Levonorgestrel concentrations in maternal and infant serum during use of subdermal levonorgestrel contraceptive implants, Norplant, by nursing mothers

Drugs that affect the fetus and newborn infant via the placenta or breast milk

In general, drugs that are taken by a mother during pregnancy or after birth may be transferred to the fetus or the infant (through breast milk). Many factors are involved that determine the amount of drugs that are transferred and their potential effects on the fetus or infant. A careful assessment of the risk versus benefit is necessary and should be individualized. In the breastfed infant, many measures can be undertaken further so that the amount of drug transferred to the infant is minimized.

Risks and benefits, advantages and disadvantages of levonorgestrel-releasing contraceptive implants

Levonorgestrel-releasing implants are long acting contraceptives, approved for 5 years of continuous use. Two marketed systems, the six capsule Norplant use of tradenames is for product identification purposes only and does not imply endorsement. and the two rod Jadelle, have essentially equal rates of drug release, pregnancy and adverse events over 5 years of use. Randomised clinical trials and controlled cohort observations indicate that for the first 3 years, when pregnancy rates are at or almost zero, no other contraceptive system is more effective, although etonogestrel implants provide equal effectiveness. Annual pregnancy rates rise in the fifth year of continuous use but remain below 1 per 100 women. Annual pregnancy rates of Norplant users remain below 1 per 100 throughout 7 years of continuous use. Levonorgestrel implants provide low progestogen doses; 40-50 microg/day at 1 year of use, decreasing to 25-30 microg/day in the fifth year. Serum levels of levonorgestrel at 5 years are 60-65% of those levels measured at 1 month of use. Adverse effects with levonorgestrel implants are similar to those observed with progestogen only and combined oral contraceptives. Risks of ectopic pregnancy, other pregnancy complications and pelvic inflammatory disease are reduced in comparison with those of women using copper or non-medicated intrauterine devices. Risks of developing gallbladder disease and hypertension or borderline hypertension, although small, are about 1.5 and 1.8 times greater, respectively, in women using levonorgestrel implants than in women not using hormonal contraception. Other serious diseases have not been found to occur significantly more frequently in levonorgestrel implant users than in women not using hormonal contraception. The great majority of levonorgestrel implant users experience menstrual problems, but serious bleeding problems are not more frequent than in controls. Other health problems reported more frequently by levonogestrel implant users than by women not using hormonal contraception in a study of 16000 women included skin conditions, headache, upper limb neuropathies, dizziness, nervousness, malaise, minor visual disturbances, respiratory conditions, arthropathies, weight change, anxiety and non-clinical depression. Clinical depression is not more frequent in women using implants compared with those not using hormonal contraception (i.e. using intrauterine devices, sterilisation). Removal problems occur less frequently with Jadelle than with Norplant. The mean removal time for Jadelle is half that of Norplant. Levonorgestrel implants in nationally representative scientific samples, in randomised trials, and in controlled cohort studies have continuation rates as high as or higher than any other reversible contraceptive over a duration of 5 years. This would imply that the satisfaction women derive from the contraceptive effectiveness of levonorgestrel implants greatly outweighs the dissatisfaction that may accompany menstrual disturbances and other adverse effects associated with implants.

Health and growth of infants breastfed by Norplant contraceptive implants users: a six-year follow-up study

The objective of the study was to evaluate safety to infants whose mothers used Norplant levonorgestrel implants during breastfeeding. A nonrandomized clinical trial design was used. Participants were 220 and 222 healthy breastfed infants of mothers initiating use of Norplant or T-Cu IUD, respectively, at 55 days to 60 days postpartum. Infants were followed from birth through age 6 years. Breastfeeding pattern, infant growth, and disease events were recorded monthly in the first year, three-monthly in the second, and annually thereafter. Most mothers continued use of Norplant (96.4%) and T-Cu (94.1%) during lactation, and 2140 months of infant exposure to levonorgestrel were accumulated. Breastfeeding pattern and infants growth, from admission through age 6 years, were similar in both groups. In the first year, breastfed infants in the Norplant group had higher incidence rates (p < 0.05) of mild episodes of respiratory infections (adjusted RR 1.17, CI 1.08-1.27), skin conditions (adjusted RR 1.46, CI 1.20-1.79), and eye infections (unadjusted RR 1.49, CI 1.03-2.18) than the control group. Later on, a higher proportion of infants in the T-Cu group showed neurological conditions. Although breastfeeding patterns and infant growth is not affected by Norplant use during lactation, the effect on infants' health of steroidal contraception should be further evaluated.

