Risk factors in preterm contractions Table 1: Simultaneous maternal diseases in the women with Preterm spontaneous uterine contractions at the ad- mission time Maternal diseases P valuea Singleton no. (%) Twin no. (%) Triplet no. (%) n=297 n=27 n=3 History of at least one 65 (21.8) 9 (33) 1 (33) 0.297 previous abortion Infertility 49 (16.49) 10 (37) 2 (66.6) 0.227 Primary infertility 33 (11.1) 7 (25.9) 2 (66.6) 0.004 Secondary infertility 16 (5.38) 3 (11.1) 0 0.006 History of Previous PTB 26 (8.75) 1 (3.7) 1 (33) 0.001 Uterine diseases 25 (8.41) 2 (7.4) 0 0.001 Cervical incompetence 13 (4.37) 2 (7.4) 0 0.001 Myoma in uterus 8 (2.69) 0 0 - Bicornate uterus 3 (1.01) 0 0 - Septated uterus 1 (0.33) 0 0 - Cardiac diseases 19 (6.39) 1 (3.7) 0 0.001 Mitral valve Prolapse 16 (5.38) 0 0 - Aortic stenosis 1 (0.33) 0 0 - Subaortic web 1 (0.33) 0 0 - Pulmonary HTN 1 (0.33) 1 (3.7) 0 0.001 Symptomatic renal stone 17 (5.72) 0 0 - Thyroid disease 16 (5.38) 3 (11.10 0 0.001 Hypothyroidism 10 (3.36) 1 (3.7) 0 0.001 Hyperthyroidism 3 (1.01) 2 (7.4) 0 0.001 Chronic HTN 9 (3.03) 0 0 - Asthma 4 (1.34) 0 0 - Antiphospholipid antibody syndrome 4 (1.34) 2 (7.4) 0 0.001 Overt Diabetes 2 (0.67) 0 0 - aP value was computed if the sample size was sufficient for Fisher's exact test to evaluate the association between presence of the certain conditions and number of fetuses. Table 2: Pregnancy complications of the women with preterm spontaneous uterine contractions Complications Singleton no. (%) Twin no. (%) Triplet no. (%) n=297 n=27 n=3 Preterm ROM 52 (17.5) 12 (44.4) 2 (66.6) Vaginal bleeding 31 (10.43) 4 (14.8) 0 Abruption 4 (1.34) 1 (3.7) 0 Placenta Previa 3 (1) 1 (3.7) 0 Pyelonephritis 27 (9.1) 1 (3.7) 0 Pneumonia 3 (1) 1 (3.7) 0 Hypertensive disorders 20 (6.73) 2 (7.4) 0 Gestational Diabetes 20 (6.73) 3 (11.1) 0 Polyhydramnious 6 (2.02) 1 (3.7) 0 Oligohydramnious 6 (2.02) 1 (3.7) 0 a The triplet group was excluded from the analysis if the complication was absent in the group. P value a 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 plet group (33.3%) had anomalies including heart disease 2 (22.2%) and bowel obstruction 1 (11.1%). Discussion In this retrospective study, we included all of 327 cases who were admitted to Hafez Hospital for sponta- neous uterine contractions from 23rd September 2007 to 28th February 2009. The characteristics of the pelvic examinations and contraction frequencies of these cases on the admission time were compared with ACOG cri- teria to confirm the diagnosis of PTL.1 Surprisingly, we found that only 12 women (3.6%) fulfilled the criteria WWW.ircmj.com Vol 13 December 2011 879