THE CELOMIC CAVITY - AN IMPORTANT SITE OF MATERNO FETAL NUTRIENT EXCHANGE IN THE 1ST TRIMESTER OF PREGNANCY

Objective To measure levels of folate and vitamin B12 in matched sampl es of amniotic fluid and extra-embryonic coelomic fluid from 9 to 12 w eeks' gestation.Design Prospective observational study. Setting Homert on Hospital, London. Subjects Twenty-two women with ultrasonographical ly normal pregnancies before surgical termination. Methods Transvagina l ultrasound-guided needle aspiration of amniotic fluid and extra-embr yonic coelomic fluid was performed. Pure samples of amniotic fluid and extra-embyronic coelomic fluid were obtained from each pregnancy, and folate and vitamin B12 were measured using microbiological assays. Re sults Levels of folate and vitamin B12 were higher in extra-embyronic coelomic fluid than in amniotic fluid and maternal serum. Amniotic flu id folate levels were lower than in maternal serum whereas vitamin B12 levels in amniotic fluid were higher than in maternal serum. All diff erences in concentration were significant (P<0.0005; paired t-test). P ositive correlations were found between the concentrations of folate a nd vitamin B12 in each fluid. There was a linear correlation between g estational age and amniotic fluid folate levels (r = 0.648: P = 0.001) . Conclusions High concentrations of folate and vitamin B12 in coelomi c fluid suggest that the coelomic cavity plays an important role in th e materno-fetal exchange of these nutrients.