Original Investigation 182
IntroductionPreterm birth is a serious health problem associated with neonatal morbidity and mortality (1). Preterm birth is the leading cause of neonatal mortality and the second prevalent cause of mortality in children aged less than 5 years (2). Additionally, the rate of death by other causes, such as neonatal infections, in preterm neonates are higher than term neonates (3). The World Health Organization defined preterm labor as live birth before 37 weeks of gestation. Preterm birth is classified to three subgroups as defined by gestational age: extremely preterm (<28 weeks), very preterm (28-<32 weeks), and moderate preterm (32-<37 completed weeks of gestation) (4). Moderate preterm birth includes late preterm birth (34-<37 completed weeks of gestation). The occurrence of preterm birth was reported as 5-18%, worldwide. The prevalence of preterm labor in Iran has been estimated to be 10-15% of deliveries (4,5). Recent strategies to avert preterm labor are used to prevent mechanisms that increase the frequency and severity of uterine contractions (6). Although, various tocolytic drugs are commonly used in this regard, there is no consensus on which is best (7). Leptin is a peptide and a tocolytic factor hormone. It is the product of the ob gene with a 16 kda molecular weight, 167 amino acids long, and a half-life of 25 (8-10). During pregnancy, leptin is secreted from placental trophoblasts and enters from the placenta to the fetal and maternal body. Leptin can have a significant role on fetal growth and development, angiogenesis, and hematopoiesis (8,11). Leptin levels increase during pregnancy, in which the lowest level can be assessed in the first trimester, and the highest during the second trimester. A plateau is noted in the third trimester of pregnancy (8,12). Results have shown that leptin can affect physiological processes such as glucose metabolism and immune system responses (9,13,14). Dotsch et al. (15) mentioned that the mean leptin level in term neonates was 6-fold higher than preterm neonates. According to previous investigations, various factors, such as maternal body mass index (BMI), maternal age, and smoking cigarettes could influence the umbilical leptin levels (16). Additionally, there was a linear relationship between leptin Objective: We aimed to investigate the relationship between the level of maternal serum leptin and the occurrence of moderate preterm labor.
Material and Methods:This was a case control study conducted on pregnant women referred to Al-Zahra Hospital in Rasht, north of Iran in 2013. Cases included 30 moderate preterm delivering women and 30 control pregnant women with the same gestational age. The maternal serum leptin was measured for each mother at the time of entering the study.
Results:The mean serum leptin in the control group (56.66±34.18) was significantly higher than the preterm (33.65±16.70) group. There were no significant differences between the groups in terms of body mass index and age. Logistic regression revealed that age and...