Contraception and Lactation

Joyce King, CNM, FNP, PhD

Disclosures

J Midwifery Womens Health. 2007;52(6):614-620. 

In This Article

Methods of Contraception

In choosing a method of contraception, it is important that it not interfere with lactation or have negative effects on the infant. Nonhormonal methods of contraception, such as barrier methods or the copper intrauterine device (IUD), are the preferred choice for nursing mothers, because hormones in some contraceptive methods may interfere with lactation, and the transfer of hormones into milk poses a theoretical risk to the infant.[2] There are numerous nonhormonal methods available that have no effect on production of milk or on infant growth and development. Methods like the diaphragm, condoms, spermicidal foams and jellies, and copper IUDs provide reversible contraception, while vasectomy and tubal ligation are permanent methods.

Intrauterine Devices

IUDs are long-term contraceptive methods with high efficacy. Some have raised concerns that the uterine contractions that accompany breastfeeding may cause expulsion of an IUD. The results of an early study showed that breastfeeding does not increase the risk of IUD expulsion whether the device is inserted within 10 minutes of delivery or more than 42 days postdelivery.[13] The copper IUD has no effect on breast milk copper concentrations.[14] Shikary et al.[15] noted that levonorgestrel in the levonorgestrel-releasing intrauterine system Mirena (Bayer HealthCare Pharmaceuticals, Wayne, NJ) does transfer from maternal serum into the breast milk, and that 11.8% of that transfers into the infant circulation. They found less of the hormone transferred into the infant from the oral form of levonorgestrel than from either a subdermal levonorgestrel implant or the levonorgestrel IUD.

Tubal Ligation

If a tubal ligation is performed using general anesthesia, the mother should breastfeed just before the procedure to minimize the length of infant fast, and can then resume breastfeeding immediately following surgery with the following guidelines: 1) the mother should be awake and alert; 2) short-acting benzodiazepines (e.g., Ativan), muscle relaxants, inhalation agents, and local anesthetics are most likely safe, but meperidine (Demerol) or prolonged use of diazepam (Valium) should be avoided.[16,17,18] It is important that the anesthesiologist be aware that the surgical patient is breastfeeding in order to make the best decision about the choice of anesthesia.

Natural Family Planning Methods

Natural family planning may be a contraceptive option for lactating women who prefer such a method. Studies of cervical secretions in breastfeeding women indicate that mucus changes indicating fertility are reliable during lactation, and that charting should be carried out in the usual manner.[19] In a study of 419 postpartum breastfeeding women who evaluated and charted the characteristics of their cervical mucus each day, Perez[19] observed that 50% of the women detected mucus by the fourth month; mucus was noted approximately 2 months before the first menses. It was also noted that as the women moved from total breastfeeding to partial breastfeeding or to complete weaning, the number of days of cervical mucus increased.

Hormonal Methods

There are some concerns about the use of hormonal contraceptive methods in lactating women. It is hypothesized that hormones ingested by the infant in breast milk may result in circulating levels that are higher than expected because of an immature liver that cannot metabolize the hormones, immature kidneys that may not be able to excrete the hormones, and a plasma-binding capacity that may be low, resulting in higher levels of free and biologically active hormones.[11] It is also important to note, however, that hormones are not well absorbed from breast milk in the newborn infant.[11] Patel et al.[20] studied 30 breastfeeding women using levonorgestrel-containing oral contraceptives and their breastfeeding infants at 4, 12, and 24 weeks of age. At 4 weeks, the infants could neither absorb nor metabolize the levonorgestrel; at 12 weeks, the infants could metabolize the hormone more efficiently than it could absorb it; by 24 weeks of age, the infants could both absorb and metabolize the drug. Virutamasen et al.[21] observed that no metabolites of medroxyprogesterone acetate were found in the urine of infants whose mothers were given Depo-Provera (Pfizer, Inc., New York, NY) on days 42 and 126 postpartum. Another study examining progestin-only pills concluded that very low amounts of the hormones are transferred into breast milk.[22] According to Halderman,[11] there is minimal evidence that exposure to exogenous hormones is harmful to the infant, but also there is no evidence to support its safety.

