Pocket ObGyn – Contraception & Sterilization
See Abbreviations
Epidemiology (Contraception 2011;83:397)
- ~50% of pregnancies in US are
- PRAMS: 33% of w/ unintended Preg did not think they could get pregnant at the time of conception; 22% stated their partner did not want to use contraception; 16% cited side effects; 10% cited
- Contraceptive efficacy should be compared to 85% unprotected Preg rate in 1 Assessed by perfect (failure rate if used exactly according to guidelines) & typical use (failure rate for the usual compliance).
| Contraceptive methods (*, see also below) | |||
| Method | Perfect use | Typical use | Primary mech of action |
| Sterilization | |||
| Female* | <1% | <1% | Mechanical obstruction |
| Male
Outpt procedure (urology) |
<1% | <1% | Mechanical blockade |
| Long-acting reversible contraception (LARC) | |||
| Etonogestrel implant* (Implanon/Nexplanon) | <1% | <1% | Cervical mucus thickening |
| Levonorgestrel IUD* (Mirena) | <1% | <1% | Cervical mucus thickening, sterile inflamm rxn |
| Copper T IUD* (ParaGard) | <1% | <1% | Sterile inflamm rxn, interferes w/ sperm fxn |
| Combined hormonal | |||
| OCPs* | <1% | 9% | Estrogen-induced inhibition of the midcycle gonadotropin surge prevents ovulation |
| Patch* | <1% | 9% | Estrogen-induced inhibition of the midcycle gonadotropin surge prevents ovulation |
| Vaginal ring* | <1% | 9% | Estrogen-induced inhibition of the midcycle gonadotropin surge prevents ovulation |
| Barrier | |||
| Male condom
¯ STI/HIV infxns |
2% | 18% | Mechanical obstruction for sperm |
| Method | Perfect use | Typical use | Primary mech of action |
| Female condom
¯ STI/HIV less than male condom |
5% | 21% | Mechanical obstruction for sperm |
| Diaphragm + spermicide* | 6% | 12% | Mechanical & chemical obstruction for sperm |
| Cervical cap* | 9–26% | 16–32% | Mechanical obstruction for sperm |
*Special Considerations
- WHO or CDC criteria for contraceptive considerations w/ medical problems, see cdc.gov/reproductivehealth/unintendedpregnancy/usmec.htm
- Female sterilization (Am J Obstet Gynecol 1996;174:1161):
Postpartum salpingectomy: Most effective method of female sterilization; after deliv.
Interval sterilization: Sterilization at other than postpartum period.
Unipolar coagulation is the most effective method of laparoscopic female sterilization.
Hysteroscopic sterilization (Essure) was not available for the CREST study, but is highly effective, outpt. Minimally invasive method w/o limitations by BMI, adhesive dz. Requires confirmation of tubal occlusion w/ hysterosalpingogram at 3 mo.
• Combined hormonal methods (= estrogen + progestin):
Side effects – breakthrough bleeding, breast tenderness, HA, nausea/vomiting.
OCPs: Both estrogen & progesterone or progesterone-only pills. Can interact w/ other meds (Abx, antiretrovirals, antiepileptics) ® potential ¯ efficacy of either or both meds. Useful for menorrhagia, dysmenorrhea, hirsutism, & acne. ¯ risk of endometrial & ovarian cancer. Monophasic vs. multiphasic preparations are avail- able. Monthly vs. continuous dosing is feasible, continuous dosing may be prefer- able for cyst formation prevention, endometriosis, PMS/PMDD, lifestyle reasons.
Contraceptive patch: Replaced weekly ´ 3 w then removed for 1 w (menses).
thromboembolic events compared to combined OCPs.
Vaginal ring: Placed intravaginally ´ 3 w then removed for 1 w (menses). Small
in vaginitis, vaginal discharge, & leukorrhea compared to OCPs.
• Progestin-only methods:
Mech of action: Thickened cervical mucus, thinned endometrium, ovulation inhib Side effects: Breakthrough bleeding, acne, follicular cysts, wt gain, mood changes POP: Preg rate <1% perfect use, 9% typical use. Must be taken every day. Shorter
half-life, therefore missed doses more signif.
DMPA: Preg rate <1% perfect use, 6% typical use. One intramuscular or subcutane- ous injection every 90 d (12 w). Side effects:Wt gain 3–6 kg/y, esp in obese adols,
¯ BMD, but reversible after discontinuation (DEXA scan not recommended).
