Use of combination estrogen–progestin hormonal methods (OCs, the patch, and the ring) is generally not advised during lactation because they reduce the amount and quality of breast milk. Combination hormonal methods can be used after 6 weeks, once milk production is established. Progestin-only OCs, implants, and injectable contraception do not affect milk quality or quantity (16). Labeling of the U.S. Food and Drug Administration (FDA) and guidelines from the American College of Obstetricians and Gynecologists suggest that progestinonly OCs can be started 2 to 3 days postpartum, whereas depot medroxyprogesterone acetate (Depo Provera) injections or implants can begin at 6 weeks (19). These recommendations are not based on any observed adverse effect of early administration, and many maternity programs begin injectable contraception with progestin at the time of hospital discharge. Barrier methods, spermicides, and the copper T380A intrauterine device (IUD) (ParaGard) are good options for nursing mothers. Because levonorgestrel implants have no adverse effect on breastfeeding, none should be expected from the levonorgestrel T IUD, which releases levonorgestrel but produces lower blood levels than the implants.
Fertility Awareness Periodic abstinence, described as “natural contraception” or “fertility awareness,” requires avoiding intercourse during the fertile period around the time of ovulation. A variety of methods are used: the calendar method, the mucous method (Billings or ovulation method), and the symptothermal method, which is a combination of the first two methods. With the mucous method, the woman attempts to predict the fertile period by feeling the cervical mucus with her fingers. Under estrogen inﬂuence, the mucus increases in quantity and becomes progressively more slippery and elastic until a peak day is reached. The mucus then becomes scant and dry under the inﬂuence of progesterone until onset of the next menses. Intercourse may be allowed during the “dry days” immediately after menses until mucus is detected. Thereafter, the couple must abstain until the fourth day after the “peak” day.
In the symptothermal method, the first day of abstinence is predicted either from the calendar, by subtracting 21 from the length of the shortest menstrual cycle in the preceding 6 months, or the first day mucus is detected, whichever comes first. The end of the fertile period is predicted by use of basal body temperature. The woman takes her temperature every morning and resumes intercourse 3 days after the thermal shift, the rise in body temperature that signals that the corpus luteum is producing progesterone and that ovulation occurred. The postovulatory method is a variation in which the couple has intercourse only after ovulation is detected.
A system of hormone monitoring designed to better define the fertile period involves placement of disposable test sticks in a small battery-powered device to detect urinary estrone-3 glucuronide and LH. Changes in these hormones reliably predict the fertile period. These devices (Persona™ and Clearblue Easy Fertility Monitor™) can serve as aids both to becoming pregnant and to avoiding it (20). Persona™ is marketed in Europe for contraception. It is reported to have a correct use effectiveness of 94% in avoiding pregnancy. Clearblue Easy™ (CEFM) is approved in the United States as an aid to becoming pregnant but is used off label to avoid pregnancy. Exact effectiveness rates are not known. The CEFM is used in the Marquette method, which combines observation of cervical mucus changes with the CEFM results. A correct use pregnancy rate of 2% and a typical use pregnancy rate of 12% were reported (21).