When to initiate hormonal contraception in the postpartum woman is also debated. Most experts have traditionally delayed starting hormonal contraception until the 6-week postpartum visit, after lactation is well established. This delay has been based on the theoretical concern that hormonal contraceptives containing estrogen and progestin may impair lactation through their effect on the action of prolactin on the breast. As noted above, placental estrogen and progesterone inhibit prolactin activity during pregnancy. After delivery of the placenta, when estrogen and progesterone levels markedly decrease, prolactin levels increase and milk production is initiated.[4] There is a theoretical concern that giving hormones before 6 weeks postpartum, or before breastfeeding is well established, could interfere with optimal lactation.[2]

Progestin-only contraceptives, including oral contraceptives, the Depo-Provera contraceptive injection (DMPA; Pfizer, Inc., New York, NY), and etonogestrel-releasing implant Implanon (Organon USA, Inc., Roseland, NJ) do not have adverse effects on lactation, although there is still controversy regarding early use in breastfeeding women.[11] Product labeling for DMPA recommends initiation at 4 to 6 weeks after delivery, regardless of breastfeeding status. This recommendation is based on research conducted in family planning clinics where the patient's initial visit after delivery was scheduled at that time.[11] The World Health Organization (WHO) noted in multinational prospective studies that followed 2466 breastfeeding mothers and their infants that progestin-only methods of contraception started 6 weeks postpartum did not adversely affect infant development[23] or infant growth.[24]

Another WHO study compared progestin-only contraceptive methods that were initiated at 6 weeks postpartum to nonhormonal methods of contraception (e.g., IUD). After 6 weeks of treatment, there was no decrease in milk volume in the women using a progestin-only minipill when compared to the nonhormonal methods. Milk volume was measured using the pump-extraction method for milk collection. What is interesting is that at 18 weeks post-initiation of treatment, the progestin-only pill group had a 12% decline in milk volume compared to only a 6.1% decline in women who were using nonhormonal methods of contraception. This same study showed that women using DMPA had an increase in milk production between the 16- and 20-week visits when compared to women using progestin-only minipills or nonhormonal methods of contraception.[25]

Taneepanichskul et al[26] compared the effects of Implanon, a single-rod, etonogestrel-releasing contraceptive implant, with a nonmedicated IUD on lactation and infant growth (n = 80). Healthy lactating women chose either the contraceptive implant or the IUD for insertion 28 to 56 days postpartum. The data showed that etonogestrel had no effect on infant growth during the 3-year follow-up period of the study. The researchers concluded that Implanon appears to be a safe contraceptive option for breast-feeding women and their infants.[26]

Shaamash et al.[27] conducted a prospective, controlled, randomized trial (n = 320) comparing the levonorgestrel-20 µg intrauterine system Mirena (Bayer HealthCare Pharmaceuticals) with the copper T380A intrauterine device and their effect(s) on breastfeeding performance, as well as infant growth and development during the first year postpartum. No statistical differences were found between the two groups with regard to duration of breastfeeding, infant growth (i.e., weight, length, head circumference, mid-arm circumference, and skin fold thickness) or development (i.e., ability to pass the various developmental tests, such as reaching for a dangling object or visually locating a sound).

Another study conducted at two public hospitals in Santiago, Chile, evaluated four methods of contraception: a progesterone vaginal ring (n = 187); progestin-only pills (n = 117); Norplant (Wyeth Pharmaceuticals, Madison, NJ) implants (n = 120); and copper T 380A IUDs (n = 122) in lactating women. The study examined contraceptive performance, duration of lactation, infant growth, duration of lactational amenorrhea, and menstrual patterns during the first year of use. All contraceptives were initiated at day 57 ± 3 postdelivery. All methods were highly effective, with only two pregnancies occurring among users of progestin-only pills during the first 6 months postpartum. The duration of lactation was similar in users of all the methods, as were measurements of infant growth. Women using the progesterone ring, progestin-only pills, and Norplant (Wyeth Pharmaceuticals) implants had a prolonged period of lactational amenorrhea; this was not seen with users of the copper T 380A IUD. Prolonged or frequent bleedings occurred infrequently with all the methods, and very few women discontinued their contraceptive method because of bleeding problems.[28] In response to these numerous studies, the WHO states that there is no restriction on the utilization of progestin-only methods of birth control in breastfeeding women initiated after 6 weeks postpartum.[11]