Etonogestrel implant (Implanon/Nexplanon): Placed in upper arm, in-office, effective for 3 y. Side effects: Breakthrough bleeding common ® major reason for early discontinuation, no ¯ BMD like DMPA, risks of insertion include pain, bleeding, infxn, expulsion, & difficult removal.
Levonorgestrel IUD (Mirena): Inserted in-office, lasts for 5 y. Effective for men- orrhagia, dysmenorrhea, endometriosis, endometrial hyperplasia, & possibly Grade 1 Stage I endometrial cancer. Adolescence, nulliparity, prev STI, & prev ectopic Preg are not contraindications to IUD placement. ectopic Preg w/ IUD, but overall rate of ectopic ¯ due to decreased Preg.
• Nonhormonal methods
Copper IUD: Inserted in-office. Effective for 10 y. Does not impact menstrual regularity, but may cause slightly heavier menses. Adolescence, nulliparity, prev STI, & prev ectopic Preg are not contraindications to IUD placement.
Diaphragm with spermicide: Requires annual fitting, not common in US. Refit if recent Preg or change in wt. Increases risk of urinary tract infxn. Insert 6 h prior to intercourse, remove 6–24 h after intercourse.
Cervical cap: Requires annual fitting, not common in US. Insert 20 min to 4 h prior to intercourse, remove 24–36 h after intercourse.
Withdrawal: Preg rate: 4% perfect use, 22% typical use. Used by up to 56% of women using contraception, usually secondary in conjunction w/ condoms.
Lactational amenorrhea: Preg rate: 2% perfect use, 5% typical use. Effective for 1st 6 mo postpartum only if exclusive breast-feeding (only nutrition for infant), breast-feeding every 4 h during the day & at least every 6 h at night, no menses if ³56 d postpartum.
Rhythm method: Preg rate: 0.4–5% perfect use, 12–23% typical use. Relies on regular menstrual cycles & the limited viability of ova/sperm w/o fertilization. Can use menstrual calendars, cervical mucus changes, basal body temperature, or ovulation kits to avoid intercourse during midcycle fertile days.
Emergency Contraception (EC)
Definition (Obstet Gynecol 2010;115:1100)
- Use of drugs or a device (IUD) as an emergency measure to prevent
- Intended for occasional or back-up use, not as a primary contraceptive
- Indications: No contraception used during sexual intercourse w/i the prev 120 Contraceptive failure or incorrect use of a contraceptive w/i the prev 120 h including condom breakage, 2 missed combined OCPs, POP taken more than 3 h late, 2 w late for DMPA injection, dislodgement of cervical cap/diaphragm/skin patch/vaginal ring, expulsion of IUD.
- Access: Physicians should be aware of national & state laws regarding the availability of & prescribing emergency Available w/o a prescription to people of age 17 or older.
Mechanism of Action
- May include 1 or more of the following: Inhibition or delay of Interference w/ tubal transport or fertilization. Prevention of implantation. Regression of corpus luteum.
- EC does not interrupt Preg & is ineffective after Preg has been
- Efficacy: 75% Preg rate reduction w/ the use of oral EC (if 1000 women had intercourse in the middle 2 w of their cycle, 80 would normally become pregnant but w/ use of oral EC the rate is reduced to 20). Efficacy influenced by:Time from unprotected intercourse to Pt’s BMI: 2–4´ higher risk of Preg if overweight or obese for oral EC.Timing of unprotected intercourse to day of cycle. Further intercourse after use of EC (4´ higher risk vs. those that did not report further intercourse).
Treatment and Medications (Cochrane 2008;2:3)
- Physical exam & lab tests not req prior to Exclude Preg esp before IUD.
- Levonorgestrel (Plan B): 5 mg PO in a single dose. Effective up to 120 h from unprotected intercourse, though most effective w/i 1st 72 h. 98% of pts menstruate w/i 21 d (mean 7–9 d). Administer Preg test if no menses w/i 28 d.
Side effects – irreg bleeding, nausea/vomiting (give antiemetics). Redose if vomiting w/i 2 h of administration.
- Ulipristal (Ella): 30 mg PO in a single Selective progesterone receptor modulator. Effective up to 120 h from unprotected intercourse. Likely more effective than levonorgestrel from 72–120 h after unprotected intercourse.
- Copper IUD (ParaGard): Must be inserted w/i 120 h from unprotected More effective in overweight/obese women than levonorgestrel. Provides long-term, effective contraception along w/ EC.