Contraceptive implants and lactation

The safety and efficacy of four contraceptive implants, plant, Implanon, Nestorone and Elcometrine, have been evaluated during use in the postpartum period by lactating women. These implants provide highly effective contraceptive protection with no negative effect on breastfeeding or infant growth and development. Breastfeeding women initiating Norplant use in the second postpartum month experience significantly longer periods of amenorrhea than do untreated women or intrauterine device users. After weaning, the bleeding pattern is similar to that observed in non-nursing women. Norplant use does not affect bone turnover and density during lactation. Norplant and Implanon release orally active progestins while Nestorone and Elcometrine implants release an orally inactive progestin, which represents an advantage since the infant should be free of steroidal effects. The infant's daily intake of steroids (estimated from concentrations in maternal milk during the first month of use) range from 90 to 100 ng of levonorgestrel (Norplant), 75-120 ng of etonogestrel (Implanon), and 50 ng and 110 ng of Nestorone (Nestorone and Elcometrine implants, respectively). Nursing women needing contraception may use progestin-only implants when nonhormonal methods are not available or acceptable. Implants that deliver orally active steroids should only be used after 6 weeks postpartum to avoid transferring of steroids to the newborn.

Transfer of drugs and other chemicals into human milk

The American Academy of Pediatrics places emphasis on increasing breastfeeding in the United States. A common reason for the cessation of breastfeeding is the use of medication by the nursing mother and advice by her physician to stop nursing. Such advice may not be warranted. This statement is intended to supply the pediatrician, obstetrician, and family physician with data, if known, concerning the excretion of drugs into human milk. Most drugs likely to be prescribed to the nursing mother should have no effect on milk supply or on infant well-being. This information is important not only to protect nursing infants from untoward effects of maternal medication but also to allow effective pharmacologic treatment of breastfeeding mothers. Nicotine, psychotropic drugs, and silicone implants are 3 important topics reviewed in this statement.

Implantable contraception

Although levonorgestrel contraceptive implants have been available for over 15 years, innovations have only recently led to a wider choice. These new implants offer easier insertion and removal and other advantages depending on the type of progestin. Implants prevent pregnancy by several mechanisms, including inhibition of ovulation and luteal function and alteration of cervical mucus and the endometrium. The high efficacy and ease of maintenance make implants an ideal contraceptive for many women, including adolescents, a population that uses implants infrequently but reports high satisfaction. Implants are appropriate for women who are breastfeeding, who have contraindications to estrogen, or who have diseases such as diabetes, hypertension, sickle cell anemia, or an HIV infection because implants have few metabolic or hematologic effects. Long-term use has not been associated with a decrease in BMD and generally leads to increased blood levels and iron stores. Women who wish to space their pregnancies appreciate the nearly immediate onset of action with insertion and the rapid termination of all effects with removal. All types of implants lead to menstrual changes and other side effects in some women. Adverse effects that occur in implant users more than the general population include headaches and acne. Women must be thoroughly counseled regarding the potential for menstrual alteration, side effects, and sexually transmitted infections if they do not use condoms. Despite their initial high cost, implants are a cost-effective method over several years, even when discontinued before the life of the implant.

Use of a single implant of elcometrine (ST-1435), a nonorally active progestin, as a long acting contraceptive for postpartum nursing women

Because of its unique features, the contraceptive effectiveness and tolerance during breast-feeding of 16-methylene-17 alpha-acetoxy-19-nor-4-pregnene-3,20-dione (elcometrine), delivered within a single subdermal capsule of medical grade polydimethylsiloxane, was investigated. Unlike other progestational steroids, elcometrine has no affinity for androgen and estrogen receptors and is inactive by the oral route. A total of 66 breast-feeding women receiving elcometrine by the subdermal route were enrolled in the study, and 69 women who elected to use Copper-T380 intrauterine devices (IUD) served as control subjects. The women and their infants were observed until the end of the first postpartum year. There were no significant differences in growth and development measurements among the infants in the elcometrine and control groups. The percentage of infants continuing to breast-feed at 3 and 6 months was significantly higher in the elcometrine group. There were no significant differences between the concentration of elcometrine in the mother's blood and milk. At 75 days, blood levels of elcometrine in the infants were near the undetectable and were significantly lower than the levels in maternal blood or milk (p < 0.01). In 15 of 25 infants, blood levels of elcometrine were at the limit of assay sensitivity or undetectable. Two pregnancies occurred in women using IUD, whereas none occurred in those using implants. There were menstrual bleeding irregularities in both groups. A single elcometrine capsule placed subcutaneously at 6-monthly intervals appears to be an effective method of contraception for lactating women and results in blood concentrations of nursing infants at or near undetectable levels.

