da Silva Antônio A M, Simões Vanda M F, Barbieri Marco A, Bettiol Heloisa, Lamy-Filho Fernando, Coimbra Liberata C, Alves Maria T S S B
Department of Public Health, University of Maranhão, and Department of Paediatrics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
Paediatr Perinat Epidemiol. 2003 Oct;17(4):332-9. doi: 10.1046/j.1365-3016.2003.00515.x.
The association between young maternal age and preterm birth (PTB) remains controversial. In some studies the association disappeared after controlling for socio-economic and reproductive factors, thus indicating that social disadvantage rather than biological factors may be the explanation. However, in other studies the association persisted after adjustment. The relation between young maternal age and PTB was studied in a city located in Brazil, an underdeveloped country, where the prevalence of teenage pregnancy was high, 29%. A systematic sampling of 2541 hospital births, stratified by hospital, was performed in São Luís, Northeast Brazil, from March 1997 to February 1998. The risks of PTB for infants born to two groups of young mothers (<18 and 18-19 years) were calculated with and without adjustment for confounding factors (family income, marital status, mode of delivery, parity, health insurance, and short maternal stature) in a logistic regression model, using mothers 25-29 years of age as the reference group. In the unadjusted analysis, the risk of PTB was higher for mothers < 18 years [odds ratio (OR) = 2.42, 95% confidence interval (CI) 1.64, 3.57]. Those aged 18 or 19 years were not at a higher risk of PTB (OR = 0.89, 95% CI 0.58, 1.38). After adjustment, the risk of PTB for mothers < 18 years was lower but remained significant after controlling for confounding (OR = 1.70, 95% CI 1.11, 2.60). After performing a stratified analysis according to parity, the risk of PTB among very young primiparae (<18 years) remained significant (OR = 1.77, 95% CI 1.02, 3.08), whereas the risk among non-primiparous adolescents was not significantly higher than the risk among mothers in the reference group. This suggests that the association between young maternal age and PTB may have a biological basis or an artifactual explanation (errors in gestational age estimation may be more common among very young mothers) or may be due to residual confounding.
年轻孕产妇年龄与早产（PTB）之间的关联仍存在争议。在一些研究中，在控制了社会经济和生殖因素后，这种关联消失了，这表明社会劣势而非生物学因素可能是其原因。然而，在其他研究中，调整后这种关联仍然存在。在巴西一个欠发达国家的城市中，对年轻孕产妇年龄与早产的关系进行了研究，该国青少年怀孕率很高，为29%。1997年3月至1998年2月期间，在巴西东北部的圣路易斯对2541例医院分娩进行了系统抽样，按医院分层。在逻辑回归模型中，以25至29岁的母亲为参照组，计算了两组年轻母亲（<18岁和18 - 19岁）所生孩子早产的风险，且对混杂因素（家庭收入、婚姻状况、分娩方式、产次、健康保险和母亲身材矮小）进行了调整和未调整两种情况的分析。在未调整分析中，<18岁母亲所生孩子早产的风险更高[比值比（OR）= 2.42，95%置信区间（CI）1.64，3.57]。18岁或19岁的母亲早产风险并未升高（OR = 0.89，95% CI 0.58，1.38）。调整后，<18岁母亲早产的风险降低，但在控制混杂因素后仍具有统计学意义（OR = 1.70，95% CI 1.11，2.60）。根据产次进行分层分析后，极年轻初产妇（<18岁）早产的风险仍然具有统计学意义（OR = 1.77，95% CI 1.02，3.08），而非初产青少年的风险并不显著高于参照组母亲的风险。这表明年轻孕产妇年龄与早产之间的关联可能有生物学基础或人为解释（极年轻母亲中孕周估计错误可能更常见），或者可能是由于残余混杂因素导致的。
