title: Prostanoid excretion in incipient singleton and twin pregnancies.
abstract: OBJECTIVE
  Our purpose was to examine the urinary excretion of metabolites of prostacyclin, 6-keto-prostaglandin F(1 alpha) and 2,3-dinor-6-keto-prostaglandin F(1 alpha), and thromboxane A2, thromboxane B2 and 2,3-dinor-thromboxane B2, in early twin and singleton pregnancies resulting from in vitro fertilization-embryo transfer.
  
  
  METHODS
  Overnight urine samples were obtained from 23 women at regular intervals for 20 weeks after embryo transfer. Prostanoids were measured by high-pressure liquid chromatography-radioimmunoassay.
  
  
  RESULTS
  All prostanoids, most markedly 6-keto-prostaglandin F(1 alpha) and 2,3-dinor-6-keto-prostaglandin F(1 alpha), increased in both singleton and twin pregnancies. This resulted in an increased ratio of prostacyclin over thromboxane A2 both in the dinor compounds (from 1.3 to 2.8) and the total metabolites (from 1.7 to 3.5). No marked differences were observed between twin and singleton pregnancies.
  
  
  CONCLUSIONS
  Twin and singleton pregnancies show a similar increase in the prostacyclin to thromboxane A2 ratio in the first half of pregnancy.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproduction, Leiden University Hospital, The Netherlands.
authors.forename: R M
authors.initials: RM
authors.lastname: van der Weiden
authors.forename: F M
authors.initials: FM
authors.lastname: Helmerhorst
authors.forename: M J
authors.initials: MJ
authors.lastname: Keirse
mesh_terms: D015121:6-Ketoprostaglandin F1 alpha / Q000031:analogs & derivatives / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D009994:Osmolar Concentration; D011247:Pregnancy / Q000652:urine*; D011272:Pregnancy, Multiple / Q000652:urine*; D011453:Prostaglandins / Q000652:urine*; D011863:Radioimmunoassay; D013928:Thromboxane A2 / Q000652:urine; D013929:Thromboxane B2 / Q000652:urine; D014427:Twins
chemical_list: D011453:Prostaglandins; D013929:Thromboxane B2; D013928:Thromboxane A2; D015121:6-Ketoprostaglandin F1 alpha; C028290:2,3-dinor-6-ketoprostaglandin F1alpha