Effect of Young Maternal Age and Skeletal Growth on Placental Growth and Development

Objectives: Teenagers are susceptible to delivering small-for-gestational-age infants. Previous studies implicate continued skeletal growth as a contributory factor, and impaired placental development was the primary cause of fetal growth restriction in growing adolescent sheep. The aims of this study were to examine the impact of young maternal age and growth on placental development.

Study Design: Placentas were collected from 31 teenagers, of which 12 were growing and 17 non-growing based on knee height measurements. An adult control group (n = 12) was included.

Main Outcome Measures: Placental weight and morphometric measurements of villous, syncytiotrophoblast, fibrin and vessel areas, as well as indices of proliferation and apoptosis, were analysed in relation to maternal growth and age.

Results: Growing teenagers had a higher birthweight:placental weight ratio than non-growing teenagers (p < 0.05). Villous area, syncytial area, fibrin content, vascularisation and cell turnover did not differ between growing and non-growing teenagers. There were no differences in placental weight or morphometry between adult and teenage pregnancies. Maternal smoking, a potential confounding factor, did not exert a major influence on the placental parameters examined, except for a stimulatory effect on placental proliferation (p < 0.05) and syncytial knot formation (p < 0.05).

Conclusions: We were unable to detect any major differences in placental size or composition between growing and non-growing teenagers. Birthweight:placental weight ratio was higher in growing compared to non-growing teenagers. This suggests that maternal growth may affect placental function rather than development, and is consistent with our recent observations that maternal growth was not detrimental to fetal growth.