B-type natriuretic peptide levels are correlated with birth-weight discordance in monochorionic-diamniotic twins without twin–twin transfusion syndrome

Objective:to determine whether b-type natriuretic peptide (bnp) levels in umbilical cord blood (ucb) and amniotic fluid (af) are correlated with birth-weight discordances in monochorionic-diamniotic twins.study design:the ucb–bnp and af–bnp levels were determined at birth in 36 twin-pairs without twin–twin transfusion syndrome (ttts).result:both the ucb–bnp and the af–bnp levels were significantly higher among twins with either a birth-weight discordance ⩾20% (141.6 versus 52.9 pg ml−1 for ucb–bnp, 38.0 versus 17.2 pg ml−1 for af–bnp) or cardiac dysfunction at birth (167.2 versus 56.3 pg ml−1 for ucb–bnp, 34.9 versus 19.0 pg ml−1 for af–bnp), compared with neonates without the respective characteristics. the ucb–bnp and af–bnp levels in both the larger and the smaller twins were significantly correlated with birth-weight discordance.conclusion:cardiac dysfunction occurs in both larger and smaller co-twins with increasing birth-weight discordances, even in the absence of ttts.