Comparative studies of 30 fJ-g ethinyl estradiol combined with gestodene and desogestrel on blood coagulation, fibrinolysis, and platelets Leisha Daly and John Bonnar, MD, FRCOG Dublin, Ireland An association between an increase in the incidence of thromboembolic disease and the use of combined oral contraceptives has been shown by several epidemiologic studies. Evidence of the vascular complications of oral contraceptives suggests that venous thromboembolism correlates with estrogen dosage and arterial complications with both estrogen and progestogen components. In 60 healthy, randomly allocated women, the effects of ethinyl estradiol, 30 II-g, combined with gestodene, 75 II-g, and desogestrel, 150 II-g, on blood coagulation, fibrinolysis, and platelet function were compared. Subjects were studied before oral contraceptive use, at 12, 24, 36, and 48 weeks of treatment, and at 6 and 12 weeks after treatment. Both oral contraceptives affected the hemostatic system, but our results indicate that the ethinyl estradiol/gestodene combination causes changes in the hemostatic system similar to those in the ethinyl estradiol/desogestrel combination. Factors VII and X activity were slightly higher with the ethinyl estradiol/desogestrel combination than with the ethinyl estradiol/gestodene combination, possibly reflecting a greater estrogenic effect. (AM J OBSTET GYNECOL 1990;163:430-7.)
Key words: Oral contraceptives, coagulation, fibrinolysis, dosage of estrogen, type of progestogen
Since the introduction of oral contraceptives in the early 1960s, several epidemiologic studies have reported an association between their use and an increased risk of vascular disease. The main vascular complications are venous thromboembolic disease, myocardial infarction, and hemorrhagic and thrombotic strokes. I.5 This risk appears to have decreased in parallel with a reduction in the estrogen content. 6 •B The progestogen component of the pill modifies the estrogen effects on blood coagulation9.10 and may contribute to the increased risk of stroke and ischemic heart disease. IO.I2 New formulations of oral contraceptives have recently been introduced containing low doses of estrogen in combination with new progestogens. This study is designed to examine the effects of two new combined oral contraceptives on blood coagulation, fibrinolysis, and platelet function. These pills contain 30 I-Lg of ethinyl estradiol, in combination with gestodene or desogestrel, in monophasic formulations.
Material and methods Subjects. Sixty healthy women who were between the ages of 18 and 34 years with no contraindications to estrogen/progestogen therapy took part in the study. From the Trinity College Department of Obstetrics and Gynaecology, University of Dublin, and Sir Patrick Dun Research Laboratory, St. James's Hospital. Reprint requests: Prof J. Bonnar, Coagulation Laboratory, SPD Research Centre, St. James's Hospital, Dublin 8, Ireland. 610117865
430
Women who smoked 15 cigarettes or more per day were excluded. Subjects were randomly allocated to two groups: (1) group I: 30 women taking Femodene, containing 30 I-Lg of ethinyl estradiol + 75 I-Lg of gestodene, 21 tablets per cycle, and (2) group 2: 30 women taking Marvelon, containing 30 I-Lg of ethinyl estradiol + ISO I-Lg of desogestrel, 21 tablets per cycle. Method and timing of blood collection. Venous blood specimens were taken between 10:00 AM and noon each morning in the control cycle and thereafter at 12, 24, 36, and 48 weeks of treatment and at 6 and 12 weeks after hormone treatment. In the pretreatment cycle, blood samples were taken between days 21 and 24 of the cycle. In the treatment cycles blood samples were taken between days IS and 21 of tablet administration. Laboratory methodology. Prothrombin time,I3 activated thromboplastin time,I4 factor VII activity,I5 and fibrinogen I6 were assayed by standard laboratory techniques. Specific chromogenic substrates were used to assay plasminogen,17 antithrombin 111,18 factor X,I9, anti-Xa,2° and antiplasmin. 21 Plasminogen activator was measured by means of the euglobulin precipitate and the fibrin plate technique!2 The Chandler tube method 23 was used to measure thrombin-induced platelet aggregation, and platelets were counted with a Thrombocounter-C!4 Prothrombin clotting time, factor VII, activated thromboplastin time, platelet aggregation, platelet count, and fibrin plate assay were car-
Hemostatic effects of oral contraceptives
Volume 163 Number I, Part 2
ried out within 1 hour of venipuncture. Factor X, anti-Xa, antiplasmin, plasminogen, antithrombin III, and fibrinogen were assayed on fresh-frozen plasma stored at - 20° C. Statistical analysis. The null hypothesis was that both oral contraceptives were equal with respect to the hemostatic parameters that were measured. The alternative hypothesis was that with a sample size of 30 women in each treatment group, a type I error of a = 0.05, and a test power of 1 - ~ = 0.90, a t test would detect a difference of ~ = 0.8* (J. The maximal increase or minimal decrease in the treatment phase was analyzed with an analysis of covariance (covariate = prevalue of the appropriate variable, dependent variable = maximal increase or minimal decrease at a = 0,05), Similarly, the values of 12 weeks after treatment were analyzed with an analysis of covariance with the prevalues as covariate at a = 0,05, Descriptive statistics (average, minimum, maximum, percentage averages, and box plots) (Fig, 1) were computed for all variables, Student t tests were used to determine the level of significance of the observed changes within the groups,
