Cytogenetic study of 677 spontaneous abortions.

INTRODUCCION: The human reproduction is a relatively inefficient process. In the 15 to 20% of the pregnancy clinically diagnosticated finish in spontaneous abortions. The great emotional impact, that in many times is worst by the lack of diagnostic. OBJECTIVE: Describe experience of the Cytogenetic Laboratory of Clínica Sanatorio Alemán of Concepción Chile and determinate the frequency of alteration and his relationship with maternal age. MATERIAL AND METHOD: 677 samples of tissue of spontaneous abortions, taked from July, 1996 to April, 2009. It is a descriptive work; the samples are chorionic villous, cultivated in standard solutions. RESULTS: Of 677 samples in 259 was found a normal cariotype (38.3%). In 418 was found some type of chromosome aberrations (61.7%). The distribution of the abnormal result is the follow: 265 trisomies (63.4%), 83 polyploidy (19.8%), 48 monosomy (11.5%) and 22 abnormalities structures (5.3%). Of the trisomies the most recurrent is 16 trisomy with the 34.4%, follow by the 21 trisomy with 13.6% and the 22 trisomy with 12.8%. In the statistic analysis we found a statistically significant relation between the age of the mother (<38 years) and the development of chromosomal alterations (p<0.0001). DISCUSSION: The 61.7% of abortions show some cytogenetic alteration. The 16 trisomies were the most frequent, agreeing with the literature. The trisomy 21 was more common than published to date. In older women is most frequent found chromosome aberrations (p<0.0001).