title: A 10-year follow-up study of contraceptive Norplant implants.
abstract: OBJECTIVE
  To evaluate the long-term efficacy and health problems associated with Norplant implants and re-implants after 5 full years of first implants.
  
  
  METHODS
  From 1984 to 1988, 1657 women accepted first implants of Type I and Type II of Norplant, and 394 first acceptors had a re-implant, at a clinic for study. The clinical records and annual follow-up data of acceptors were analyzed. The life-table technique was the main method used.
  
  
  RESULTS
  The continuation rates were very high. The cumulative pregnancy rates at 1, 3 and 5 full years of use were 0.0%, 0.1% and 0.7%, respectively. Users with heavier body weight had higher pregnancy rates. The rate of menstrual disturbances peaked at 73% after 3 months and consistently decreased to 20% at 5 years of use. Rates of menstrual disturbances associated with re-implants were much lower.
  
  
  CONCLUSIONS
  Norplant is extremely effective and safe for long-term use.
authors.affiliation: Obstetric and Gynecology Hospital, Shanghai Medical University, Shanghai City, China.
authors.forename: M K
authors.initials: MK
authors.lastname: Du
authors.forename: L P
authors.initials: LP
authors.lastname: Chow
authors.forename: H M
authors.initials: HM
authors.lastname: Zheng
authors.forename: C H
authors.initials: CH
authors.lastname: Chen
mesh_terms: D000328:Adult; D001835:Body Weight; D003271:Contraceptive Agents, Female / Q000009:adverse effects; D020878:Device Removal; D004343:Drug Implants; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016912:Levonorgestrel / Q000009:adverse effects; D008599:Menstruation Disturbances / Q000209:etiology
chemical_list: D003271:Contraceptive Agents, Female; D004343:Drug Implants; D016912:Levonorgestrel