PROTON MAGNETIC-RESONANCE SPECTROSCOPY OF HUMAN AMNIOTIC FLUIDS SAMPLED AT 17-18 WEEKS OF PREGNANCY IN CASES OF DECREASED DIGESTIVE ENZYME-ACTIVITIES AND DETECTED CYSTIC-FIBROSIS

Low digestive enzyme activities in human amniotic fluid can be observe d in normal and disease-affected pregnancies: cystic fibrosis, trisomy 21, intestinal atresia. Amniotic fluids were analyzed by proton nucle ar magnetic resonance (NMR) spectroscopy in order to specify prenatall y the etiology of low digestive enzyme activities observed at 17-18 we eks of amenorrhea. A total of 114 amniotic fluid-samples were collecte d at 17-18 weeks of amenorrhea. Karyotyping and assays of digestive en zyme activities were performed in all cases. Samples were divided into six groups according to enzyme activities and pathology. Proton spect ra were retrospectively recorded. Many compounds, such as amino acids and carboxylic acids, were detected by NMR. The same resonance intensi ties (normalized to creatinine) were observed in the six groups. Never theless, an unidentified resonance at 1.05 ppm was detected in seven o ut of 13 cases of cystic fibrosis affected fetuses. The NMR spectra de monstrated the stability of the amniotic fluid composition at 17-18 we eks of amenorrhea, even when the fetus was affected by a disease such as trisomy 21 or intestinal atresia. The resonance associated with mos t cases of cystic fibrosis should be further investigated.