Norplant implants deserve a second look

Robert A. Hatcher, MD, MPH

Professor of Gynecology and Obstetrics

Emory University School of Medicine

Atlanta

At the November meeting of the Washington, DC-based American Public Health Association, data were presented from Colorado, Georgia and North Carolina, and New York suggesting that Norplant deserves a close second look. I came away concluding that when thinking about the prevention of unintended pregnancies in teen-agers, one simply cannot compare Norplant to combined oral contraceptives in the same breath.

Data presented by Helen Koo, DrPH, senior research demographer of the Research Triangle Institute in Research Triangle Park, NC, described event rates for 2,477 women provided contraceptives at Grady Memorial Hospital in Atlanta and at several clinics in Charlotte, NC.1 At the end of 12 months, the discontinuation rate for Norplant in teen-agers under 18 was 11%, while it was 12% for women 19 or older. Among younger women using Depo-Provera in the same clinics, a discontinuation rate of 38% was reported, while the discontinuation rate was 47% for women 19 or older. Even more discouraging are the discontinuation rates for women choosing pills. Women under 18 had a 12-month discontinuation rate of 71% at 12 months and 81% at 18 months; older women had a 12-month discontinuation rate of 55% and an 18-month discontinuation rate of 66%.

Koo also presented adjusted cumulative rates of unintended pregnancy, which were 7% for women 18 or younger on pills and 2% for women 19 or older. Rates of unintended pregnancy while using Norplant and Depo-Provera were too low (0 to 2%) to estimate full models (adjusted cumulative rates of unintended pregnancy.) Pregnancy rates do not include pregnancies after a method is discontinued. These data are being analyzed.

Margaret Polaneczky, MD, medical director of women’s health at New York Hospital-Cornell Medical Center in New York City found a 12-month continuation rate among 261 users of Depo-Provera of 42% (mean age 25.2).2 Depo-medroxyprogesterone (DMPA) continuation rates did not vary by age or marital status. There were no pregnancies in women continuing DMPA. However, this study, as was the case in the data presented by Koo, did not look at pregnancies following discontinuation of DMPA.

Data presented by Barbara Dalberth, associate biostatistician at Family Health International in Research Triangle Park, NC, found DMPA 12-month continuation rates of only 27% to 47%, depending on what assumptions were made about what happened to women lost to follow-up.3 Bleeding problems were important causes of discontinuation in the New York women described by Polaneczky and the North Carolina women described by Dalberth.

Finally, data presented by Sue Austin Ricketts, PhD, a demographer with the Denver-based Colorado Department of Health and Environment, demonstrated a low rate of repeat pregnancy among teen-agers in the 24 months following delivery in the two years after Norplant implants became available in Colorado.4 As the data reflect, (see the cover story) the probability of repeat births dropped dramatically once the implant was made available to mothers covered under the state Medicaid program.

Data from Atlanta and Charlotte, NC, suggest far higher rates of continuation and lower rates of pregnancy in young teen-agers and in older women using Norplant than for women in the same age groups using pills or Depo-Provera.

Certainly, one has to counsel women to expect extensive menstrual irregularity if one hopes to have excellent rates of continuation of Norplant implants. But if there is good counseling and attention to the concerns of women using this method, continuation rates and levels of satisfaction are high, while failure rates are very low. Norplant deserves a second look. It is a remarkably effective method of birth control.

References

1. Koo HP, Griffith JD, Nennstiel M. Adolescents’ use of Norplant and Depo-Provera: How do they do? Poster session at the November 1996 meeting of the American Public Health Association, New York City.

2. Polaneczky M, Guarnaccia M, Alon J, et al. Early experience with the contraceptive use of depo-medroxyprogesterone acetate in an inner-city population. Fam Plann Perspect 1996; 28:174-178.

3. Dalberth B, Potter L, Canamer R. Evaluating Depo-Provera continuation at a health department clinic. Poster session at the November 1996 meeting of the American Public Health Association, New York City.

4. Ricketts SA. Repeat fertility and the impact of the contraceptive implant among Medicaid mothers in Colorado. Poster session at the November 1996 session of the American Public Health Association, New York City.