Young maternal age and parity. Influences on pregnancy outcome

Abstract

The influence of very young maternal age and parity on pregnancy outcome was examined in a cohort of nearly 900 adolescents and mature women from Camden, New Jersey. Young primigravid primiparas (aged 12 to 15 years) were compared with mature primigravid primiparas (18 to 29 years). Young multiparas (19 years or younger, with a first pregnancy at the age of 12 to 15 years) were compared with mature, multiparas (19 to 29 years old, with a first pregnancy at 18 years or older). After controlling for confounding factors, young primiparas were found to have a modest increase in preterm delivery, which was not statistically significant. However, low gynecologic age contributed disproportionately to the risk of preterm delivery in this group, with risk decreasing with each year from menarche (Cox's proportional hazard, 0.80; 95% confidence interval [CI], 0.68 to 0.94). Among multiparas, there were several statistical interactions associated with increased risk of small-for-gestational-age infants, including interactions between young age and low pre-pregnancy body mass (adjusted odds ratio [AOR], 5.74; 95% CI, 2.18 to 15.08), young age and a prior low-birth-weight infant (AOR, 10.58; 95% CI, 3.89 to 28.77), and young age and a prior preterm delivery (AOR, 5.52; 95% CI, 2.04 to 14.98). Thus, while chronologic age per se may not be a good predictor of pregnancy outcome, adolescents remain a high-risk group because of factors that are more common among them (e.g., biologic immaturity, inadequate prenatal care, poverty, minority status, low prepregnancy weight) and because factors associated with an early adolescent pregnancy, such as low gynecologic age, may continue to influence the outcome of subsequent pregnancies.

PIP: The authors explored the influence of young maternal age and parity upon pregnancy outcome in a cohort of almost 887 adolescents and mature women from Camden, New Jersey. Primigravid primiparas aged 12-15 years were compared with mature primigravid primiparas aged 18-29 years. Multiparas aged 19 years and younger were compared with multiparas aged 19-29. The young multiparas had their first pregnancy at age 12-15 years, while the older multiparas had their first pregnancy at age 18 years or older. After controlling for confounding factors, the younger primiparas were found to have a modest, statistically insignificant increase in preterm delivery. Low gynecologic age, however, contributed disproportionately to the risk of preterm delivery in the group, with risk decreasing with each year from menarche. Statistical interactions associated with increased risk among multiparas of small-for-gestational-age infants included interactions between young age and low pre-pregnancy body mass, young age and a prior low-birth-weight infant, and young age and a prior preterm delivery. Although chronologic age may not be a good predictor of pregnancy outcome, adolescents remain a high-risk group due to factors which are more common among them such as biologic immaturity, inadequate prenatal care, poverty, minority status, and low prepregnancy weight, and because factors associated with an early adolescent pregnancy, such as low gynecologic age, may continue to influence the outcome of subsequent pregnancies.