Effect of maternal age on spontaneous abortion during the first trimester in Northeast China

OBJECTIVE: We aimed to determine the relationship between fetal chromosomal abnormalities and maternal age among spontaneous first trimester abortions in women in Northeast China. METHODS: We evaluated 497 chorionic villi samples from patients with a history of spontaneous abortion during the first trimester. We divided the samples into five groups according to the maternal age: <25, 25-29, 30-34, 35-39, and ≥40 years. We identified chromosomal abnormalities by fluorescence in situ hybridization. RESULTS: Among the 497 chorionic samples of spontaneous abortion, 180 (36.22%) had fetal chromosomal abnormalities. Patients aged ≥40 years had a significantly higher percentage (60.61%) of fetal chromosomal abnormalities compared with the other groups. More women in the ≥40 and 35- to 39-year groups had a history of three consecutive miscarriages and 10 kinds of abnormalities. The most frequent aneuploidy was trisomy 22, followed by trisomy 16. CONCLUSIONS: These results revealed that the kinds of fetal abnormalities, numbers of abortions, and chromosomal abnormality rates increased with increasing maternal age. The most common trisomy types in spontaneous abortions were closely related to maternal age. We hypothesize whether the larger probability of chromosomal abnormalities is due to increased mutation rate with maternal age, or due to a worse in-utero conditions.