Antithrombin III and Platelets during the Normal Menstrual Cycle and in Women Receiving Oral Contraceptives Low in Oestrogen

Abstract

Determinations of platelet number and concentration of antithrombin III (AT-III) were made in samples of plasma collected during one normal or hormone-simulated cycle in 14 young, normal women and in 11 women using an oral contraceptive low in oestrogen. Distinct, individual levels caused the variation of both parameters to be greater within the group than individually. Despite a few exceptions, a slight but statistically significant increase in the platelet number and AT-III level occurred around midcycle in the normal group. In the hormone group the platelet number increased slightly in the treatment period, while the AT-III level showed a corresponding slight decrease. The large decreases in AT-III levels reported by other authors testing oral contraceptives high in oestrogen were not seen in our study.

Levels of Protein S during the Normal Menstrual Cycle and in Women on Oral Contraceptives Low in Estrogen

“…However, during the period of OC consumption a slight but statistically significant decrease could be demonstrated. A similar finding was previously seen in antithrombin-111 concentration [5], while protein C was unchanged [9].…”

“…148 153 122 156 142 15 3 103 105 108 103 103 104 2 4 97 103 95 90 93 96 5 7 94 96 103 75 96 93 11 9 126 157 115 112 103 123 21 11 112 113 110 122 125 116 7 12 126 98 90 94 128 107 18 13 115 104 110 108 108 109 4 15 109 117 98 104 99 105 8 17 87 86 93 79 72 83 8 20 -101 98 95 98 98 2 x period 110 112 107 100 107 SD period 15 22 17 16 22 Blood samples were collected during selected periods (1)(2)(3)(4)(5). Concentration expressed as percentages of the concentration in the reference plasma.…”

“…The problem of causality thus remains enigmatic [2,3], The reported decrease in the concentration in plasma of antithrombin-III, the main inhibitor of thrombin, following administration of OC [4], gained increased interest, when it was found that women with hereditary antithrombin-III deficiency ex hibited a particular high risk of thromboembolism dur ing pregnancy or when treated with OC [for a review, see ref. 3], However, decreases in antithrombin-III concen tration during one hormone period (cycle) are small in otherwise normal women taking 30 or 50 pg ethinyl estradiol [5,6], and they are therefore difficult to recon cile with the alleged causal relationship between a de crease in antithrombin-III concentration and thrombo embolism caused by OC.…”

Circadian Variation within Hemostasis: An Underrecognized Link between Biology and Disease?

“…60 A slight but statistically significant increase in platelet number and antithrombin (AT) level around midcycle has also been reported. 61 Madden and colleagues observed a circadian rhythm in vascular cell adhesion molecule-1 (VCAM-1)positive cell microparticles (MPs) and less so tissue factor-positive MPs, evaluated in 11 healthy male subjects. 62 MPs are shed into the circulation from activated/ damaged endothelium due to membrane remodeling 63 and from many other types of cells, including platelets, 64 endothelium, 65 leukocytes 66 and red blood cells 67 upon activation, apoptosis, and under normal physiologic conditions.…”

Response of Serine Antiproteases to Growth Hormone Therapy in Growth Hormone Deficient Children

“…Antithrombin III levels did not change during pregnancy [ 18]. Serum anti thrombin III levels decreased with either estrogen or combined estrogen/progestogen agents [ 19], ai-Antitryp sin does not vary during the menstrual cycle [20], while there is a slight increase in antithrombin III level in mid cycle [21], No information is available on the effect of the menstrual cycle on ai-antichymotrypsin. In our study, only 3 patients had a change in Tanner staging over the course of the study.…”