title: Measurement of betamethasone concentration in maternal serum treated for fetal lung maturity; Is it feasible?
abstract: BACKGROUND
  The association between maternal serum concentration of betamethasone given for fetal lung maturity and perinatal outcome has not been investigated. This may be due to an absence of a reliable method for measuring serum betamethasone concentrations. We aimed in the current study to assess the feasibility of a specific ELISA kit to measure the concentrations of betamethasone in maternal serum and to examine the trend of sequential measurements after a course of betamethasone for fetal lung maturity.
  
  
  METHODS
  Pregnant women at risk for preterm birth who received betamethasone between 24 and 34 weeks of gestation were prospectively included. Serum concentrations were determined before administering betamethasone (baseline), and 36 hours, 48 hours, 72 hours, and 5 to 7 days after the 1(st) dose. Betamethasone concentration in samples was determined using Corticosteroid ELISA kit. The Friedman test was used to test whether there were significant differences between the measurements.
  
  
  RESULTS
  Five singleton pregnancies were included. Using the ELISA kit, betamethasone concentration in maternal serum samples was obtained for all women. Among the five measurements performed, the concentration was highest at 36 hours after the 1(st) dose and close to baseline at the 5(th) measurement performed after 5 to 7 days (p < 0.05). Serum concentration varied at each time point between the five women but similar trend was observed.
  
  
  CONCLUSIONS
  Betamethasone concentration is measurable in the serum of pregnant women with this ELISA kit.
authors: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, 18101, Israel. salim_ra@clalit.org.il.|Rappaport Faculty of Medicine, Technion, Haifa, Israel. salim_ra@clalit.org.il.
authors: Raed
authors: R
authors: Salim
authors: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, 18101, Israel. abeer_su@clalit.org.il.
authors: Abeer
authors: A
authors: Suleiman
authors: Clinical Microbiology Laboratory, Emek Medical Center, Afula, Israel. colodner_ra@clalit.org.il.
authors: Raul
authors: R
authors: Colodner
authors: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, 18101, Israel. nachum_zo@clalit.org.il.|Rappaport Faculty of Medicine, Technion, Haifa, Israel. nachum_zo@clalit.org.il.
authors: Zohar
authors: Z
authors: Nachum
authors: Rappaport Faculty of Medicine, Technion, Haifa, Israel. goldstein_le@clalit.org.il.|Department of Internal Medicine C, Clinical Pharmacology and toxicology Unit, Emek Medical Center, Afula, Israel. goldstein_le@clalit.org.il.
authors: Lee H
authors: LH
authors: Goldstein
authors: Department of Obstetrics and Gynecology, Emek Medical Center, Afula, 18101, Israel. shaleve@technion.ac.il.|Rappaport Faculty of Medicine, Technion, Haifa, Israel. shaleve@technion.ac.il.
authors: Eliezer
authors: E
authors: Shalev
mesh_terms: D000328:Adult; D001623:Betamethasone / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D047928:Premature Birth / Q000188:drug therapy; D011446:Prospective Studies; D012127:Respiratory Distress Syndrome, Newborn / Q000517:prevention & control
chemical_list: D001623:Betamethasone