[Prenatal diagnosis by amniocentesis. Clinical and cytogenetic experience in 1,500 cases]. / Diagnóstico prenatal por amniocentesis. Experiencia clínica y citogenética en 1,500 casos.

ABSTRACT

BACKGROUND: Genetic amniocentesis is performed in México 25 years ago but only few works have been published. OBJECTIVE: To analyze clinical and cytogenetic findings in consecutive patients submitted to genetic amniocentesis. MATERIAL AND METHOD: An analysis was made of the clinical features, amniocentesis results and pregnancy outcome in 1500 consecutive cases of genetic amniocentesis. RESULTS: Sixty-eight fetuses with chromosomopathy (4.5%) were detected and two, with an inborn error of metabolism. The most frequent abnormalities were trisomy 21 (32 cases), trisomy 18 (10 cases), trisomy 13(6 cases), 45,X (6 cases), 47,XXY (4 cases). Pregnancy outcome is known in 474 patients (32%). There were five fetal losses (1%). Of the 68 cases with chromosomopathy, the outcome is known in 45, of which, 29 (64%) decided to have an abortion while 16 (35%) continued the pregnancy, six had a spontaneous abortion or perinatal death and ten had an alive new born. Among fetuses with normal or balanced karyotype and normal ultrasound, 11 out of 419 (2.6%) had congenital anomalies. Two of them had a condition known to be related with epigenetic regulation, (Russell Silver and Angelman syndrome). CONCLUSIONS: Amniocentesis is a reliable and low risk method. Cytogenetic findings in this series are similar to those reported in the literature. Most patients with fetal disease decided to have an abortion. The finding of two patients with a condition related with abnormal epigenetic regulation suggests that the magnitude of this risk remains to be defined.