431
Explanation of the box-plots case reports: extreme values further than one box length from Q 75
o
2
75 Ofo quartile + 1 box length
maximum within 3 box lengths box length
r-'-- - -
box length the interquartile range
• r--~r-
75 % quartile
mean value 50% quartile = median
---
25 % quartile
___
minimum within 3 box lengths
box length
Results Coagulation system Prothrombin time. There was no observable difference between treatments in the treatment and posttreatment phases (p > 0,05). The maximal increase has a positive slope ~ = 0,05; Fig, 2 shows a stable progression of the average time curve. Activated partial thromboplastin time, There were no observable differences between treatments in the treatment and posttreatment phases (p > 0,05), The maximal increase over the treatment phase has a negative slope ~ = - 0, 17; Fig, 3 shows a slight decrease in the average time curve. Factor VII, Factor VII dotting time was decreased at 12, 24, 36, and 48 weeks in women taking either the desogestrel or the gestodene combination, which indicated an increase in factor VII activity (p < 0,001); the decrease was slightly greater in those women taking the desogestrel combination. There was no observable difference between treatments in the treatment and posttreatment phases (p> 0,05). The maximal increase over the treatment phase has a positive slope ~ = 0.34 (p < 0.05), but Fig. 4 shows a decrease in the average time curve. Factor X. Factor X was increased at 12, 24, 36, and 48 weeks of treatment when compared with pretreatment levels in both groups (p < 0.001); the increase was slightly greater in the desogestrel group, Factor X activity 6 weeks after treatment was decreased from that at 48 weeks while receiving treatment. There was no observable difference between treatments in the treatment phase (p> 0.05), but 12 weeks after treatment
'" 25 % quartile - 1 box length
o
case reports: extreme values at least one box length below Q 25
Fig. l. Description of box plots.
there was a difference between the two treatment groups (p < 0.05). The level of factor X for the desogestrel group was higher than that for the gestodene group. The maximal increase over the treatment phase has a positive slope ~ = 0.14; Fig. 5 shows a slight increase in the average time curve. Antithrombin Ill. Antithrombin III levels were decreased at 36 weeks in women taking either combination (p < 0.01). At 6 weeks after treatment, the antithrombin III levels of both groups had returned to within the normal range. There were no observable differences in antithrombin III levels between treatments in the treatment and posttreatment phases (p> 0.05). The minimal decrease over the treatment phase has a positive slope ~ = 0.38; Fig. 6 shows a stable progression of the average time curve. Anti-Xa. There was no observable difference between treatments in the treatment and posttreatment phases (p> 0.05). The minimum decrease over the treatment phase has a negative slope ~ = - 0.11; Fig, 7 shows a slight decrease in the average time curve, Fibrinolytic system Plasminogen, Plasminogen levels at 12, 24, 36, and 48
432
Daly and Bonnar
July 1990 Am.J Obstet Gynecol
Gestodene left I Desogestrel right monophasIC gestocIene , alhlny\e8lradlol (FEMOOENE) monophasIC de8oge8treI , ethlnyle&lradlol lMARVELONI
20'" Prothrombin time
lsI
19 18 17
16
15 14
13
12 11 10~__~~__~__~~__~__.-~__~~.-~__,
12
Pre
24
36
48
6_ 12_
Weeks
Fig. 2. Effects of gestodene and desogestrel on prothrombin time.
Gestodene left I Desogestrel right
monophasIC gestocIene , alhlnyle&lradlol lFEMODENEI monophasIC desog88lnl1 , ethlnyle&lradlol lMARVELONI
60'" APTT (sl o
00
o
50
40
30~--.-~--~--.-~--~--r-~--~~r-~--. 12 24 36 48 6_ 12_ Weeks Pre
Fig. 3. Effects of gestodene and desogestrel on activated partial thromboplastin time.
Gestodene left I Desogestrel right monophasIC gestocIene , alhlnyle&lradlol (FEMODENE) monophasIC de8oge8treI , ethlnyIe&Iradlol lMARVB.ONI
20'" Factor VII
18
0
0
16
14
~~ 0
12
(sl
0 0
10
Pre
8
0 0
l~ ~~ 12
24
0
!~ 36
~~ ~a ~8 0
0 0
48
0
6 .... 12 ....
Fig. 4. Effects of gestodene and desogestrel on factor VII.
Weeks
Hemostatic effects of oral contraceptives 433
Volume 163 Number I, Part 2
Gestodene left I Desogestrel right rnonophaaIc ~ I elhlnyleelradlol (FEMODENE) rnonophaaIc deaogestreIl elhlnyleetradlol !MARVELON}
190'" Factor X ('MI) 170
o
150
o
130 110
r
90
I
70
~
Pre
12
24
36
48
6_ 12_
WeekS
Fig. 5. Effects of gestodene and desogestrel on factor X,
Gestodene left I Desogestrel right rnonophaaIc ~ I elhlnyleetradlol (FEMODEHEl rnonophaaIc deaogestreIl ethInyIMndIoI (MARVa0N)
170'" AntIthrombin III ('MI)
150 130
110 90 70
o
o
~ ~
f i~ ~ j.s: 0
24
Pre
36
48
6_ 12_
Weeks
Fig. 6. Effects of gestodene and desogestrel on antithrombin III.
