Zelnik M, Kantner J F
Fam Plann Perspect. 1978 May-Jun;10(3):135-42.
About 780,000 teenagers experience a premarital pregnancy each year. If they weren't using contraception, an additional 680,000 would become pregnant--a total of 1,460,000. However, if all who did not want a baby were practicing contraception consistently, we could reduce the number of pregnancies by at least 313,000. Only 467,000 would become pregnant, and half of these pregnancies would be wanted.
每年约有78万青少年经历婚前怀孕。如果他们没有采取避孕措施，还会有68万人怀孕——总计146万人。然而，如果所有不想生孩子的人都能持续采取避孕措施，我们至少可以将怀孕人数减少31.3万。只有46.7万人会怀孕，而且其中一半的怀孕是他们想要的。
