The risk of venous thromboembolism in users of postcoital contraceptive pills - PubMed

The risk of venous thromboembolism in users of postcoital contraceptive pills

C Vasilakis et al. Contraception. 1999 Feb.

Free article

Abstract

Postcoital contraceptive pills (PCP) have recently been approved for use as emergency contraception in the United States. The objective of this study was to assess the risk of idiopathic venous thromboembolism (VTE) in relation to exposure to PCP, and to better quantify the risk of idiopathic VTE associated with current oral contraceptive (OC) use and pregnancy. A population-based cohort study with a nested case-control analysis was conducted using women from the General Practice Research Database. There were no women with an outcome of idiopathic VTE with current exposure to PCP. The incidence rates for various exposures were 3.0/100,000 person-years for the unexposed, 5.3/100,000 person-years for second generation OC, 10.7/100,000 person-years for third generation OC, and 15.5/100,000 person-years in pregnant (or postpartum) women. The relative risk estimates were 1.7 (95% CI 0.3-10.5) for second generation OC, 4.4 (95% CI 1.0-18.7) for third generation OC, and 6.3 (95% CI 1.2-33.5) for pregnancy. Short-term use of PCP is not associated with a substantially increased risk for developing VTE.

PIP: A population-based cohort study with a nested case-control analysis was conducted to assess the risk of idiopathic venous thromboembolism (VTE) in relation to exposure to postcoital contraceptive pills (PCP) and to better quantify the risk of idiopathic VTE associated with current oral contraceptive (OC) use and pregnancy. The subjects were women less than 50 years of age who received PCP prescriptions at some time between January 1, 1989, and October 31, 1996. All subjects in the cohort of PCP users had a computer-recorded diagnosis from the General Practice Research Database. The results of the study indicate that there were no women currently exposed to PCP who had an outcome of idiopathic VTE. The incidence rates for various exposures were 3.0/100,000 person-years for those unexposed, 5.3/100,000 person-years for second-generation OCs, 10.7/100,000 person-years for third-generation OCs, and 15.5/100,000 person-years for pregnant (or postpartum) women. The relative risk estimates were 1.7 (95% CI, 0.3-10.5) for second-generation OCs and 4.4 (95% CI, 1.2-33.5) for pregnancy. Thus, the risk of VTE attributable to PCP is not substantially higher than it is for the risk for traditional OCs, despite the higher content of both estrogen and progesterone present in PCP.

Similar articles

• Population-based study of risk of venous thromboembolism associated with various oral contraceptives.

  Farmer RD, Lawrenson RA, Thompson CR, Kennedy JG, Hambleton IR. Farmer RD, et al. Lancet. 1997 Jan 11;349(9045):83-8. doi: 10.1016/s0140-6736(96)07496-x. Lancet. 1997. PMID: 8996419

• Risk of idiopathic cardiovascular death and nonfatal venous thromboembolism in women using oral contraceptives with differing progestagen components.

  Jick H, Jick SS, Gurewich V, Myers MW, Vasilakis C. Jick H, et al. Lancet. 1995 Dec 16;346(8990):1589-93. doi: 10.1016/s0140-6736(95)91928-7. Lancet. 1995. PMID: 7500750

• The risks of venous thromboembolic disease among German women using oral contraceptives: a database study.

  Farmer RD, Todd JC, Lewis MA, MacRae KD, Williams TJ. Farmer RD, et al. Contraception. 1998 Feb;57(2):67-70. doi: 10.1016/s0010-7824(98)00002-x. Contraception. 1998. PMID: 9589831

• Thrombotic diseases in young women and the influence of oral contraceptives.

  Lidegaard O. Lidegaard O. Am J Obstet Gynecol. 1998 Sep;179(3 Pt 2):S62-7. doi: 10.1053/ob.1998.v179.a91674. Am J Obstet Gynecol. 1998. PMID: 9753312 Review.

• The 1995 pill scare revisited: anatomy of a non-epidemic.

  Spitzer WO. Spitzer WO. Hum Reprod. 1997 Nov;12(11):2347-57. doi: 10.1093/humrep/12.11.2347. Hum Reprod. 1997. PMID: 9436662 Review.

Cited by

• How safe is emergency contraception?

  Norris Turner A, Ellertson C. Norris Turner A, et al. Drug Saf. 2002;25(10):695-706. doi: 10.2165/00002018-200225100-00002. Drug Saf. 2002. PMID: 12167065

• Cardiovascular events associated with different combined oral contraceptives: a review of current data.

  Hannaford P. Hannaford P. Drug Saf. 2000 May;22(5):361-71. doi: 10.2165/00002018-200022050-00004. Drug Saf. 2000. PMID: 10830253 Review.

• Improving teenagers' knowledge of emergency contraception: cluster randomised controlled trial of a teacher led intervention.

  Graham A, Moore L, Sharp D, Diamond I. Graham A, et al. BMJ. 2002 May 18;324(7347):1179. doi: 10.1136/bmj.324.7347.1179. BMJ. 2002. PMID: 12016180 Free PMC article. Clinical Trial.

• Third generation oral contraceptives and risk of venous thrombosis: meta-analysis.

  Kemmeren JM, Algra A, Grobbee DE. Kemmeren JM, et al. BMJ. 2001 Jul 21;323(7305):131-4. doi: 10.1136/bmj.323.7305.131. BMJ. 2001. PMID: 11463678 Free PMC article.

• Effects of making emergency contraception available without a physician's prescription: a population-based study.

  Soon JA, Levine M, Osmond BL, Ensom MH, Fielding DW. Soon JA, et al. CMAJ. 2005 Mar 29;172(7):878-83. doi: 10.1503/cmaj.045019. CMAJ. 2005. PMID: 15795408 Free PMC article.

Publication types

MeSH terms

Substances

LinkOut - more resources

• Full Text Sources

  • Elsevier Science

• Medical

  • MedlinePlus Health Information