RESUMO
Objective To evaluate the possibility of elevating the age line for pregnant women with advanced age to conducted amniocentesis .Methods A retrospective cohort study was performed .The information of 5 176 advanced age pregnant women in July 2003 to August 2015 from Ningbo Women and Children Hospital were collected and analyzed .Grouped the patients by age , using chi-square analysis , comparing the difference of abnormal rate of target chromosomes (13, 18, 21) and sex chromosomes (X and Y) between the adjacent two age groups .Results Total of 15 408 cases were screened.Among these, 262 cases were diagnosed with abnormal chromosome .The positive rate was 1.70%.Total of 5 176 advanced age pregnant women were included , 82 women were found with abnormal target chromosomes (13, 18, 21) and sex chromosome.The positive rate was 1.58%(82/5 176).For age groups, the positive rates were 0.95%(11/1 156), 0.94%(9/954), 0.87%(10/1 144), 2.16%(14/648), 2.16%(10/464), 2.51%(10/399) and 4.38%(18/411) respectively.Chi-square analysis results showed that the positive rate between group of 37 and 38 was significant difference (chi-square value of 5.181,P value of 0.023).There were no significant differences among all remained groups ( chi-square value: <0.001, 0.028, <0.001, 0.117, 2.129 respectively, P value: 0.985, 0.868, 0.995, 0.733, 0.145 respectively ) .Conclusion It is worthwhile to elevate the age of pregnant women up to 38 years old as the age line for the indications of amniotic fluid chromosome analysis .
