Norethindrone: Side Effects, Uses & Monitoring

Labeled uses

1. Indications. Progestin-only oral contraceptives are indicated for the prevention of pregnancy. 2. Efficacy. If used perfectly, the first-year failure rate for progestin-only oral contraceptives is 0.5%. However, the typical failure rate is estimated to be closer to 5%, due to late or omitted pills. The following table lists the pregnancy rates for users of all major methods of contraception. Table 2: Percentage of Women Experiencing an Unintended Pregnancy During the First Year of Typical Use and the First Year of Perfect Use of Contraception and the Percentage Continuing Use at the End of the First Year. United States. | % of Women Experiencing an  Unintended Pregnancy  within the First  Year of Use | % of Women  Continuing  Use at  One Year 3 | Method  (1) | Typical Use 1 (2) | Perfect Use 2 (3) | (4) |  Chance 4 |  85 |  85 | |  Spermicides 5 |  26 |  6 |  40 |  Periodic abstinence |  25 | |  63 |     Calendar | |  9 | |     Ovulation Method | |  3 | |     Sympto-Thermal 6 | |  2 | |     Post-Ovulation | |  1 | |  Cap 7 | | | |     Parous Women |  40 |  26 |  42 |     Nulliparous Women |  20 |  9 |  56 |  Sponge | | | |     Parous Women |  40 |  20 |  42 |     Nulliparous Wom…