A retrospective cohort study of factors relating to the longitudinal change in birth weight
نویسندگان
چکیده
BACKGROUND Recent reports have shown a decrease in birth weight, a change from prior steady increases. Therefore we sought to describe the demographic and anthropometric changes in singleton term fetal growth. METHODS This was a retrospective cohort analysis of term singleton deliveries (37-42 weeks) from January 1, 1995 to January 1, 2010 at a single tertiary obstetric unit. We included all 43,217 neonates from term, singleton, non-anomalous pregnancies. Data were grouped into five 3-year intervals. Mean and median birth weight (BW), birth length (BL), and Ponderal Index (PI) were estimated by year, race and gestational age. Our primary outcome was change in BW over time. The secondary outcomes were changes in BL and PI over time. RESULTS Mean and median BW decreased by 72 and 70 g respectively (p < 0.0001) over the 15 year period while BL also significantly decreased by 1.0 cm (P < 0.001). This contributed to an increase in the neonatal PI by 0.11 kg/m(3) (P < 0.001). Mean gestational age at delivery decreased while maternal BMI at delivery, hypertension, diabetes, and African American race increased. Adjusting for gestational age, race, infant sex, maternal BMI, smoking, diabetes, hypertension, and parity, year of birth contributed 0.1 % to the variance (-1.7 g/year; 26 g) of BW, 1.8% (-0.06 cm/year; 0.9 cm) of BL, and 0.7% (+0.008 kg/m(3)/year; 0.12 kg/m(3)) of PI. These findings were independent of the proportional change in race or gestational age. CONCLUSIONS We observed a crude decrease in mean BW of 72 g and BL of 1 cm over 15 years. Furthermore, once controlling for gestational age, race, infant sex, maternal BMI, smoking, diabetes, hypertension, and parity, we identified that increasing year of birth was associated with a decrease in BW of 1.7 g/year. The significant increase in PI, despite the decrease in BW emphasizes the limitation of using birth weight alone to define changes in fetal growth.
منابع مشابه
Retrospective cohort study of factors relating to the longitudinal change in 1 birth weight
متن کامل
Survival of Premature and Low Birth Weight Infants: A Multicenter, Prospective, Cohort Study in Iran
ABSTRACTBackground: The survival rate of preterm and low-birth-weight (LBW) infants depends on various factors such as birth weight, gestational age, and quality of care. The present study aimed at evaluating the survival rate of preterm and LBW infants, predictive factors, and the risk of mortality in three training hospitals of Mashhad and Tabriz cities.Methods: This prospective, cohort study...
متن کاملThe Effect of Ramadan Fasting On Neonatal Weight In Different Trimesters Of Pregnancy
Background and Objectives: several investigations have been done to evaluate the effect of Ramadan fasting on fetal and maternal health, which have all led to controversial results. The role of Ramadan fasting time in birth weight is still unclear. This study evaluated the effect of fasting at different periods of pregnancy on birth weight. Methods: 250 pregnant women fasting at least one day d...
متن کاملRelationship between Ureaplasma urealyticum Colonization and Bronchopulmonary Dysplasia in Very Low Birth Weight Premature Infants: A Prospective Cohort Study
Background: Bronchopulmonary dysplasia (BPD) is the second prevalent lung disease and one of the care challenges of premature newborns. Different risk factors play an important role in the development of this disease. Therefore, the aim of the present study was to investigate the relationship between colonization with Ureaplasma urealyticum and BPD.Methods: This prospective cohort study w...
متن کاملFirst Primary Tooth Eruption and its Relationship with Birth Weight
Background and purpose: In this study we aimed to identify the association between birth weight and first primary tooth eruption. Materials and methods: This retrospective cohort study was done in infants attending for 12 and 18 months vaccination in Qaemshahr health centers. Multi-stage cluster sampling was performed. Information, including birth weight, height, and head circumference were ex...
متن کاملInvestigating Risk Factors for Low-Birth-Weight Infants Born to Mothers Referring to Community Health Centers in the City of Yazd
Introduction: One of the most valuable indicators determining the health status of a community is the birth weight of infants. Thus, the purpose of this study was to investigate risk factors affecting low-birth-weight infants born to mothers visiting community health centers in the city of Yazd in Iran. Methods: The present study was a retrospective cohort research on 280 mothers visiting to c...
متن کامل