Gestodene left I Desogestrel right rnonophaaIc ~ I ethlnyleetradlol (FEMODEHE) monophasic d8lOg88lrel1 ethlnylestradtol (MARVaON)
200'" AntI Xa ('MI) 0
180 160 140 120 100
80
60
~ .j 0
Pre
·0
12
0 0
.~ ~~ 24
~~ l~ ~~ 0
o
00
0
36
Fig. 7. Effects of gestodene and desogestrel on anti-Xa.
434
Daly and Bonnar
July 1990 Am J Obstet Gynecol
Gestodene left I Desogestrel right monophaaIc gestodene / elhtnyle8lradlol (FEM()OENE) monophaaIc ~ / 8\111n)1esIrad1ol (MARVELON)
200'" Plasminogen
(%) 0
8@
175 150
125 100
75
~ ~ 0
0
8
50
12
Pre
~ ~~
o o
0
24
36
48
6_ 12_
Weeks
Fig. 8. Effects of gestodene and desogestrel on plasminogen.
Gestodene left I Desogestrel right monophaaIc gestodene / ethl~ (FEMODENE) monophaaIc deeogesIreI/ ~101 (MARVELON)
170'" Antiplasmln (%) 150 130
no 90 70
0
9
0
~~~ ~I ~~ ~ ~
~ o~ 1
!
0
0
50 Pre
12
24
0
00
36
48
0
9
6_ 12_
Weeks
Fig. 9. Effects of gestodene and desogestrel on anti plasmin.
weeks were increased by both pills (p < 0.001). There was a difference between treatments in the treatment phase (p < 0.05), and there was no difference between treatments 12 weeks after treatment (p> 0.05). The plasminogen level was higher in the gestodene group than in the desogestrel group. The maximal increase over the treatment phase has a positive slope ~ = 0.08; Fig. 8 shows a slight increase in the average time curve. Antiplasmin. There was no observable difference between treatments in the treatment phase (P > 0.05), but there was a difference between the two treatment groups 12 weeks after treatment (P < 0.05). The antiplasmin level was higher in the desogestrel group than in the gestodene group. The maximal increase over the treatment phase has a negative slope ~ = - 0.33; Fig. 9 shows a slight decrease in the average time curve.
Fibrinogen. Fibrinogen levels increased with both pills (P 0.05). The maximal increase over the treatment phase has a positive slope ~ = 0.24; Fig. 10 shows a slight increase in the average time curve. Fibrinolytic activity. Fibrinolytic activity increased from 12 weeks on treatment in both groups (P < 0.001). During treatment increased fibrinolytic activity was sustained and rapidly returned to pretreatment levels 6 weeks after the pill was stopped. There was no observable difference between treatments in the treatment and posttreatment phases (P > 0.05). The maximal increase over the treatment phase has a positive slope
Hemostatic effects of oral contraceptives
Volume 163 Number I, Part 2
435
Gestodene left I Desogestrel rtght monop/IaIIC geetodane / ~ (FEMODENE) monop/IaIIC de8oged'eI/ ~ (MARVELON)
500 '" Abrtnogen (mg /
wo mO
450
o
,! !~ ~~~
400 350
300 250 200
150 @
WO~--~~~-r--~--~~---r--'---r-~---r--' 12 24 36 Pre 48 6 .... 12.... Weeks
Fig. 10. Effects of gestodene and desogestrel on fibrinogen.
Gestodene left I Desogestrel rtght monop/IaIIC geetodane / 8IhInyIeaIradIoI (FEMODENE) monop/IaIIC de8oged'eI/ eIhInyIeetradIo (MARVELON)
380 '" Abltnolytk: ActMIy (mm 2 ) 0
330 0
oT
280 230
180
130
80
0
~ Pre
0 0 0
~J ~~ 0
0
12
24
!
36
00 0
••
1 48
0
§~ ~B
6 .... 12....
Weeks
Fig. 11. Effects of gestodene and desogestrel on fibrinolytic activity.
13 = 0.22; Fig. 11 shows a slight increase in the average time curve. Platelets Platelets aggregation. Platelet aggregation was decreased in both groups and the decrease was greater in the desogestrel group (p < 0.001) than in the gestodene group (p < 0.01). There was no observable difference between treatments in the treatment and posttreatment phases (p> 0.05). The minimal decrease over the treatment phase has a slope 13 = 0.20, but Fig. 12 shows a slight decrease in the average time curve. Platelet count. There was no observable difference between treatments in the treatment and posttreatment phases (p > 0.05). The maximal increase over the treatment phase has a slope 13 = 0.00; Fig. 13 shows a stable progression in the average time curve.
