Stroke

Most users of hormonal contraceptives (HCs) have a low background incidence of major cardiovascular diseases.

In fact,current users of low estrogen dose – HC s have a small increased risk of ischaemic stroke, although most of the risk occurs in women with other risk factors, notably hypertension, age, smoking, and a history of migraine ^(20,21,22).

Particularly, the risk of ischaemic stroke among current users with a history of hypertension was evaluated 10.7 (odds ratio) ⁽²³⁾.

Similarly, the use of HC increases the risk of haemorrhagic stroke in women aged over 35 years (odds ratio greater than 2) and when they have a history of hypertension, this risk is 10-15 fold compared with women who did not use COC s and did not have a history of hypertension ⁽²⁴⁾.

Odds ratio among current users who are also current cigarette smokers was greater than 3. Past users of HCs do not seem to have an increased risk of stroke.
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The risks are similar for subarachnoid and intracerebral haemorrhage. ⁽²⁵⁾. After the introduction of low-dose oral contraceptives, a decline in cerebral thromboembolism among young women has been reported ⁽²⁶⁾.

However, cerebrovascular occlusion in young women may be caused by hormonal contraceptive use when unsuspected free protein S or protein C deficiency, coagulation factor XIII gene variation or inherited thrombophilia exist ^{(27,28,29,30)}.

The role of inherited prothrombotic conditions as factor V Leiden, and prothrombin mutation in the pathogenesis of ischemic stroke is not well established; although it seems that carriers of the factor V Leiden mutation might have a 11.2 fold higher risk of ischemic stroke than women without either risk factor ^(31,32).

A prospective cohort study on 44,408 women on low-dose oral contraceptives and 75,230 with an intrauterine device(IUD) followed during three years, reported a higher incidence of haemorrhagic stroke than ischemic stroke (34.74 versus 11.25 per 100,000 woman years)for HC users.
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The relative risk (RR) of incidence of haemorrhagic stroke was 2.72 times compared with that in the IUD users. Furthermore, the RR of current users of HC was 4.20 and still reached 2.17 among past users after they stopped taking HC for more than 10 years ⁽³³⁾.

While,other studies had found no statistically significant increase in the risk of stroke among HC past users without other risk factors.In fact, for past users compared with never users the odds ratio was 0.59 ⁽³⁴⁾.

Current users of low-dose oral contraceptives had a risk for stroke similar to that of women who have never used these medications and the results did not differ appreciably between hemorrhagic stroke and ischaemic stroke.