13,14,15 = 排卵期 (3日).....懷孕機率--71-95% 16,17,18,19,20 = 排卵期後危險期(5日).....懷孕機率--31-70% 21,22,23,24,25,26,27 ,28.....= 後安全期至下次來經.....懷孕機率--5-30% 提倡安全性行為.....要有一套.....濫交SAY NO.....!!!
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