Initiating Contraceptive Therapy

Combined Oral Contraceptives (COCs)

The Centers for Disease Control and Prevention recommends that COCs can be started at any time during the menstrual cycle if pregnancy is reasonably excluded, but starting within the first 5 days of menstrual bleeding eliminates the need for backup contraception 1
If started more than 5 days after menstrual bleeding begins, backup contraception, such as condoms, is required for 7 days 2
In cases of amenorrhea, COCs can be initiated at any point if pregnancy is excluded, with backup contraception required for 7 days 1, 2
Postpartum women who are not breastfeeding can start COCs immediately, while those who are breastfeeding should consider alternative methods or delay initiation 1, 2

The Centers for Disease Control and Prevention recommends that POPs can be started within the first 5 days of menstrual bleeding without the need for backup contraception 1
If started more than 5 days after menstrual bleeding began, abstain from intercourse or use backup contraception for 2 days 1
POPs can be initiated at any time if pregnancy is reasonably excluded, with a requirement for only 2 days of backup contraception when started late in the cycle 1, 3

The American College of Obstetricians and Gynecologists and the Centers for Disease Control and Prevention advise against delaying contraceptive initiation until the next menstrual period, as this increases the risk of unintended pregnancy 1

The American College of Obstetricians and Gynecologists and other guideline societies support the use of progestin-only pills (POPs), which require only 2 days of backup contraception when started after day 5 of menses, compared to 7 days for combined oral contraceptives (COCs), due to the rapid onset of POPs' contraceptive effects on cervical mucus 4
In special clinical scenarios, such as amenorrhea, progestin-only pills can be started anytime with 2 days of backup contraception, as recommended by guideline societies 5

The Centers for Disease Control and Prevention (CDC) recommends that COCs can be started immediately at any point in the cycle if pregnancy is reasonably excluded, but this requires 7 days of backup contraception 6
Postpartum women (not breastfeeding) can start COCs immediately, with backup contraception for 7 days if ≥21 days postpartum and menstrual cycles have not returned 6
Postabortion women can start COCs within the first 7 days, including immediately postabortion, without need for backup contraception if started immediately 6

The CDC recommends that POPs require only 2 days of backup contraception when started late in the cycle, due to the rapid onset of contraceptive effects on cervical mucus 6
Postpartum women, including breastfeeding women, can start POPs immediately (≥21 days postpartum), with 2 days of backup contraception if menstrual cycles have not returned 6
Postabortion women can start POPs within the first 7 days, including immediately, with 2 days of backup contraception unless started at the time of surgical abortion 6

When pregnancy status is uncertain, the benefits of starting OCPs likely exceed any risk; therefore, starting should be considered at any time, with a follow-up pregnancy test in 2-4 weeks 6
The CDC recommends that OCPs can be started immediately when switching from another contraceptive method without waiting for the next period, though backup contraception requirements depend on when in the cycle the switch occurs (7 days for COCs, 2 days for POPs if >5 days since menstrual bleeding started) 6
Among healthy women, no examinations or tests are needed before OCP initiation, though baseline weight and BMI measurement may be useful for monitoring 6

The Centers for Disease Control and Prevention (CDC) recommends that oral contraceptives can be started at any time if it is reasonably certain the woman is not pregnant, and waiting for the next menstrual period is unnecessary 7
The American College of Obstetricians and Gynecologists (ACOG) and CDC discourage delaying contraception until the next period arrives, as this increases the risk of unintended pregnancy 7

For Combined Oral Contraceptives (COCs), backup contraception (condoms) or abstinence from sex is required for 7 consecutive days after starting pills, as recommended by the CDC 7
For Progestin-Only Pills (POPs), backup contraception is only needed for 2 days, due to the quicker onset of contraceptive effects on cervical mucus, as stated by the CDC [8] [9]

Emergency contraception should be considered if unprotected sex occurred within the last 5 days, and should be offered before or concurrent with starting regular birth control pills, as recommended by the CDC 7
Starting regular birth control pills does not provide protection against pregnancy from recent unprotected intercourse, emphasizing the need for emergency contraception if indicated 7

A follow-up pregnancy test should be scheduled in 2-4 weeks after starting birth control pills, as recommended by the CDC, to ensure no pregnancy was missed [9] [10]
The CDC states that when there's any uncertainty about pregnancy status, the benefits of starting contraception exceed the risks, but follow-up testing is prudent [9] [10]

No pelvic exam or additional testing is required before starting pills in healthy women, as stated by the CDC 11