Young maternal age and preterm labor

PURPOSE: The relationship among young age, biologic immaturity (as indexed by low gynecologic age), and the causes of preterm delivery (idiopathic preterm labor [PTL], premature rupture of the membranes [FROM], and medical indications) were investigated among 605 primigravidas from the Camden Study. METHODS: The sample consisted of 366 young adolescents < 16 years at the time of their last menstrual period (LMP) and 239 older women, 18-29 years at LMP (controls). The young adolescents were significantly shorter, thinner, had younger ages at menarche, and over a third (36.3%) were of low gynecologic age, i.e., their chronologic age was 2 or fewer years more than their age at menarche. RESULTS: Adjusting for ethnicity, cigarettes smoked/day, weight gain rate, height, fetal sex, gestational diabetes mellitus, and pregnancy-induced hypertension, young adolescents overall had a nearly 75% increased risk of PTL (adjusted odds ratio [AOR] = 1.74, 95% confidence interval [95% CI]: 1.07-2.84), and preterm delivery with PTL (AOR = 2.08, 95% CI: 1.08-4.00). There was a modest decreased risk of preterm delivery among young gravidas attributable to other causes, such as FROM or medical indications (AOR = 0.70, 95% CI: 0.28-1.75). This increased risk of PTL and preterm delivery with PTL was principally attributable to biologic immaturity. Young age with low gynecologic age was associated with a twofold risk of PTL (AOR = 2.15, 95% CI: 1.19-3.89) and preterm delivery with PT,(AOR = 2.64, 95% CI: 1.23-5.65), while the risk associated with young age and higher gynecologic age was only increased moderately. CONCLUSIONS: Young adolescents, and especially those of low gynecologic age, appear prone to TTL and are at increased risk for preterm delivery through this pathway. (C) 1997 Elsevier Science Inc.