Comment
The new low-dose estrogen/progestogen oral contraceptives induce major changes in the coagulation and fibrinolytic systems and in platelet function. The prothrombin time and activated partial thromboplastin time, which measure the overall activity of the extrinsic and intrinsic coagulation pathways, respectively, showed no significant changes with both oral contraceptive formulations. This indicates that the overall effects of the new pills are less than what occurs with the 50 fJ.g pills that induce significant changes in these tests. 9 Likewise, changes in the coagulation system with respect to factor X, antithrombin III, and platelet aggregation are not as marked with the new low-dose monophasic oral contraceptives as with those previously studied that contained 50 fJ.g of estrogen. 10 Both estro-
436
Daly and Bonnar
July 1990 Am J Obstet Gynecol
Gestodene left I Desogestrel right monophasic gestodene 1 elhlnytestradlol (FEMODENE) monophasic deaogestreIl elhlnylestracllOl (MARVELON)
1000'" Platelet Aggregation (s)
o
650
700 550
.~ 0
400 250
0
0
0 0
Pre
8
~
0
.~ 0
0
0 0
~~ $~ ~~~~ 0
0
24
12
36
48
6"", 12"",
Weeks
Fig. 12. Effects of gestodene and desogestrel on platelet aggregation.
Gestodene left I Desogestrel right monophasic gestodene 1 elhlnylestradlol (RMODENE) monophasic de8oge8trel 1 elhlnytestradlOl (MARVELON)
550'" Platelet Count
Ix 10 3 ,
mm 3 )
0
0
470 390
310 230
~~ !~ 0
150
8
~
12
.~
1
0
n
Pre
l
0
24
36
~. ~~ ~! 0
0
48
6"", 12"",
Weeks
Fig. 13. Effects of gestodene and desogestrel on platelet count.
gen/progestogen pills increased significantly the activity or factors V II and X, and the greater increase with the desogestrel pill suggests this combination has a greater estrogenic effect. Plasminogen and fibrinolytic activity were markedly increased by both hormonal preparations, and this enhancement of fibrinolysis is likely to counteract the increase in fibrinogen and coagulation activity that protects the dynamic balance between coagulation and fibrinolysis. Platelet aggregation was decreased by both pills and more so by the desogestrel combination. This would seem to be an undesirable effect. The low-dose oral contraceptives with the new progestogens studied induce marked changes in the hemostatic system, in particular, enhanced activity of factors VII and X and acceleration of platelet aggregation.
These changes in the physiology of hemostasis suggest that these new pills will also carry a thrombogenic hazard in susceptible women. The effects on hemostasis arise from the overall estrogenic activity, which is determined by the progestogen used in combination with the estrogen. More research is required to find whether effective combinations can be obtained that will induce fewer changes in the hemostatic system and other physiologic processes. Meantime, it would be unwise for any claims to be made that oral contraceptives with the new progestogens, gestodene and desogestrel, will be free of vascular complications. We acknowledge the technical help of Lucy Norris and the detailed supervision of the women carried out by research nurses, Eilis Carroll and Bernadette Hennelly. We also thank the women who kindly agreed to
Hemostatic effects of oral contraceptives
Volume 163 Number I, Part 2
take part in this study and Dr. T. Louton of the Statistics Department, Schering AG, Berlin, who kindly carried out the analysis of covariance and prepared the box plots.
14.
15.
REFERENCES I. Wiseman RA, McRae KD. Oral contraceptives and the decline in mortality from circulatory disease. Ferril Steril 1981;35:277-83. 2. Shapiro S. Oral contraceptives-a time to take stock. N EnglJ Med 1986;315:450-1. 3. Stadel B V. Oral contraceptives and cardiovascular disease. N EnglJ Med 1981;305:612-8; 672-7. 4. Helmrich SP, Rosenberg L, Kaufman DW, Strom B, Shapiro S. Venous thromboembolism in relation to oral contraceptive use. Obstet Gynecol 1987;69:91-5. 5. Inman WHW, Vessey MP, Westerholm B, England A. Thromboembolic disease and the steroidal content of oral contraceptives. Br MedJ 1970;2:203-6. 6. Meade TW, Greenberg G, Thompson SG. Progestogens and cardiovascular reactions associated with oral contraceptives and a comparison of the safety of 50- and 30-l1g oestrogen preparations. Br Med J 1980;280: 1157-61. 7. Bottiger LE, Boman G, Elkund G, Westerholm B. Oral contraceptives and thromboembolic disease: effects of lowering oestrogen content. Lancet 1980; 1: 1097-10 I. 8. Notelovitz M, Kitchens CS, Coone L, McKenzie L, Carter R. Low-dose oral contraceptive usage and coagulation. AM J OBSTET GVNECOL 1981; 141 :71-5. 9. Meade TW. Oral contraceptives, clotting factors and thrombosis. AM J OBSTET GVNECOL 1982; 142:758-61. 10. Sabra A, Bonnar J. Haemostatic system changes induced by 50 I1g and 30 I1g oestrogen/progestogen oral contraceptives. Modification of oestrogen effects by levonorgestrel. J Reprod Med 1983(suppl);28:85-91. 11. Bonnar J, Daly L, Carroll E. Blood coagulation with a combination pill containing gestodene and ethinyl estrodiol. IntJ Fertil 1987(suppl);32:21-8. 12. Bonnar J. Coagulation effects of oral contraception. AM J OBSTET GVNECOL 1987;157:1042-8. 13. Biggs R. Prothrombin time measurement. In: Biggs R,
16. 17.
