In many early pregnancies, the hCG level will double every 31 to 72 hours. As the pregnancy progresses, hCG levels rise and the doubling time increases. （许多的早孕， 和hCG水平每31-72小时会翻倍， 随着怀孕的进程， HCG水平的上升以及翻倍的时间也会增加。 ）
"Normal" Doubling Time （“正常”翻倍时间）
hCG levels ( hCG水平)
Doubling Time （翻倍时间）
Under 1200 mIU/ml （1200 以下） 31-72 hours （31-72小时）
Between 1200 to 6000 mIU/ml （1200-6000） 72-96 hours （72-96小时）
Over 6000 mIU/ml （6000 以上） more than 96 hours （大于96小时）
hCG levels rise during the first 6 to 10 weeks of pregnancy then decline slowly during the second and third trimesters. （hCG水平在最初的6-10周会上升，之后会逐渐降低）
•The hCG levels will usually double approximately every 48 hours [ 2 days ] for the first four weeks of pregnancy. （hCG 在最初4周常常每48小时（2天）翻倍一次）
•As pregnancy progresses the doubling time increases. By 6 to 7 weeks gestation beta hCG levels may take as long as 84 hours [ 3½ days ] to double. （随着孕期进程，翻倍时间增加。到6-7周，HCG水平需要84小时（3.5天）才翻倍一次）
•The beta hCG may take more than 48 - 72 hours [ 2 to 3 days ] to double in 15% of normal intrauterine pregnancies.（15%的宫内妊娠HCG的翻倍时间超过48-72小时）
•About 17% of ectopic pregnancies have normal doubling times. （17%的宫外孕有正常的HCG翻倍）
