Intravenous ritodrine therapy: a comparison between twin and singleton gestations.

The purpose of this study was to determine whether or not guidelines for intravenous ritodrine therapy for singleton pregnancies in premature labor also apply for twin gestations. Between January 1982 and March 1985, 43 (18%) of 239 women admitted in premature labor had twin fetuses. Intravenous ritodrine therapy was used for four or more hours in 23 of these pregnancies. Compared with a matched group of 23 singleton pregnancies, increases in maternal and fetal heart rates and decreases in maternal diastolic blood pressures were not significantly different. Undesired cardiovascular effects were no more common and usually occurred during the initial infusion period when the dose was increased most rapidly. The averaged doses, duration of therapy, and delays in delivery were also similar between the twin and singleton groups.