New concepts in contraception: Norplant subdermal implant

Nurse Pract. 1992 Mar;17(3):85-9. doi: 10.1097/00006205-199203000-00016.

Abstract

PIP: User compliance is not a problem for the recently approved subdermal, longterm contraceptive delivery system, Norplant. It delivers 50-80 mcg of levonorgestrel/day during the 1st year and 30-35 mcg for years 2-5. The levonorgestrel is encased in 6 36 mm x 2.4 mm capsules which are placed in the upper arm in 5-10 minutes using local anesthesia. Since the implants systemically release levonorgestrel, the shock to the liver experienced in oral contraceptive (OC) users does not occur. Levonorgestrel prevents pregnancy by decreasing luteinizing hormone and follicle stimulating hormone which prevents ovulation, reducing the rate of ovum transfer in the tube, making the endometrium incompatible for implantation, and making the cervical mucus too thick and scanty for sperms to migrate if ovulation does occur. 1-year pregnancy rates for Norplant users are much lower than for women who use other contraceptives (0.6/100 users vs. 2.3/100 for OC users and 2.4/100 for IUD users). The ectopic pregnancy rate is also low (1.47/1000 Norplant users). The 1-year continuation rate is 80% compared with 50% for OC users. Fertility returns within 3 months for 50% of users and within 1 year for 80%. Because Norplant does not adversely affect lipid metabolism there is no increase in the risk of atherogenesis. Menstrual irregularities are the leading side effect of Norplant. The irregular cycles tend to occur during the 1st 3-6 months after insertion. Other side effects include headaches, acne, breast discharge, weight gain, and transient ovarian cysts. Contraindications are abnormal uterine bleeding, possible pregnancy, active liver disease, and women taking phenytoin. The cost for the initial exam and insertion of the Norplant capsules is $500 at Planned parenthood of the Rocky Mountains in Colorado (mean=$8.30/month vs. $13/month for 5 years of taking OCs). Due to the possibility of exploitation of women and involuntary infertility, nurse practitioners must thoroughly explain the system to each patient and answer all questions so the patient can give informed consent.

MeSH terms

  • Clinical Trials as Topic
  • Contraception / methods
  • Contraception / standards
  • Drug Implants
  • Drug Interactions
  • Female
  • Humans
  • Levonorgestrel / adverse effects
  • Levonorgestrel / pharmacokinetics
  • Levonorgestrel / therapeutic use*

Substances

  • Drug Implants
  • Levonorgestrel