title: The combined effect of betamethasone and ritodrine on the middle cerebral artery in low risk third trimester pregnancies.
abstract: OBJECTIVE
  To evaluate the effect of antenatal betamethasone and ritodrine in third trimester low risk singleton pregnancies by Doppler technology.
  
  
  METHODS
  Eighty-four third trimester pregnant women who received a full course of betamethasone and delivering uneventfully were recruited. The Doppler examination included the assessment of the pulsatility index (PI) of the umbilical artery (UA PI) and the middle cerebral artery (MCA PI) prior to treatment (baseline), and 48, 72 and 96 h after the second dose of betamethasone.
  
  
  RESULTS
  No significant difference was found in UA PI and UA/MCA values following betamethasone therapy. In contrast, MCA PI decreased significantly 48 h from the last injection of betamethasone in the whole study group (P<0.001), and returned to basal values at 96 h. We also found that MCA PI was reduced significantly at 48 h in the subgroup under tocolysis (n=41) and in the subgroup not receiving tocolysis (n=43). We compared MCA PI values for both subgroups in the four timings, and found a non-significant difference comparing baseline and 96 h values. However, when comparing MCA PI values after 48 and 72 h, significantly lower differences in PI values in both subgroups were found.
  
  
  CONCLUSIONS
  In low risk pregnancies, betamethasone therapy in the third trimester is related to a significant but transient reduction of MCA PI, which is more pronounced during tocolytic therapy. Although the physiological basis of this effect is currently unclear, it could be related to the local regulation of intracerebral blood flow.
authors.affiliation: Institute of Gynecology, Perinatology and Child Health, University La Sapienza, Rome, Italy. jjpiazze2000@hotmail.com
authors.forename: Juan
authors.initials: J
authors.lastname: Piazze
authors.forename: Maurizio M
authors.initials: MM
authors.lastname: Anceschi
authors.forename: Albana
authors.initials: A
authors.lastname: Cerekja
authors.forename: Erich
authors.initials: E
authors.lastname: Cosmi
authors.forename: Paolo
authors.initials: P
authors.lastname: Meloni
authors.forename: Alessandro
authors.initials: A
authors.lastname: Alberini
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pizzulo
authors.forename: Tamara
authors.initials: T
authors.lastname: Argento
authors.forename: Ermelando V
authors.initials: EV
authors.lastname: Cosmi
mesh_terms: D001623:Betamethasone / Q000494:pharmacology*; D005260:Female; D005333:Fetus / Q000098:blood supply*; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008431:Maternal-Fetal Exchange; D020768:Middle Cerebral Artery / Q000187:drug effects*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012312:Ritodrine / Q000494:pharmacology*; D015149:Tocolytic Agents / Q000494:pharmacology*
chemical_list: D005938:Glucocorticoids; D015149:Tocolytic Agents; D001623:Betamethasone; D012312:Ritodrine