assisted reproduction].
abstract: BACKGROUND
  Progesterone is almost completely absorbed after administration by oral route when its preparation is micronized, but, due to the important metabolic inactivation during the first hepatic pass, bioavailability of oral progesterone is notably poor reaching values lesser than 10%.
  
  
  OBJECTIVE
  To compare two different routes of administration of progesterone for luteal phase support in artificial insemination protocols.
  
  
  METHODS
  24 patients were randomly allocated in the 2 arms of the study, 200 mg/daily, vaginally or p.o. Plasma levels of progesterone were analyzed and ultrasound was performed to compare endometrium pattern and thickness.
  
  
  RESULTS
  No differences were found in terms of indication, semen parameters, number of preovulatory follicles and progesterone serum levels. Endometrial pattern and thickness were clinical and statistically better in group I as the pregnancy rate.
  
  
  CONCLUSIONS
  Taking in account our results we can argue that vaginal progesterone improve endometrial features favoring implantation and pregnancy rates without modifying progesterone serum levels.
authors.affiliation: Grupo IMER.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Gallardo Lozano
authors.forename: Patricia
authors.initials: P
authors.lastname: Ayón
authors.forename: Fernando
authors.initials: F
authors.lastname: Neuspiller
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007315:Insemination, Artificial; D011247:Pregnancy / Q000706:statistics & numerical data; D011374:Progesterone / Q000008:administration & dosage*; D011446:Prospective Studies
chemical_list: D011374:Progesterone