A less conservative approach is early initiation of progestin-only contraceptive methods. Several studies that evaluated early administration of progestin-only methods, progestin-only pills at 1 week postpartum[29] and DMPA injected at 2 days[30] and 7 days[31] found no differences in infant growth or breastfeeding practices, such as duration of breastfeeding or supplementation, between users of the different progestin-only contraceptives. Boudraoui et al.[32] found that immediate administration of DMPA postpartum in 772 lactating women followed from delivery to 1 year postpartum actually resulted in an increase in the amount of milk and an increase in protein concentration. Karim et al.[33] found that administration of DMPA 7 days postpartum was not only associated with no adverse effects on the amount of milk production or duration of lactation, but the treatment group showed greater infant weight gain than did the control subjects. A 2002 study showed that breastfeeding women using progestin-only methods of contraception that were initiated before hospital discharge had no significant differences in their continuation rates of breastfeeding when compared to breastfeeding women who used nonhormonal methods of contraception. Supplementation because of the perception of insufficient milk production also did not differ between the two groups.[11] This study supports the earlier findings that early initiation of progestin-only methods of contraception has no adverse impact on breastfeeding practices.

It is generally recommended that breastfeeding mothers not use hormonal methods of contraception that contain estrogen (e.g., combined oral contraceptives, the vaginal contraceptive ring, and the contraceptive patch).[34] A WHO trial reported a statistically significant decrease in milk volume in women who took combined oral contraceptives when compared to women who took progestin-only contraceptives.[35] However, there were no significant differences between combined hormone pills and progestin-only pills in milk composition or infant growth.[35] The International Planned Parenthood Federation recommends that combined hormonal contraceptives not be used at all by breastfeeding women. The WHO recommends that if combined hormonal methods are going to be utilized, they should not be initiated until at least 6 months postpartum after breastfeeding skills and patterns are well established.[34] Because of a hypercoaguable state during the early postpartum period, even nonbreastfeeding women should avoid estrogen-containing hormonal contraceptives for at least 3 weeks after delivery.[21,34] A recent systematic review of randomized controlled trials evaluated the effect of combined oral contraceptives and progestin-only contraceptives on lactation.[2] The authors concluded that the data are insufficient to establish any effect of hormonal contraception on either milk quantity or quality and that existing data are inadequate to make an evidenced-based recommendation regarding hormonal contraceptive use for lactating women. After reviewing 50 articles written from 1967 to 2002, only seven reports from five trials met the inclusion criteria set by the review group.[2] Their evaluation of these five trials found that the methodologic quality of all five was poor, and results should be interpreted with caution. The method of measuring milk output, the number of breastfeedings reported in a 24-hour period, and the addition of supplemental foods were not consistent.[2] Small sample sizes and loss to follow-up also were problematic for several studies. Well conducted randomized controlled trials of adequate size are urgently needed to address the effect of hormonal contraception on milk quality and quantity. Within these limitations however, this Cochrane review found no evidence that hormonal contraceptives cause adverse effects on infant growth.[2]

The American College of Obstetricians and Gynecologists' (ACOG)[36] and WHO[35] recommendations for hormonal contraception in breastfeeding women are listed in Table 1 . The ACOG recommendations are based on the manufacturer's prescribing information. Because it has been shown that in certain populations of breastfeeding women there are low continuation rates of breastfeeding and high rates of bottle supplementation,[11,15] and because early initiation of progestin-only methods of contraception do not appear to affect infant growth,[29,30,31] it may be appropriate to initiate progestin-only methods of contraception for women who may be at risk for early return to fertility and unintended pregnancy.

Conclusion

All providers of prenatal care should evaluate the patient's need and desire for postpartum contraception during the last trimester of pregnancy. The choice of contraceptive method and the timing of contraceptive initiation is an essential consideration for the breastfeeding woman. Women who are breastfeeding should be counseled that supplementation, the resumption of menstrual bleeding, and reaching the sixth postpartum month are all associated with increased fertility. The patient's personal contraceptive preferences and lifestyle also must be considered when choosing a method of contraception. Table 2 summarizes the clinical guidelines for provision of contraception to breastfeeding women.[37] The ideal situation is one in which the woman is informed of all the contraceptive alternatives and that she will choose to use a method that has no effect on lactation or the newborn.

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