Low-dose oral contraceptive effects on thromboelastogram criteria and relationship to hypercoagulability.
OBJECTIVE
The study was undertaken to assess hypercoagulability, by using thromboelastography, in women who use low-dose oral contraceptives (OCs).


METHODS
Forty-three women using low-dose OCs (<or=35 microg ethinyl estradiol) underwent thromboelastography before starting OCs and again during the third month of OC use. Prior and 3-month mean values of four thromboelastogram parameters (maximum amplitude [MA], K time, alpha angle, and R time) were compared by using paired t tests. Comparison according to progestin type was also performed with unpaired t tests.


RESULTS
Prior versus 3-month values for MA, alpha, and K were not significantly different (P values-K: 0.8; alpha:.34; MA: 0.49); power was adequate to detect small differences. The 3-month R time was decreased compared with pre-OC values (P =.025), although the magnitude of this change was not characteristic of hypercoagulability. Comparison according to progestin type demonstrated no difference.


CONCLUSIONS
We found no significant trend toward hypercoagulability in women who used low-dose OCs and who otherwise had no known thromboembolic risks.
Zahn
Christopher M
CM
Departments of Obstetrics and Gynecology, Wilford Hall Air Force and Brooke Army Medical Centers, USA.
Gonzalez
Dagoberto I
DI
Suto
Cathleen
C
Kennedy
Sara
S
Hines
Jeffrey F
JF
D000293:Adolescent; D000328:Adult; D001777:Blood Coagulation / Q000187:drug effects*; D003276:Contraceptives, Oral / Q000009:adverse effects* / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D005260:Female; D006801:Humans; D008875:Middle Aged; D010349:Patient Compliance; D011372:Progestins / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D013916:Thrombelastography; D019851:Thrombophilia / Q000139:chemically induced*; D013997:Time Factors
D003276:Contraceptives, Oral; D011372:Progestins; D004997:Ethinyl Estradiol