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The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes
Dissertation (MSc (Human Physiology))--University of Pretoria, 2018.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613469873799168 |
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| access_status_str | Open Access |
| author2 | Swanepoel, A.C. |
| author_browse | Swanepoel, A.C. |
| author_facet | Swanepoel, A.C. |
| collection | Thesis |
| description | Dissertation (MSc (Human Physiology))--University of Pretoria, 2018. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110073 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:36:39.169Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110073 The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes Swanepoel, A.C. odetteemmerson@gmail.com Lindeque, B.G. Bester, Janette Emmerson, Odette combined oral contraceptives drospirenone ethinyl estradiol hypercoagulation haemostasis venous thrombosis erythrocytes platelets fibrin rouleaux formation Dissertation (MSc (Human Physiology))--University of Pretoria, 2018. An estimated 13% of women of reproductive age worldwide are currently using combined oral contraceptives (COCs). Numerous incidents of venous thrombosis (VT) have been associated with the use of COCs. Synthetic hormones cause a shift in haemostasis to a hypercoagulable state. The current study investigated the impact of two ethinyl estradiol (EE) and drospirenone (DRSP) containing COCs namely Yasmin®(DRSP/30EE) and Yaz®(DRSP/20EE) on the viscoelasticity of whole blood clots as well as the biophysical and biochemical characteristics of erythrocytes . Various techniques provided an integrate approach to this study. Erythrocyte sedimentation rate (ESR), whole blood analysis (Haemanalyser), thromboelastography (TEG), microscopy techniques namely light microscopy (LM), scanning microscopy (SEM) and laser scanning confocal microscopy (LSCM) along with the global thrombosis test (GTT) were used to investigate the impact of the two mentioned COCs on whole blood. ESR showed no indication of inflammation. Whole blood counts showed little difference between the three respective groups. TEG analysis showed a tendency towards a hypercoagulable state in the COCs groups, but more pronounced with higher EE concentrations. LM and SEM showed rouleaux formation (coinlike stacking) of the erythrocytes as well as morphological alterations to the erythrocyte shape for the COC groups, which was attributed to membrane damage. SEM analysis also showed spontaneous activation of fibrin and platelets in the COC groups, along with interactions between erythrocytes and platelets and/or fibrin. Confocal microscopy confirmed compromised membrane integrity in the COC groups compared to the controls. GTT analysis showed increased platelet activation and low thrombolysis in both the COC groups when compared to the controls. In conclusion, Yaz® and Yasmin® impact the erythrocytes biophysical as well as their biochemical properties to cause a shift in haemostasis to a hypercoagulable or prothrombotic state. Any disruptions to the erythrocyte membrane effect the normal functioning of the cells which could lead to vascular obstruction as the flow rate and viscosity is affected by COCs usage. Although these effects are mostly subclinical the long-term effects and risks involved with the use of these hormones should be considered carefully for each individual. Physiology MSc (Human Physiology) 2026-05-15T17:26:14Z 2026-05-15T17:26:14Z 18/03/22 2018 Dissertation http://hdl.handle.net/2263/110073 en application/pdf |
| spellingShingle | combined oral contraceptives drospirenone ethinyl estradiol hypercoagulation haemostasis venous thrombosis erythrocytes platelets fibrin rouleaux formation The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes |
| title | The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes |
| title_full | The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes |
| title_fullStr | The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes |
| title_full_unstemmed | The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes |
| title_short | The impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes |
| title_sort | impact of combined oral contraceptives containing ethinyl estradiol and drospirenone on whole blood clot viscoelasticity and the biophysical and biochemical characteristics of erythrocytes |
| topic | combined oral contraceptives drospirenone ethinyl estradiol hypercoagulation haemostasis venous thrombosis erythrocytes platelets fibrin rouleaux formation |
| url | http://hdl.handle.net/2263/110073 |