Brain natriuretic peptide and endothelin-1 in the pathogenesis of polyhydramnios-oligohydramnios in monochorionic twins.
OBJECTIVE
We investigated the association between amniotic fluid levels of human brain natriuretic peptide, endothelin-1, and abnormal amniotic fluid volume in monochorionic twins with and without chronic twin-twin transfusion syndrome.


METHODS
Amniotic fluid and fetal blood samples were obtained in utero or at cesarean delivery from monochorionic twins with (n = 20) or without chronic twin-twin transfusion syndrome (n = 10). Concentrations of atrial natriuretic peptide, human brain natriuretic peptide, and endothelin-1 (in picograms per milliliters) were determined by radioimmunoassay.


RESULTS
The amniotic fluid concentrations of human brain natriuretic peptide (P <.001) and endothelin-1 (P <.001) in the recipient fetuses were higher than the donor twins but were similar in the twins with no twin-twin transfusion syndrome. In the donor twins, amniotic fluid concentrations of human brain natriuretic peptide (P <.001) and endothelin-1 (P <.001) were lower than the twin pairs with no twin-twin transfusion syndrome. In both chronic twin-twin transfusion syndrome fetuses (P <.01) and fetuses with no twin-twin transfusion syndrome (P <.001), the amniotic fluid concentrations of human brain natriuretic peptide were high, although the concentrations of the endothelin-1 were lower than the fetal plasma concentrations. A positive association was present between amniotic fluid levels of human brain natriuretic peptide and endothelin-1 (R (2) = 0.51, P <.001, n = 60). Amniotic fluid human brain natriuretic peptide (r = 0.67, P <.001) and endothelin-1 (r = 0.57, P <.01) levels of the recipient twins correlated with the amniotic fluid index.


CONCLUSIONS
These data suggest that amniotic fluid concentrations of human brain natriuretic peptide and endothelin-1 were highest in the twins with polyhydramnios and lowest in the twins with oligohydramnios, which suggests the importance of these hormones in the regulation of amniotic fluid volume.
Bajoria
Rekha
R
Academic Unit of Obstetrics and Gynaecology, St Mary's Hospital for Women and Children, University of Manchester, Manchester, United Kingdom. rbajoria@doctors.net.uk
Ward
Stuart
S
Chatterjee
Ratna
R
D000653:Amniotic Fluid / Q000737:chemistry; D009320:Atrial Natriuretic Factor / Q000032:analysis; D004200:Diseases in Twins; D019332:Endothelin-1 / Q000032:analysis / Q000502:physiology*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005330:Fetofetal Transfusion / Q000378:metabolism; D006801:Humans; D020097:Natriuretic Peptide, Brain / Q000032:analysis / Q000502:physiology*; D016104:Oligohydramnios / Q000209:etiology* / Q000378:metabolism; D006831:Polyhydramnios / Q000209:etiology* / Q000378:metabolism; D011247:Pregnancy; D012016:Reference Values
D019332:Endothelin-1; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor