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"Morning-after pill" and antithrombin III
Acta Obstetricia Et Gynecologica Scandinavica
|January 1, 1983
Summary
The morning-after pill significantly reduced plasma antithrombin III levels by 17% in patients. This decrease is attributed to fluid retention (hemodilution), not changes in AT III production or usage.
Area of Science:
- Pharmacology
- Hematology
- Endocrinology
Background:
- Plasma antithrombin III (AT III) is a critical anticoagulant protein.
- Hormonal contraceptives can influence coagulation factors.
- The effect of emergency contraception on AT III requires further investigation.
Purpose of the Study:
- To longitudinally assess changes in plasma antithrombin III levels in individuals using the morning-after pill.
- To elucidate the mechanism behind any observed alterations in AT III levels.
Main Methods:
- Longitudinal study involving 15 subjects (13 patients, 2 volunteers).
- Administration of 5 mg ethinylestradiol daily for 5 days (morning-after pill).
- Measurement of plasma antithrombin III levels before and after treatment.
Main Results:
- A mean decrease of 17% in plasma AT III levels was observed in patients.
- Additional observations suggested the decrease was linked to hemodilution.
- No evidence indicated decreased AT III synthesis or increased consumption.
Conclusions:
- Emergency hormonal contraception with ethinylestradiol can lead to a reduction in plasma antithrombin III.
- Hemodilution secondary to salt and water retention is the likely cause of decreased AT III levels.
- This suggests a need for careful consideration of thrombotic risk in users.
Keywords:
BiologyBlood Coagulation Effects--analysisContraceptionContraceptive AgentsContraceptive Agents, EstrogenContraceptive Agents, FemaleContraceptive Agents, PostcoitalEthinyl EstradiolFamily PlanningFertility Control, PostcoitalHematological EffectsHemic SystemLongitudinal StudiesPhysiologyResearch MethodologySampling StudiesStudiesSurveys