Short cervix: a cause of preterm delivery in young adolescents?

To test the hypothesis that at midgestation younger adolescents (<16 years of age at conception) have shorter cervices than older adolescents (16-19 years of age at conception).

At midgestation (22.9 +/- 2.4 weeks) we measured cervical length by transvaginal ultrasound in a group of 46 13-19-year-old participants in an intensive, adolescent-oriented, antenatal program. Subjects were also comprehensively screened and treated for other recognized physiologic, microbiologic, obstetric, behavioral, and psychosocial factors associated with preterm delivery. Univariate, bivariate, and logistic regression analyses were used.

The 18 younger adolescents had significantly shorter cervices than the 28 older adolescents (30 +/- 11 mm vs. 39 +/- 8 mm; P = 0.002). The younger adolescents' cervices were also more likely to be < or =25 mm long (33% and 4%, respectively; P = 0.02) and to exhibit funneling (39% vs. 4%; P = 0.01). Teenagers with cervices < or =25 mm long were younger, thinner, more apt to report vaginal bleeding and substance abuse, and to be treated for preterm labor (71% vs. 21%; P = 0.005). Logistic regression analyses revealed that age <16 years at conception (odds ratio = 13.7; 95% CI: 1.3-151.4) and substance abuse (odds ratio = 8.5; 95% CI: 1.2-62.8) were associated with cervical length < or =25 mm. Cervical length < or =25 mm was the only significant predictor of preterm delivery (odds ratio = 26.2; 95% CI: 2.1-333.6; P = 0.01) in this population of adolescents who were routinely treated for other recognized causes of preterm delivery.

Cervical length < or =25 mm and cervical funneling may be complications of conception prior to 16 years of age. Randomized trials are needed to determine if younger adolescents benefit preferentially from ultrasound screening for short cervix at midgestation.