RENO, NEV. — While many physicians commonly use oral tocolysis maintenance after intravenous tocolysis in patients with preterm labor because they have a clinical impression of its effectiveness, solid evidence for this practice has been lacking until recently, according to Perkin Stang, M.D., of Wayne State University, Detroit, and colleagues.
Their population-based historical cohort study suggests that pregnant patients who are not maintained on oral tocolysis are more than twice as likely to deliver prematurely as are those who do receive oral maintenance, the investigators reported in a poster presentation at the annual meeting of the Society for Maternal-Fetal Medicine.
The study involved 170,258 patients from a perinatal database in the state of Schleswig-Holstein, Germany.
Of those patients, 9,542 with preterm labor who received intravenous tocolysis were included in the study. Women with premature rupture of membranes and medically indicated inductions before 37 weeks of gestation were excluded from the analysis.
Investigators compared 4,936 women who received oral maintenance tocolysis with a β-sympathomimetic agent to 4,536 women who did not receive oral tocolysis. (Data were unavailable for the remaining 70 patients.)
In the oral tocolysis group, 366 patients (7%) delivered prematurely versus 1,094 patients (24%) in the control group.
After adjusting the results for possible confounding variables such as prior preterm delivery, cerclage, incompetent cervix, duration of intravenous tocolysis, and obesity, investigators calculated an odds ratio of 2.4 for preterm delivery in patients who were not maintained on oral tocolysis.