Post-partum contraception

The choice of a post-partum contraceptive method depends on many factors, including the need for a temporary versus a permanent method, the infant feeding choice and the extent to which informed consent is made prior to delivery. For maximum protection, the non-breast-feeding woman should be protected from the fourth week post-partum, even if that means using a temporary method, such as condoms or spermicides, until her method of choice is procured. Combined oestrogen/progestin methods should be avoided by all women for 2-3 weeks to avoid elevating the risk of thromboembolism. Preparations containing oestrogen should be avoided altogether during lactation because they have been associated with a reduction in milk production. POPs, implants and injectables are appropriate regardless of infant feeding choice. They can be administered immediately post-partum in bottle-feeding women, but should ideally be postponed for 6 weeks in breast-feeding women. It is best to insert IUDs within 10 minutes of delivery of the placenta, in order to minimize the risk of IUD expulsion. Insertion immediately after expulsion of the placenta requires special training, and expulsion rates are reduced with the insertion experience of the practitioner. Breast-feeding is not associated with an increase in IUD expulsion or uterine perforation, and it is associated with fewer removals for bleeding or pain. Tubal sterilization is safe, convenient and cost-effective when performed immediately after delivery, but it requires extensive counselling and fully informed consent prior to the onset of labour to avoid potential regret over post-partum tubal ligation. If the procedure is performed immediately, any effect on the establishment of lactation may be minimized. LAM is a method that can only be used by breast-feeding women. It may prove to be a useful way to time the commencement of a second, less temporary contraceptive method. Natural family planning methods require a period of abstinence for the establishment and identification of the new symptoms of fertility. When LAM is used during this interval, the need for abstinence may be reduced significantly for breast-feeding women. Breast-feeding provides health benefits for the woman and her infant, as well as the best possible nutrition for the baby. The International Planned Parenthood Federation (1990) (among others) recommends that, 'As far as is practicable, all women should be advised and encouraged to breastfeed fully'. The infant feeding decision affects the choice of a contraceptive method, and this is an important reason for the woman's physician to be interested in her infant feeding choice.

Contraception with progestogens and progesterone during lactation

The growth and development of breastfed infants whose mothers used the contraceptive implants Norplant containing levonorgestrel and the injectable containing norethisterone enanthate were studied. Each group comprised of 120 women who initiated the use during the 5th to 7th week postpartum and were compared with a similar number of IUD using mothers. The breastfeeding performance did not differ between groups. The infants of the three groups performed similarly as regards their physical growth and health as well as the time of acquisition of the various milestones of psychomental development. A vaginal ring releasing 10 mg of the "natural" progesterone per 24 h was tested in breastfeeding mothers. The continuous use of the ring produced a serum level of progesterone around 4 ng/ml. This was effective in augmenting lactational infertility even through the later phases of breastfeeding when such an effect starts to wane off. The use of the ring proved to be acceptable and had no ill-effect on breastfeeding or infant growth or health. Using the natural progesterone as a contraceptive adds a new measure of safety, since the amount of the steroid secreted in the mother's milk will not be effectively absorbed from the infant's gut. These studies suggest the possibility of using two new methods for breastfeeding mothers; Norplant and the progesterone vaginal contraceptive ring. These can be initiated early postpartum, whenever this is considered needed.

The effects of a progestin-only oral contraceptive (levonorgestrel 0.03 mg) on breast-feeding

This study was a non-randomized clinical trial which compared the breast-feeding experience of 250 Argentine women taking levonorgestrel 0.03 mg daily (begun one week after delivery) with that of 250 women using non-hormonal contraceptives. Weight gain of unsupplemented infants, the most important of the several criteria used to assess breast-feeding performance, was similar for the two contraceptive groups. Levonorgestrel users began supplementary feeding of their infants significantly later than did non-hormonal users; levonorgestrel users were also somewhat less likely to discontinue breast-feeding during the study period. The two contraceptive groups were similar with regard to several other measures of breast-feeding performance: growth of all infants (regardless of supplementation), patterns of contraceptive discontinuation, mothers' subjective impressions of breast-milk sufficiency, and comparison of supplementation initiation with previous experience.