J. Perinat. Med. 32 (2004) 220–224 • Copyright  by Walter de Gruyter • Berlin • New York Oral nifedipine maintenance therapy after acute intravenous tocolysis in preterm labor N. Cenk Sayin 1, *, Fu ¨ sun G. Varol 1 , Petek Balkanli-Kaplan 1 and Mu ¨ ge Sayin 2 1 Trakya University, Faculty of Medicine, Department of Obstetrics and Gynecology, Edirne, Turkey 2 State Hospital of Edirne, Edirne, Turkey Abstract Aims: Our aim was to evaluate the efficacy of mainte- nance oral nifedipine in pregnant women initially treated with intravenous ritodrine plus verapamil for preterm labor. Methods: The study included 73 patients with preterm labor with intact membranes. Patients were randomized to receive either maintenance oral nifedipine therapy (ns37) administered 20 mg every six hours or no treat- ment (controls, ns36) after discontinuation of acute intravenous tocolysis. Results: Compared to the control group, the mean"SD time gained from initiation of maintenance therapy to delivery (26.65"18.89 vs. 16.14"12.91 days, ps0.007) and the gestational age at delivery (37.03"2.06 vs. 35.1"3 weeks, ps0.003) were higher in the nifedipine maintenance therapy group. The proportion of patients who required one or more courses of subsequent intra- venous therapy and perinatal outcomes were similar in the maintenance therapy and control groups. Conclusions: The gestational age and time gained from initiation of maintenance therapy to delivery were longer in women receiving oral maintenance tocolysis with nife- dipine. However, maintenance therapy did not decrease the recurrence of preterm labor episodes or improve per- inatal outcomes. Keywords: Maintenance therapy; nifedipine; preterm. Introduction Prematurity is the leading cause of perinatal morbidity and mortality. Interventions, such as intensive observa- tion, home uterine activity monitoring, bed rest or toco- *Corresponding author: Dr. N. Cenk Sayin Trakya Universitesi, Tıp Faku ¨ ltesi Kadın Hastalıkları ve Dogum A.D 22030, Edirne/Turkey Tel: q90 284 235 55 42 E-mail: ncsayin@yahoo.com lytic use, have not reduced preterm births w8x. Different agents and routes of therapy have been tried for the management of preterm labor. Since the risk of recurrent preterm contractions that require hospitalization, preterm births and neonatal complications related to prematurity still exist in spite of acute tocolytic therapy, maintenance therapy may be an alternative choice to prevent these complications. Although oral b-agonists, magnesium, nifedipine, diltiazem or subcutaneous terbutaline have been used for maintenance therapy w5, 9, 11, 14x, authors found no significant prolongation of pregnancy or improvement in perinatal outcome. In a meta-analysis, it was observed that maintenance tocolytic therapy after successful treatment of an acute episode of preterm labor neither reduced the incidence of recurrent preterm labor and preterm delivery nor improved perinatal out- come. However, in this meta-analysis magnesium sulfate was the drug of choice for acute tocolysis in eight out of 12 studies (the others were ritodrine, indomethacin, ethanol and atosiban), while for maintenance therapy oral terbutaline, sulindac, ritodrine and subcutaneous atosi- ban were also employed w15x. In a Medline search, we found only one study that compared oral nifedipine with no treatment for mainte- nance therapy after acute successful parenteral tocolys- is. Carr et al. w3x administered maintenance therapy with oral nifedipine after intravenous (iv) magnesium sulfate tocolysis, but did not observe any positive effect on ges- tational prolongation. Our study was therefore designed to determine the efficacy of maintenance oral nifedipine therapy in prolonging gestation and improving perinatal outcomes after successful acute iv tocolytic therapy with ritodrine plus verapamil. Methods The study included 73 pregnant women aged between 16 and 42 who were admitted to our department with a diagnosis of preterm labor. Gestational age was based on the last menstrual period, according to a reliable menstrual history. An ultrasound examination was performed to confirm gestational age and fetal well-being. The study was approved by the Institutional Review Board and all patients gave informed consent before enrollment. As in other studies, preterm labor was diagnosed by regular uterine contractions of over four per hour with documented cer- vical change on serial digital examinations w9, 14x. All patients had intact fetal membranes and had no medical or obstetric condition requiring delivery. Exclusion criteria were cervical dila- tion G4 cm, triple or higher order pregnancy, documented intra-