Effect of the menstrual cycle, oral contraception and pregnancy on forearm blood flow, venous distensibility and clotting factors

Abstract

Forearm blood flow, venous distensibility and various clotting factors were determined in 118 apparently healthy women (mean age 26 years), either during the menstrual cycle, or while taking a combined contraceptive (A) with high progestin:estrogen ratio (d-norgestrel 0.125 mg + ethinylestradiol 0.03 mg), or a sequential contraceptive (B) with low progestin: estrogen ratio (megestrol 0.1/1 mg + ethinylestradiol 0.1 mg), or in the 1st, 2nd and 3rd trimester of pregnancy. Venous distensibility in women taking contraceptive A was higher than in other women during the follicular phase of a normal menstrual cycle. Venous distensibility was not affected by contraceptive B. Blood flow and blood pressure remained unchanged by contraceptives A and B. Fibrinogen concentration was increased by both contraceptives, factor VII was either decreased (A) or unchanged (B), and factor X was either unchanged (A) or increased (B). The oral contraceptive with the high progestagen component appeared to increase venous capacitance and may induce venous stasis, whereas coagulability was particularly enhanced by the estrogen-type contraceptive. Pregnant women differed from women on oral contraceptives in regard to peripheral circulation; they showed a tremendous increase of blood flow with secondary vasodilation.

Effects of menstrual cycle and oral contraceptive use on calf venous compliance

“…This finding was surprising in light of previous research in which most (1,7,10,22,23,40) but not all (6) studies have shown that variations in exogenous and endogenous forms of the female sex hormones change the distensibility of the veins.…”

“…tive use (7,10) and pregnancy (1,7,10,23). However, Duncan et al (6) found no difference in the distensibility of the veins during pregnancy.…”

“…This potentially means that venous compliance of women during certain hormone profiles may be equal to or greater than that of men; these changes may increase women's cardiovascular stress and possibly their susceptibility to orthostatic intolerance during certain phases of the menstrual cycle or oral contraceptive use. To date, the effects of the menstrual cycle and oral contraceptive use on orthostatic tolerance are unclear.Earlier studies provided conflicting results regarding the effects of estrogen and progesterone on the veins (1,6,7,9,10,22, 23,40). The inconsistent results of these studies may be due in part to the use of different experimental approaches employed to study venous compliance or regional differences in response to estrogen and progesterone.…”

“…Earlier studies provided conflicting results regarding the effects of estrogen and progesterone on the veins (1,6,7,9,10,22,23,40). The inconsistent results of these studies may be due in part to the use of different experimental approaches employed to study venous compliance or regional differences in response to estrogen and progesterone.…”

Maternal Heart Rate and Stroke Volume in the Pygmy Goat: Effects of Exercise and Cardiac Autonomic Blockade

“…However, the presence of this phenomenon in quadrupedal animals might point to a different aetiology. Venous capacitance is increased in pregnancy (Fawer, Dettling, Weihs, Weltl & Schelling, 1978) possibly due to the effects of elevated levels of circulating progesterone (Fawer et al 1978). After the abrupt offest of exercise with the loss of the peripheral 'muscle pump' aiding venous return, venous blood might have a greater tendency to pool peripherally.…”