Lung development in diamniotic twins discordant for complete urinary tractobstruction

Objectives: To investigate the effect of anhydramnios on the lung developme nt of 1. twin in the presence of a normal amniotic fluid volume in its diam niotic co-twin, Methods: Three sets of diamniotic twins, discordant for com plete urinary tract obstruction and anhydramnios, were followed prospective ly with regular ultrasound scans and after delivery, Results: All 3 twins w ith complete urinary tract obstruction and anhydramnios died within 2 days after birth, with confirmed severe pulmonary hypoplasia. In every case the twin with a normal amount of surrounding amniotic fluid had a normal postna tal outcome, Conclusions: The observation that a normal amniotic fluid volu me in one sac does not protect the anhydramniotic twin from pulmonary hypop lasia has important implications for the aetiology of the condition and for the possibility of therapeutic septostomy. These results are discussed in relation to previous human and animal studies.