Body composition in pregnancies of adolescents and mature women and the relationship to birth anthropometry

Abstract

Objective: To investigate differences in body composition between adolescent girls and mature women during pregnancy and the relationship to newborn anthropometry. Design: A prospective study. Setting: The antenatal clinic at the University Hospital of the West Indies, Kingston, Jamaica. Subjects: Four hundred and twenty-five women were invited to join the study. Three hundred and sixty-one women (84.9%) completed the study. Interventions: Study participants were divided into two groups: adolescents and mature women, who were all less than 15 weeks pregnant and had no systemic illness at the time of entry into the study. A questionnaire was administered which retrieved information on demographics, age, marital status, menstrual history, parity, socio-economic status, medical history and smoking/drinking habits. Anthropometric measurements including weight, height, triceps, biceps, subscapular and suprailiac skinfolds, as well as blood pressure measurements and urine analysis were performed at the first antenatal visit and repeated at 15, 25 and 35 weeks gestation. Anthropometric measurements of the newborn were performed at birth. Results: There were significant differences between anthropometry and skinfold thickness at the first antenatal visit between the adolescents and the mature women where the adolescents had lower measurements compared to the mature women. In the newborn anthropometry, the only significant difference seen was in the triceps skinfold thickness and the mid-upper arm circumference where the newborn of the adolescents had significantly smaller values (P ¼ 0.04; P ¼ 0.02, respectively). The percentage fat, fat mass and lean body mass were significantly lower in the adolescent compared to the mature women (Po0.0001), both at the first antenatal visit and at 35 weeks gestation. A greater gain was seen in these measurements throughout the pregnancy in the adolescents (Po0.0001). Linear regression analyses showed that the gain in lean body mass was the most important predictor of birth anthropometry. Conclusion: Body composition differs in pregnancy between adolescents and mature woman, and if adequate weight and lean body mass are attained, it impacts positively on birth size irrespective of age.

Challenges in Determining Body Fat in Pregnant Women

“…This lack has resulted in the frequent use of non-pregnancy-specific methods [22,23,24,25], which can reduce the validity of the results. …”

Comparing the glucose kinetics of adolescent girls and adult women during pregnancy

“…Whereas it is known that overnight-fasted, nonpregnant adolescent girls produce glucose at approximately the same rate as adults (11), it is not known whether adolescents can increase glucose production to the same extent as their adult counterparts during pregnancy. We (12) as well as others (13) have reported that pregnant adolescents gain more weight than do their adult counterparts during pregnancy. We also showed that most of this weight gain was in lean body mass (12), suggesting that pregnant adolescents may require more amino acids than adult women to support the increased protein synthesis associated with their own growth plus the growth of their reproductive tissues and fetus.…”

“…We (12) as well as others (13) have reported that pregnant adolescents gain more weight than do their adult counterparts during pregnancy. We also showed that most of this weight gain was in lean body mass (12), suggesting that pregnant adolescents may require more amino acids than adult women to support the increased protein synthesis associated with their own growth plus the growth of their reproductive tissues and fetus. Hence, as pregnancy progresses, unlike their adult counterparts, pregnant adolescents may not have sufficient gluconeogenic precursors to support increased gluconeogenesis.…”

“…Because individual subjects' fluid retention may differ during pregnancy, as well as the fact that we have shown that adolescent girls lay down more lean body mass than adult women during pregnancy (12), each glucose kinetic parameter was also expressed per each subject's whole-body weight to determine the change within each group from trimester 1 to 3. This was achieved by multiplying each weight-specific kinetic parameter by the subject's body weight.…”

Weight retention within the puerperium in adolescents: a risk factor for obesity?

“…This increased weight gain was also seen in the current study, with the adolescents retaining more weight than the older women. An increase in gestational weight gain has been previously reported among adolescents and suggests that attainment of adequate weight and lean body mass in pregnancy impacts positively on birth size (29,32,33) .…”