18. 19.
20. 21.
22.
23. 24.
437
ed. Human blood coagulation, haemostasis and thrombosis. Oxford: Blackwell Scientific Publications, 1972:605. ThomsonJM. Activated partial thromboplastin time measurement. In: ThomsonJM, ed. A practical guide to blood coagulation and haemostasis. London: Churchill Livingstone, 1970: 122. Poller L, Thomson JM, Sear CHJ, Thomas W. Identification of a congenital defect of factor VII in a colony of beagle dogs: the clinical use of the plasma. J Chern Pathol 1971 ;24:626-30. Clauss A. Gerinnungsphysiologische Schnellmethode zur Bestimmung des Fibrinogens. Acta Haematol 1957;17: 237-46. SoriaJ, Soria C, Samama MM. A plasminogen assay using a chromogenic synthetic substrate: results from clinical work and from studies of thrombolysis. In: Davidson JF, Rowan RM, Samama MM, Desnoyers PC, eds. Progress in chemical fibrinolysis and thrombolysis. New York: Raven Press, 1978;3:337-46. Odegard OR, Fagerhol MK, Lie M. Heparin cofactor activity measured with an amidolytic method. Thromb Res 1975;6:287. Bergstrom K, Edgberg N. Determination of vitamin K sensitive coagulation factors in plasma. Studies on three methods using synthetic chromogenic substrates. Thromb Res 1978;72:531. Odegard OR, Lie M, Abildgaard U. Antifactor Xa activity measured with amidolytic methods. Haemostasis 1976;5: 265. Teger-Nilsson AC, Friberger P, Gysander E. Determination of a new rapid plasma inhibitor in human blood by using a plasmin specific tripeptide substrate. ScandJ Clin Lab Invest 1977;37:403. Kluft C, Brakman P, Veldhuyzen-Stolk EC. Screening of fibrinolytic activity in plasma euglobulin fractions on the fibrin plate. In: Davidson JF, Sarna rna MM, Desnoyers PC, eds. Progress in chemical fibrinolysis and thrombolysis. New York: Raven Press, 1976;2:57-65. Thomson JM. The chandler's tube technique. In: ThomsonJM, ed. Practical guide to blood coagulation and haemostasis. London: Churchill Livingstone, 1970:35. Bull BS, Schneiderman MA, Brecher G. Platelet count with the Coulter counter. Am J Clin Pathol 1965;44:67888.
Key words: Oral contraceptives, coagulation, fibrinolysis, dosage of estrogen, type of progestogen
Since the introduction of oral contraceptives in the early 1960s, several epidemiologic studies have reported an association between their use and an increased risk of vascular disease. The main vascular complications are venous thromboembolic disease, myocardial infarction, and hemorrhagic and thrombotic strokes. I.5 This risk appears to have decreased in parallel with a reduction in the estrogen content. 6 •B The progestogen component of the pill modifies the estrogen effects on blood coagulation9.10 and may contribute to the increased risk of stroke and ischemic heart disease. IO.I2 New formulations of oral contraceptives have recently been introduced containing low doses of estrogen in combination with new progestogens. This study is designed to examine the effects of two new combined oral contraceptives on blood coagulation, fibrinolysis, and platelet function. These pills contain 30 I-Lg of ethinyl estradiol, in combination with gestodene or desogestrel, in monophasic formulations.
