A Comparison of Risk Factors for Preterm Labor and Term Small-for-Gestational-Age Birth

Abstract

This study estimates the effects of 23 factors on the prevalence of premature labor and fetal growth retardation across the entire birthweight spectrum. We studied risk factors for premature labor within the domain of babies of appropriate size for their gestational age (N = 9,490). We also studied risk factors for fetal growth retardation among babies born at term (N = 10,889). Preterm labor was associated independently with young maternal age, low pre-pregnant weight, low weekly weight gain, nulliparity, previous preterm birth, histories of two or more induced abortions, spontaneous abortions, or stillbirths, uterine exposure to diethylstilbestrol (DES), incompetent cervix, uterine anomaly, and pyelonephritis. Odds ratios ranged from 1.7 to 5.9. Fetal growth retardation, as estimated by small-for-gestational-age birth, was associated independently with black race, young maternal age, short maternal height, low prepregnancy weight, low weekly weight gain, and smoking, as well as nulliparity, previous preterm birth, three or more abortions, uterine anomaly, and uterine exposure to DES. Odds ratios ranged from 1.6 to 2.8. Our study shows the importance for etiologic understanding of separating diverse routes to low birthweight and considering the occurrence of adverse pregnancy outcomes along the entire birthweight spectrum. The findings reinforce the need for comprehensive control of confounding in studies of pregnancy outcome.

Birth outcomes associated with cannabis use before and during pregnancy

“…However, our data are inconsistent with findings of studies that have not found a significant association between cannabis use in pregnancy and birth outcomes (13,14,16,18). The existing discrepancy between the findings might be due to the difference in the study design and assessment of cannabis use (e.g., retrospective vs. prospective) (14) or level of adjustment for confounders (13,16). Using a large routinely collected data set, our study suggests a significant effect of in utero exposure to cannabis on the birth outcomes examined independent of sociodemographic background and use of other substances.…”

“…The findings of this study are consistent with previous research, which has suggested that smoking cannabis during pregnancy may lead to lower birth weight (6-9), increased rate of premature birth (7), and shorter birth length (11,12). However, our data are inconsistent with findings of studies that have not found a significant association between cannabis use in pregnancy and birth outcomes (13,14,16,18). The existing discrepancy between the findings might be due to the difference in the study design and assessment of cannabis use (e.g., retrospective vs. prospective) (14) or level of adjustment for confounders (13,16).…”

“…A number of studies have reported some adverse effects, including low birth weight (6)(7)(8)(9), preterm birth (7,8,10), small for gestational age (SGA) (7), and small birth length (11,12). However, other studies have disputed these findings (10,(12)(13)(14)(15)(16)(17)(18).…”

Validade do exame clínico do recém-nascido para a estimação da idade gestacional: uma comparação do escore New Ballard com a data da última menstruação e ultra-sonografia

“…Saúde Pública, Rio de Janeiro, 16(1):83-94, jan-mar, 2000 Introdução Apesar dos avanços alcançados pelos programas de investigação sobre os fatores de risco da prematuridade, a maioria dos nascimentos prematuros ainda não tem fisiopatogênese conhecida (Kramer, 1987;Kramer et al, 1988;Mavalankar et al, 1992;Fortier et al, 1995;Hedegaard et al, 1996;Lang et al, 1996). Dentre as principais dificuldades dessa linha de pesquisa, destaca-se a falta de consenso com relação aos indicadores e medidas usados para aferir alguns de seus potenciais fatores de risco e à estratégia padrão utilizada para seu diagnósti-co (Dunn, 1985;Henriksen et al, 1995).…”

Fatores de risco associados ao nascimento de recém-nascidos de muito baixo peso em uma população de baixa renda da Região Sul do Brasil

“…Alguns trabalhos mostraram um maior número de nascimentos prematuros entre as gestantes adolescentes 56,89,103,120,127,137 , enquanto outros autores concluíram que não houve um aumento do risco de prematuridade entre as mães adolescentes 49,57,72 .…”