Iranian Red Crescent Medical Journal Maternal Risk Factors and Neonatal Outcome of the Admitted Patients for Preterm Spontaneous Uterine Contractions B Namavar Jahromi*1, L Salarian 1 , Z Shiravani1 1Department of Obstetrics and Gynecology, Perinatology Research Center, Shiraz University of Medi- cal Sciences, Shiraz, Iran ORIGINAL ARTICLE Abstract Background: Preterm birth (PTB) is one of the most important unsolved problems in reproductive medicine. This study aims to evaluate several maternal risk factors and outcome of pregnancies who were admitted for preterm spontaneous uterine contractions (PSUC). Methods: From September 2007 to February 2009, 327 cases who were admitted for PSUC were retrospective- ly studied. They were classified according to their fetal numbers and presence of true versus threatened preterm labor (PTL). Results: There were 297 (90.82%) singleton, 27 (8.25%) twin and 3 (0.91%) triplet pregnancies. Only 12 women (3.6%) fulfilled the ACOG criteria for PTL who delivered in a few hours and 315 cases (96.3%) were classified as threatened PTL and most of them were discharged undelivered from the hospital. 103 cases were missed and 224 mothers and their 247 neonates remained. 121 women from this cohort had PTB and delivered before 259 days (54%). Pregnancy outcomes including; the time interval between admission for PSUC and delivery, the mean gesta- tional ages at birth, birth weights, number and duration of NICU admissions were evaluated in each group. Conclusion: Regular uterine contractions even in the absence of cervical changes should be considered as a potential risk factor for PTB. The most frequently associated maternal risk factors were history of abortion, infertil- ity and previous PTB, and the most frequently associated complications were preterm rupture of membranes, vaginal bleeding and febrile diseases. Keywords: Preterm birth; Preterm uterine contraction; Preterm labor; Risk factor; Abortion; Infertility Introduction Preterm birth (PTB) is one of the most important unsolved problems in reproductive medicine. PTB is defined as delivery that occurs at more than 20 and less than 37 gestational weeks. PTB is the leading cause of perinatal morbidity and neonatal mortality.1,2 The incidence of PTB in most developed countries has remained constant in over the past 3 decades at about 5-10%.3 However; data demonstrates a steady *Correspondence: Bahia Namavar Jahromi, MD, Associate Profes- sor of Department of Obstetrics and Gynecology, Shiraz University of Medical Sciences, Shiraz, Iran. Tel: +98-711-6272494, Fax: +98- 711-6272492, e- mail: namavarb@sums.ac.ir Received: June 12, 2011 Accepted: September 10, 2011 rise in the preterm birth rate in certain populations over the past 20 years.1 Spontaneous PTB occurs when the parturitional process begins in the absence of overt maternal or fetal illness.2 Decreased local progestrone concentrations, oxytocin initiation, decidual activation4 and deviation from normal fetal growth5 had been implicated as pathogenesis of PTB. On the other hand, preterm labor (PTL) which is the onset of regular uterine contractions accompanying with cervical change, after the 20th week of gestation and before 37 completed weeks or 259 days of pregnancy1,2 proceeds PTB. However, outcome of threatened PTL which is diagnosed when there are documented uterine contractions without evidence of cervical changes3 is not yet accurately documented. Iran Red Crescent Med J 2011; 13(12):877-883 ©Iranian Red Crescent Medical Journal