Material and methods Subjects. Sixty healthy women who were between the ages of 18 and 34 years with no contraindications to estrogen/progestogen therapy took part in the study. From the Trinity College Department of Obstetrics and Gynaecology, University of Dublin, and Sir Patrick Dun Research Laboratory, St. James's Hospital. Reprint requests: Prof J. Bonnar, Coagulation Laboratory, SPD Research Centre, St. James's Hospital, Dublin 8, Ireland. 610117865
430
Women who smoked 15 cigarettes or more per day were excluded. Subjects were randomly allocated to two groups: (1) group I: 30 women taking Femodene, containing 30 I-Lg of ethinyl estradiol + 75 I-Lg of gestodene, 21 tablets per cycle, and (2) group 2: 30 women taking Marvelon, containing 30 I-Lg of ethinyl estradiol + ISO I-Lg of desogestrel, 21 tablets per cycle. Method and timing of blood collection. Venous blood specimens were taken between 10:00 AM and noon each morning in the control cycle and thereafter at 12, 24, 36, and 48 weeks of treatment and at 6 and 12 weeks after hormone treatment. In the pretreatment cycle, blood samples were taken between days 21 and 24 of the cycle. In the treatment cycles blood samples were taken between days IS and 21 of tablet administration. Laboratory methodology. Prothrombin time,I3 activated thromboplastin time,I4 factor VII activity,I5 and fibrinogen I6 were assayed by standard laboratory techniques. Specific chromogenic substrates were used to assay plasminogen,17 antithrombin 111,18 factor X,I9, anti-Xa,2° and antiplasmin. 21 Plasminogen activator was measured by means of the euglobulin precipitate and the fibrin plate technique!2 The Chandler tube method 23 was used to measure thrombin-induced platelet aggregation, and platelets were counted with a Thrombocounter-C!4 Prothrombin clotting time, factor VII, activated thromboplastin time, platelet aggregation, platelet count, and fibrin plate assay were car-
Hemostatic effects of oral contraceptives
Volume 163 Number I, Part 2
ried out within 1 hour of venipuncture. Factor X, anti-Xa, antiplasmin, plasminogen, antithrombin III, and fibrinogen were assayed on fresh-frozen plasma stored at - 20° C. Statistical analysis. The null hypothesis was that both oral contraceptives were equal with respect to the hemostatic parameters that were measured. The alternative hypothesis was that with a sample size of 30 women in each treatment group, a type I error of a = 0.05, and a test power of 1 - ~ = 0.90, a t test would detect a difference of ~ = 0.8* (J. The maximal increase or minimal decrease in the treatment phase was analyzed with an analysis of covariance (covariate = prevalue of the appropriate variable, dependent variable = maximal increase or minimal decrease at a = 0,05), Similarly, the values of 12 weeks after treatment were analyzed with an analysis of covariance with the prevalues as covariate at a = 0,05, Descriptive statistics (average, minimum, maximum, percentage averages, and box plots) (Fig, 1) were computed for all variables, Student t tests were used to determine the level of significance of the observed changes within the groups,
431
Explanation of the box-plots case reports: extreme values further than one box length from Q 75
o
2
75 Ofo quartile + 1 box length
maximum within 3 box lengths box length
r-'-- - -
box length the interquartile range
• r--~r-
75 % quartile
mean value 50% quartile = median
---
25 % quartile
___
minimum within 3 box lengths
box length
Results Coagulation system Prothrombin time. There was no observable difference between treatments in the treatment and posttreatment phases (p > 0,05). The maximal increase has a positive slope ~ = 0,05; Fig, 2 shows a stable progression of the average time curve. Activated partial thromboplastin time, There were no observable differences between treatments in the treatment and posttreatment phases (p > 0,05), The maximal increase over the treatment phase has a negative slope ~ = - 0, 17; Fig, 3 shows a slight decrease in the average time curve. Factor VII, Factor VII dotting time was decreased at 12, 24, 36, and 48 weeks in women taking either the desogestrel or the gestodene combination, which indicated an increase in factor VII activity (p < 0,001); the decrease was slightly greater in those women taking the desogestrel combination. There was no observable difference between treatments in the treatment and posttreatment phases (p> 0,05). The maximal increase over the treatment phase has a positive slope ~ = 0.34 (p < 0.05), but Fig. 4 shows a decrease in the average time curve. Factor X. Factor X was increased at 12, 24, 36, and 48 weeks of treatment when compared with pretreatment levels in both groups (p < 0.001); the increase was slightly greater in the desogestrel group, Factor X activity 6 weeks after treatment was decreased from that at 48 weeks while receiving treatment. There was no observable difference between treatments in the treatment phase (p> 0.05), but 12 weeks after treatment
'" 25 % quartile - 1 box length
o
case reports: extreme values at least one box length below Q 25
Fig. l. Description of box plots.
there was a difference between the two treatment groups (p < 0.05). The level of factor X for the desogestrel group was higher than that for the gestodene group. The maximal increase over the treatment phase has a positive slope ~ = 0.14; Fig. 5 shows a slight increase in the average time curve. Antithrombin Ill. Antithrombin III levels were decreased at 36 weeks in women taking either combination (p < 0.01). At 6 weeks after treatment, the antithrombin III levels of both groups had returned to within the normal range. There were no observable differences in antithrombin III levels between treatments in the treatment and posttreatment phases (p> 0.05). The minimal decrease over the treatment phase has a positive slope ~ = 0.38; Fig. 6 shows a stable progression of the average time curve. Anti-Xa. There was no observable difference between treatments in the treatment and posttreatment phases (p> 0.05). The minimum decrease over the treatment phase has a negative slope ~ = - 0.11; Fig, 7 shows a slight decrease in the average time curve, Fibrinolytic system Plasminogen, Plasminogen levels at 12, 24, 36, and 48
432
Daly and Bonnar
July 1990 Am.J Obstet Gynecol
Gestodene left I Desogestrel right monophasIC gestocIene , alhlny\e8lradlol (FEMOOENE) monophasIC de8oge8treI , ethlnyle&lradlol lMARVELONI
20'" Prothrombin time
lsI
19 18 17
16
15 14
13
12 11 10~__~~__~__~~__~__.-~__~~.-~__,
12
Pre
24
36
48
6_ 12_
Weeks
Fig. 2. Effects of gestodene and desogestrel on prothrombin time.
