Impact of maternal anaemia on birth outcomes of teen twin pregnancies: a comparative analysis with mature young mothers.

We investigated the impact of maternal anaemia on birth outcomes among adolescent twin pregnancies in the United States using the vital statistics records for matched multiple births covering the years 1995-1997 inclusive. The study group consisted of mothers aged 19 years or younger who had a twin pregnancy. A cohort of women aged 20-29 years with twin pregnancies served as the comparison group. The main birth outcomes of interest were: low and very low birth weight, preterm and very preterm delivery, small-for-gestational age, stillbirth, neonatal and perinatal mortality. Crude and adjusted odds ratios for the above outcomes were calculated using the generalised estimating equation framework (GEE) that captured both intra- and intercluster sources of heterogeneity. Although not statistically significant, we detected an elevated risk for stillbirth among anaemic women (20-30%) in either age cohort, a magnitude that is substantial at the population level as well as warranting further aetiological investigations.