X-ray pelvimetry of the pregnant adolescent. Pelvic size and the frequency of contraction.

Pelvic dimensions by x-ray of 282 pregnant adolescents and 181 adult women were compared to ascertain if the pelvis of the adolescent was smaller and contracted with greater frequency. The majority of 10 pelvic dimensions for black and white adolescents were significantly smaller or contracted with significantly greater frequency. The pattern of signifcant differences suggests that the adolescent pelvis has yet to mature fully by age 16. As a consequence of physiologic events during puberty, described by several authors, the adolescent pelvis grows at an accelerated rate and typically changes from an anthropoid to a gynecoid configuration. Caution must be taken in applying these results since pelvic size is not synonymous with obstetric outcome.