Gestodene left I Desogestrel right
monophasIC gestocIene , alhlnyle&lradlol lFEMODENEI monophasIC desog88lnl1 , ethlnyle&lradlol lMARVELONI
60'" APTT (sl o
00
o
50
40
30~--.-~--~--.-~--~--r-~--~~r-~--. 12 24 36 48 6_ 12_ Weeks Pre
Fig. 3. Effects of gestodene and desogestrel on activated partial thromboplastin time.
Gestodene left I Desogestrel right monophasIC gestocIene , alhlnyle&lradlol (FEMODENE) monophasIC de8oge8treI , ethlnyIe&Iradlol lMARVB.ONI
20'" Factor VII
18
0
0
16
14
~~ 0
12
(sl
0 0
10
Pre
8
0 0
l~ ~~ 12
24
0
!~ 36
~~ ~a ~8 0
0 0
48
0
6 .... 12 ....
Fig. 4. Effects of gestodene and desogestrel on factor VII.
Weeks
Hemostatic effects of oral contraceptives 433
Volume 163 Number I, Part 2
Gestodene left I Desogestrel right rnonophaaIc ~ I elhlnyleelradlol (FEMODENE) rnonophaaIc deaogestreIl elhlnyleetradlol !MARVELON}
190'" Factor X ('MI) 170
o
150
o
130 110
r
90
I
70
~
Pre
12
24
36
48
6_ 12_
WeekS
Fig. 5. Effects of gestodene and desogestrel on factor X,
Gestodene left I Desogestrel right rnonophaaIc ~ I elhlnyleetradlol (FEMODEHEl rnonophaaIc deaogestreIl ethInyIMndIoI (MARVa0N)
170'" AntIthrombin III ('MI)
150 130
110 90 70
o
o
~ ~
f i~ ~ j.s: 0
24
Pre
36
48
6_ 12_
Weeks
Fig. 6. Effects of gestodene and desogestrel on antithrombin III.
Gestodene left I Desogestrel right rnonophaaIc ~ I ethlnyleetradlol (FEMODEHE) monophasic d8lOg88lrel1 ethlnylestradtol (MARVaON)
200'" AntI Xa ('MI) 0
180 160 140 120 100
80
60
~ .j 0
Pre
·0
12
0 0
.~ ~~ 24
~~ l~ ~~ 0
o
00
0
36
Fig. 7. Effects of gestodene and desogestrel on anti-Xa.
434
Daly and Bonnar
July 1990 Am J Obstet Gynecol
Gestodene left I Desogestrel right monophaaIc gestodene / elhtnyle8lradlol (FEM()OENE) monophaaIc ~ / 8\111n)1esIrad1ol (MARVELON)
200'" Plasminogen
(%) 0
8@
175 150
125 100
75
~ ~ 0
0
8
50
12
Pre
~ ~~
o o
0
24
36
48
6_ 12_
Weeks
Fig. 8. Effects of gestodene and desogestrel on plasminogen.
Gestodene left I Desogestrel right monophaaIc gestodene / ethl~ (FEMODENE) monophaaIc deeogesIreI/ ~101 (MARVELON)
170'" Antiplasmln (%) 150 130
no 90 70
0
9
0
~~~ ~I ~~ ~ ~
~ o~ 1
!
0
0
50 Pre
12
24
0
00
36
48
0
9
6_ 12_
Weeks
Fig. 9. Effects of gestodene and desogestrel on anti plasmin.
weeks were increased by both pills (p < 0.001). There was a difference between treatments in the treatment phase (p < 0.05), and there was no difference between treatments 12 weeks after treatment (p> 0.05). The plasminogen level was higher in the gestodene group than in the desogestrel group. The maximal increase over the treatment phase has a positive slope ~ = 0.08; Fig. 8 shows a slight increase in the average time curve. Antiplasmin. There was no observable difference between treatments in the treatment phase (P > 0.05), but there was a difference between the two treatment groups 12 weeks after treatment (P < 0.05). The antiplasmin level was higher in the desogestrel group than in the gestodene group. The maximal increase over the treatment phase has a negative slope ~ = - 0.33; Fig. 9 shows a slight decrease in the average time curve.
Fibrinogen. Fibrinogen levels increased with both pills (P 0.05). The maximal increase over the treatment phase has a positive slope ~ = 0.24; Fig. 10 shows a slight increase in the average time curve. Fibrinolytic activity. Fibrinolytic activity increased from 12 weeks on treatment in both groups (P < 0.001). During treatment increased fibrinolytic activity was sustained and rapidly returned to pretreatment levels 6 weeks after the pill was stopped. There was no observable difference between treatments in the treatment and posttreatment phases (P > 0.05). The maximal increase over the treatment phase has a positive slope
Hemostatic effects of oral contraceptives
Volume 163 Number I, Part 2
435
Gestodene left I Desogestrel rtght monop/IaIIC geetodane / ~ (FEMODENE) monop/IaIIC de8oged'eI/ ~ (MARVELON)
500 '" Abrtnogen (mg /
wo mO
450
o
,! !~ ~~~
400 350
300 250 200
150 @
WO~--~~~-r--~--~~---r--'---r-~---r--' 12 24 36 Pre 48 6 .... 12.... Weeks
Fig. 10. Effects of gestodene and desogestrel on fibrinogen.
