Background : Infant mortality rate is one of the most important health index in societies for which low birth weight plays the most important role. The present study was carried out in Qom province to determine this index and its related factors.

Materials and methods : For this cross sectional study 1927 newborns were selected from different private and public delivery units. A questionnaire was completed and infant’s mothers were interviewed and pediatricians examined Infants. Finally, those LBW newborns were entered for analysis.

Results : Of 1927 newborns, 11.8% weighed under 2500 grams, of these 47% had mothers aged less than 18 years and 10% had mothers aged more than 35 years. 51% of these infants were female. There was a significant correlation between previous history of abortion and LBW infant delivery, however, we could not find any association between maternal occupation and level of education with LBW infants.

Conclusion : The high prevalence of LBW infants in Qom province is noticeable. Further studies are strongly recommended.

Background: Accurate estimated fetal weight (EFW) has importance in the management of labor and delivery. Estimated fetal weight was done in two sonographic and clinical ways (Palpation of abdomen). Many studies have been conducted for comparing clinical and sonographic EFW. With regard to contraindications and absence of studies in this area, this research was conducted on women admitted due to termination of pregnancy in Shabih Khani Maternity Hospital in 1383

Materials and Methods: This research as a cross-sectional study was done on 100 women with gestational 37/42-week ages admitted for termination of pregnancy. Excluded criteria consists of premature rupture of membrane, placenta abruption- placenta previa , preeclampsia, fetal abnormality , amniotic fluid disorder Clinical estimation in labor was performed by senior resident or obstetrician and sonographic estimation was performed by sonographists. The actual birth weight was determined by electronic scales and recorded in the chart immediately after delivery. Accuracy of birth weight estimation was determined by calculating the percentage error, and the proportion of estimates within 10% of the actual birth weight. Then processing of information performed by chi-square, fisher exact test and relative risk was determined

Results : study on 100 pregnant woman showed mean age was 22.5 ± 4.5 and mean gestational age was . 39.2 ± 0.9 and mean birth weight was 3513 ± 370.3 .Birth weight in %10 of new born was less than 3000 gr and %12 of birth weight was more than 4000 gr . In total pregnant women clinical estimation in (83 women) 83% and sonographic estimation in (67 women) 67% was acceptable in which statically were important (P= 0.009).In birth weight less than 3000 gr sonographic estimate better than clinical estimate p<0, 03

Conclusion: regarding that most of fetus is reneged between 3000-4000 gr. accuracy of clinical estimation is often more than sonographic estimation so that we can perform EFW by simple weight and without cost. But in cases such as low birth weight that sonographic estimation of weight as direct diagnosis are defined and in obese women due to difficulty of clinical estimation , we suggest sonographic estimation to use.