Back-up methods are not usually required, unless the woman is taking rifampin/rifampicin.

With the exception of rifampin/rifampicin, antibiotics are unlikely to significantly reduce the effectiveness of POPs in breastfeeding women.

If the breastfeeding woman is taking rifampin/rifampicin, she should know that rifampin/rifampicin:

• passes through breastmilk (with potential infant side effects),
• may increase breakthrough bleeding, and
• lowers progestin levels, possibly significantly reducing the effectiveness of POPs.

Rifampin/rifampicin, which is used primarily for treating tuberculosis, induces hepatic enzymes and increases the liver metabolism of progestins, thus decreasing the effectiveness of POPs. The enzyme-inducing effects of rifampin/rifampicin last about four weeks after short-term use and eight weeks after long-term use.

Griseofulvin, an anti-fungal antibiotic and another hepatic enzyme inducer, has not been proven to reduce POP effectiveness in humans, but may increase menstrual irregularities.

Rifampin/rifampicin is passed in breastmilk (milk:plasma ratio of 0.2 to 0.6). Griseofulvin may also be passed in breastmilk. Infant exposure to rifampin/rifampicin or griseofulvin is appropriate only when the maternal benefits outweigh the potential risks to the infant.

1. Back DJ, Orme ML. Drug interactions. In: Goldzieher JW, Fotherby K (editors.). Pharmacology of the Contraceptive Steroids. New York: Raven Press, 1994:407-25.
2. Fotherby K. Interactions with oral contraceptives. American Journal of Obstetrics and Gynecology 1990;163:2153-9.
3. Drug Facts and Comparisons. St. Louis: Facts and Comparisons, June 1996, p. 358 and October 1990, p.387a
4. World Health Organization. Improving access to quality care in family planning: medical eligibility criteria for contraceptive use. Geneva: WHO, 1996.
5. Baciewicz AM, Self TH, Bekemeer WB. Update on rifampin drug interactions. Archives of Internal Medicine 1987;147(3):565-8.

Yes, usually. The common anticonvulsants, hydantoins (e.g., phenytoin), barbiturates (e.g., phenobarbital, primidone), and probably carbamazepine significantly decrease the effectiveness of oral contraceptives. POPs are not recommended if using these enzyme-inducing anticonvulsants.

Additionally, because anticonvulsants are excreted in breastmilk, and because there is a potential for serious adverse reactions in nursing infants, women taking hydantoins, barbiturates, or carbamazepine for chronic seizure control may be advised to explore safe alternatives to breastfeeding.

Injectable contraceptives, such as Depo Provera^®, will be effective despite anticonvulsant use, but infant exposure to the anticonvulsants will continue.

Non-hormonal methods will continue to be effective despite anticonvulsant use.

Because of the dangers of fetal exposure to most anticonvulsants, full protection against pregnancy is essential. Although increased doses of POPs might be effective, they might also further increase bleeding irregularities.

1. Mattson RH, Rebar RW. Contraceptive methods for women with neurologic disorders. American Journal of Obstetrics and Gynecology 1993;168:2027-32

If a woman ingests hydantoins, barbiturates, or carbamazepine, her breastmilk will contain significant quantities of these substances. In areas where safe alternatives to breastfeeding exist, and where maternal seizures cannot otherwise be controlled, women on long-term anti-seizure medications may be advised to consider safe alternatives to breastfeeding, to avoid chronic infant drug exposure.

1. Drug Facts and Comparisons. St. Louis: Facts and Comparisons, July 1996, pp. 282-4.
2. World Health Organization. Improving access to quality care in family planning: medical eligibility criteria for contraceptive use. Geneva: WHO, 1996.
3. Anderson GD, Graves NM. Drug interactions with antiepileptic agents. CNS Drugs 1994;2(4):268-79.

No back-up is needed.

There is no evidence that anti-malarial medications reduce the effectiveness of OCs.

Chloroquine and related anti-malarials are excreted in breastmilk.

A nursing infant may consume about half of a mother's 300 mg chloroquine dose over 24 hours; the maternal milk: blood ratio may be about 0.36. Children are especially sensitive to chloroquine and primaquine.

1. Drug Facts and Comparisons. St. Louis: Facts and Comparisons June 1996, pp. 358 and 387a.

No back-up is needed.

However, if a breastfeeding woman has resumed menstruating and is beginning the pills later than the first seven days of her cycle, some programs recommend that she use a back-up method for seven days after beginning POPs.

1. Chretien FC, Sureau C, Neau C. Experimental study of cervical blockage induced by continuous low-dose oral progestogens. Contraception 1980;22:445-56.
2. Kesseru-Koos E. Influence of various hormonal contraceptives on sperm migration in vivo. Fertility and Sterility 1971;22:584-603.
3. Moghissi KS, Syner FN, McBride LC. Contraceptive mechanism of microdose norethindrone. Obstetrics and Gynecology 1973;41:585-94.

If the breastfeeding woman is still amenorrheic, missed pills are of minimal consequence.

For a breastfeeding woman who has already returned to menses, if two or more pills are missed, the woman should:

• resume taking a pill as soon as she remembers,
• take the next pill at the regular time that day (for added protection), and
• use a back-up method or abstinence for 48 hours (some programs recommend use of a back-up method for up to seven days).

The most immediate effect of POPs is on cervical mucus, each tablet offering protection for approximately 24 hours. Clinical trial data indicate that the pregnancy protection conferred by POP use during breastfeeding is high, indicating a synergistic pregnancy prevention effect for breastfeeding while using POPs. In addition, women in lactational amenorrhea have additional protection due to their lowered fecundity.

1. Kesseru-Koos E. Influence of various hormonal contraceptives on sperm migration in vivo. Fertility and Sterility 1971;22:584-603.
2. Dunson T, McLaurin V, Grubb G, Rosman A. A multicenter clinical trial of a progestin-only oral contraceptive in lactating women. Contraception 1993;47:23-35.
3. Kennedy KI, Visness C. Contraceptive efficacy of lactational amenorrhoea. Lancet 1992;339:227-30.

If a woman is breastfeeding and amenorrheic, no back-up method is needed since the synergistic effect of both breastfeeding and POP use should provide sufficient pregnancy protection.

If a breastfeeding woman has resumed menstruating, some programs recommend use of a back-up method for 48 hours or for 7 days after the severe vomiting or diarrhea stops.

1. Dunson T, McLaurin V, Grubb G, Rosman A. A multicenter clinical trial of a progestin-only oral contraceptive in lactating women. Contraception 1993;47:23-35.
2. Orme M, Back DJ, Breckenridge AM. Clinical pharmacokinetics of oral contraceptive steroids. Clinical Pharmacokinetics 1983; 8:95-136.
3. Kennedy KI, Visness C. Contraceptive efficacy of lactational amenorrhoea. Lancet 1992;339:227-30.