Evidence-Based Medicine for Student Health Services
Robert J. Flaherty, MD
Swingle Student Health Service
Montana State University
Bozeman, MT 59717

Contraception
 

Etiology	Monitoring
Epidemiology	Prognosis
Diagnosis	Prevention
Treatment	Patient Education

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Etiology  No evidence is cited.     Epidemiology  No evidence is cited.     Diagnosis  Clinical Diagnosis Evidence suggests that historical features are not reliable for ruling out pregnancy. To establish a diagnosis of early pregnancy, a clinician should order a urine or serum HCG test. Caveats Age group studied: Women of childbearing age Type/size: Meta-analysis (9 studies) Population characteristics: Unclear Outcome measure: Serum or urine HCG result or pregnancy outcome Citations Is this patient pregnant? - Reviewed by DARE  Laboratory/X-ray Diagnosis No evidence is cited.      Treatment  In General Failure rates of contraceptives include cervical cap (30%), diaphragm (18%), male condom (12%), injectable contraception (0.3%), combined oral contraceptive (0.08% - this is less than for tubal ligation=0.17%). Over five years the copper-T IUD, vasectomy, contraceptive implant and injectable contraceptive are the most cost-effective options. Caveats Age group studied: Women of childbearing age Type/size: Unknown Population characteristics: Unknown Outcome measure: Pregnancy Citations Contraception-some numbers - Reviewed by Bandolier  Oral Contraceptives  Studies of the combined oral contraceptive of 30µg ethinyloestradiol and 150µg desogestrel (e.g. Desogen) show, on average,  low rates of side effects. Caveats Age group studied: Women of childbearing age Type/size: Review of trials (>10,000 patients) Population characteristics: Unknown Outcome measure: Pregnancy Citations Contraception-some numbers - Reviewed by Bandolier  Women taking oral contraceptives and long term antibiotics had a small but statistically insignificant increased risk of pregnancy. Overall OC failure rates were no higher than expected for OC users. Caveats Age group studied: Young women Type/size: Retrospective cohort study of 356 Population characteristics: Patients in a dermatology clinic on long-term (>3 mo) antibiotics Outcome measure: Pregnancy Citations OCP failure and oral antibiotics: Review of Helms SE et al, Oral contraceptive failure rates and oral antibiotics. J Am Acad Dermatol 1997;36:705-10s - Reviewed by POEMS/JFP   Similarly: "Most of the available data do not indicate any major reduction in the efficacy of OCPs with concurrent common antibiotic use." Burroughs KE et al, Antibiotics and oral contraceptive failure, JAMA 2000 Jan, 9: 81-82   The vast majority of women who take low-dose oral contraceptive pills (OCPs) can feel secure that they are at little or no increased risk for stroke. Women over the age of 35 who smoke must continue to avoid OCPs. Caveats Age group studied: 15-44y Type/size: Retrospective population study of 1.1 million = 3.6 million women-years Population characteristics: Enrollees in an HMO taking OCPs Outcome measures: Relative risk of hemorrhagic or ischemic stroke, as estimated by the odds ratio Citations Stroke and OCP use: Review of Petitti DB et al, Stroke in users of low-dose oral contraceptives. New Engl J Med 1996;335:8-15 - Reviewed by POEMS/JFP    Norplant   Norplant use was associated with fewer reported pregnancies than OC and condom use. Although implant use was frequently associated with side effects, continuation rates were high. Caveats Age group studied: Adolescents Type/size: 166 Population characteristics: Patients at an inner-city comprehensive adolescent clinic and teen mother and baby clinic Outcome measures: Satisfaction and side effects Citations Norplant vs OCPs or other methods in adolescents: Review of Dinerman LM et al,  Outcomes Of Adolescents Using Levonorgestrel Implants Vs. Oral Contraceptives Or Other Contraceptive Methods. Arch Ped Adol Med 1995;149: 967-972 - Reviewed by POEMS/JFP   Users of oral contraceptives were more satisfied than Norplant users with their choice of contraception. In contrast, Norplant users were more likely to continue use, possibly due to the effort required to remove the device.  Caveats Age group studied: < 40y Type/size: Unclear Population characteristics: Patients at an inner-city comprehensive adolescent clinic and teen mother and baby clinic Outcome measures: Satisfaction and side effects Selection and recall bias may be responsible for these findings Citations Women's satisfaction with Norplant: Review of Eilers GM et al, Women's satisfaction with Norplant compared to oral contraceptives. J Fam Pract 1994; 38:596-600 - Reviewed by POEMS/JFP  Depo-Provera Depo-Provera is well-tolerated, convenient and effective, especially for adolescents.  Caveats Not EBM, but a good review Citations Kaunitz AM, Injectable depot medroxyprogesterone acetate contraception: an update for U.S. clinicians, Int J Fertil Womens Med 1998 Mar;43(2):73-83 - From PubMed     Monitoring No evidence is cited.   Prognosis   No evidence is cited.      Prevention  No evidence is cited.     Patient Education The following patient education materials are consistent with the available evidence. Depo-Provera - An Injectable Contraceptive - From the AAFP Sexuality, STDs and Contraception - From the MSU Student Health Service    Rev. 8/1/00

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