Gestodene left I Desogestrel rtght monop/IaIIC geetodane / 8IhInyIeaIradIoI (FEMODENE) monop/IaIIC de8oged'eI/ eIhInyIeetradIo (MARVELON)
380 '" Abltnolytk: ActMIy (mm 2 ) 0
330 0
oT
280 230
180
130
80
0
~ Pre
0 0 0
~J ~~ 0
0
12
24
!
36
00 0
••
1 48
0
§~ ~B
6 .... 12....
Weeks
Fig. 11. Effects of gestodene and desogestrel on fibrinolytic activity.
13 = 0.22; Fig. 11 shows a slight increase in the average time curve. Platelets Platelets aggregation. Platelet aggregation was decreased in both groups and the decrease was greater in the desogestrel group (p < 0.001) than in the gestodene group (p < 0.01). There was no observable difference between treatments in the treatment and posttreatment phases (p> 0.05). The minimal decrease over the treatment phase has a slope 13 = 0.20, but Fig. 12 shows a slight decrease in the average time curve. Platelet count. There was no observable difference between treatments in the treatment and posttreatment phases (p > 0.05). The maximal increase over the treatment phase has a slope 13 = 0.00; Fig. 13 shows a stable progression in the average time curve.
Comment
The new low-dose estrogen/progestogen oral contraceptives induce major changes in the coagulation and fibrinolytic systems and in platelet function. The prothrombin time and activated partial thromboplastin time, which measure the overall activity of the extrinsic and intrinsic coagulation pathways, respectively, showed no significant changes with both oral contraceptive formulations. This indicates that the overall effects of the new pills are less than what occurs with the 50 fJ.g pills that induce significant changes in these tests. 9 Likewise, changes in the coagulation system with respect to factor X, antithrombin III, and platelet aggregation are not as marked with the new low-dose monophasic oral contraceptives as with those previously studied that contained 50 fJ.g of estrogen. 10 Both estro-
436
Daly and Bonnar
July 1990 Am J Obstet Gynecol
Gestodene left I Desogestrel right monophasic gestodene 1 elhlnytestradlol (FEMODENE) monophasic deaogestreIl elhlnylestracllOl (MARVELON)
1000'" Platelet Aggregation (s)
o
650
700 550
.~ 0
400 250
0
0
0 0
Pre
8
~
0
.~ 0
0
0 0
~~ $~ ~~~~ 0
0
24
12
36
48
6"", 12"",
Weeks
Fig. 12. Effects of gestodene and desogestrel on platelet aggregation.
Gestodene left I Desogestrel right monophasic gestodene 1 elhlnylestradlol (RMODENE) monophasic de8oge8trel 1 elhlnytestradlOl (MARVELON)
550'" Platelet Count
Ix 10 3 ,
mm 3 )
0
0
470 390
310 230
~~ !~ 0
150
8
~
12
.~
1
0
n
Pre
l
0
24
36
~. ~~ ~! 0
0
48
6"", 12"",
Weeks
Fig. 13. Effects of gestodene and desogestrel on platelet count.
gen/progestogen pills increased significantly the activity or factors V II and X, and the greater increase with the desogestrel pill suggests this combination has a greater estrogenic effect. Plasminogen and fibrinolytic activity were markedly increased by both hormonal preparations, and this enhancement of fibrinolysis is likely to counteract the increase in fibrinogen and coagulation activity that protects the dynamic balance between coagulation and fibrinolysis. Platelet aggregation was decreased by both pills and more so by the desogestrel combination. This would seem to be an undesirable effect. The low-dose oral contraceptives with the new progestogens studied induce marked changes in the hemostatic system, in particular, enhanced activity of factors VII and X and acceleration of platelet aggregation.
These changes in the physiology of hemostasis suggest that these new pills will also carry a thrombogenic hazard in susceptible women. The effects on hemostasis arise from the overall estrogenic activity, which is determined by the progestogen used in combination with the estrogen. More research is required to find whether effective combinations can be obtained that will induce fewer changes in the hemostatic system and other physiologic processes. Meantime, it would be unwise for any claims to be made that oral contraceptives with the new progestogens, gestodene and desogestrel, will be free of vascular complications. We acknowledge the technical help of Lucy Norris and the detailed supervision of the women carried out by research nurses, Eilis Carroll and Bernadette Hennelly. We also thank the women who kindly agreed to
Hemostatic effects of oral contraceptives
Volume 163 Number I, Part 2
take part in this study and Dr. T. Louton of the Statistics Department, Schering AG, Berlin, who kindly carried out the analysis of covariance and prepared the box plots.
14.
15.
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