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Uygur L, Kabasakal Ilter M, Helvacı N, Mokresh ME, Kahya M, Muvaffak E, Elmuhammed MH, Ayhan I, Kumru P. Investigating the blood rheology in the first trimester pregnancies with high risk for preeclampsia. Clin Hemorheol Microcirc 2024; 86:519-530. [PMID: 38143340 DOI: 10.3233/ch-232026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
BACKGROUND Pregnancy is a dynamic process associated with changes in vascular and rheological resistance. Maternal maladaptation to these changes is the leading cause of pregnancy complications such as preeclampsia. OBJECTIVE This study aimed to assess the hemorheological alterations in pregnancies with a high risk for preeclampsia in the first trimester. METHODS Ninety-two pregnant women were allocated into the high preeclampsia risk group (37 cases) and control groups (55 cases). Plasma and whole blood viscosity and red blood cell morphodynamic properties, including deformability and aggregation were assessed by Brookfield viscometer and laser-assisted optical rotational cell analyzer (LORRCA) at 11-14 gestational weeks. RESULTS Whole blood viscosity was significantly higher in the high-risk group at all shear rates. Plasma viscosity and hematologic factors showed no differences between the groups. Hematocrit levels positively correlated with high blood viscosity only in the high-risk group. There were no significant changes in the other deformability and aggregation parameters. CONCLUSIONS Changes in the whole blood viscosity of pregnant women with high preeclampsia risk refer to impaired microcirculation beginning from the early weeks of gestation. We suggest that the whole blood viscosity is consistent with the preeclampsia risk assessment in the first trimester, and its measurement might be promising for identifying high-preeclampsia-risk pregnancies.
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Affiliation(s)
- Lutfiye Uygur
- Department of Obstetrics and Gynecology, Division of Perinatology, Zeynep Kamil Women and Children Health Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Merve Kabasakal Ilter
- Department of Medical Pharmacology, Hamidiye Faculty of Medicine, University of Health Sciences, Istanbul, Turkey
| | - Nazlı Helvacı
- Department of Biochemistry, Hamidiye Faculty of Medicine, University of Health Sciences, Istanbul, Turkey
| | - Muhammed Edib Mokresh
- Hamidiye International School of Medicine, University of Health Sciences, Istanbul, Turkey
| | - Muhammed Kahya
- Hamidiye International School of Medicine, University of Health Sciences, Istanbul, Turkey
| | - Emir Muvaffak
- Hamidiye International School of Medicine, University of Health Sciences, Istanbul, Turkey
| | | | - Isil Ayhan
- Department of Obstetrics and Gynecology, Division of Perinatology, Zeynep Kamil Women and Children Health Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Pınar Kumru
- Department of Obstetrics and Gynecology, Zeynep Kamil Women and Children Health Research Hospital, University of Health Sciences, Istanbul, Turkey
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Csiszar B, Galos G, Funke S, Kevey DK, Meggyes M, Szereday L, Kenyeres P, Toth K, Sandor B. Peripartum Investigation of Red Blood Cell Properties in Women Diagnosed with Early-Onset Preeclampsia. Cells 2021; 10:cells10102714. [PMID: 34685694 PMCID: PMC8534376 DOI: 10.3390/cells10102714] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 01/25/2023] Open
Abstract
We investigated peripartum maternal red blood cell (RBC) properties in early-onset preeclampsia (PE). Repeated blood samples were taken prospectively for hemorheological measurements at PE diagnosis (n = 13) or during 26-34 weeks of gestation in healthy pregnancies (n = 24), then at delivery, and 72 h postpartum. RBC aggregation was characterized by M index (infrared light transmission between the aggregated RBCs in stasis) and aggregation index (AI-laser backscattering from the RBC aggregates). We observed significantly elevated RBC aggregation (M index = 9.8 vs. 8.5; AI = 72.9% vs. 67.5%; p < 0.001) and reduced RBC deformability in PE (p < 0.05). A positive linear relationship was observed between AI and gestational age at birth in PE by regression analysis (R2 = 0.554; p = 0.006). ROC analysis of AI showed an AUC of 0.84 (0.68-0.99) (p = 0.001) for PE and indicated a cutoff of 69.4% (sensitivity = 83.3%; specificity = 62.5%), while M values showed an AUC of 0.75 (0.58-0.92) (p = 0.019) and indicated a cutoff of 8.39 (sensitivity = 90.9% and specificity = 50%). The predicted probabilities from the combination of AI and M variables showed increased AUC = 0.90 (0.79-1.00) (p < 0.001). Our results established impaired microcirculation in early-onset PE manifesting as deteriorated maternal RBC properties. The longer the pathologic pregnancy persists, the more pronounced the maternal erythrocyte aggregation. AI and M index could help in the prognostication of early-onset PE, but further investigations are warranted to confirm the prognostic role before the onset of symptoms.
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Affiliation(s)
- Beata Csiszar
- Department of Anaesthesiology and Intensive Therapy, Medical School, University of Pécs, H-7624 Pécs, Hungary
- Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary; (G.G.); (M.M.); (L.S.); (P.K.); (K.T.); (B.S.)
- Correspondence:
| | - Gergely Galos
- Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary; (G.G.); (M.M.); (L.S.); (P.K.); (K.T.); (B.S.)
- 1st Department of Medicine, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Simone Funke
- Department of Obstetrics and Gynaecology, Medical School, University of Pécs, H-7624 Pécs, Hungary; (S.F.); (D.K.K.)
| | - Dora Kinga Kevey
- Department of Obstetrics and Gynaecology, Medical School, University of Pécs, H-7624 Pécs, Hungary; (S.F.); (D.K.K.)
| | - Matyas Meggyes
- Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary; (G.G.); (M.M.); (L.S.); (P.K.); (K.T.); (B.S.)
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Laszlo Szereday
- Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary; (G.G.); (M.M.); (L.S.); (P.K.); (K.T.); (B.S.)
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Peter Kenyeres
- Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary; (G.G.); (M.M.); (L.S.); (P.K.); (K.T.); (B.S.)
- 1st Department of Medicine, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Kalman Toth
- Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary; (G.G.); (M.M.); (L.S.); (P.K.); (K.T.); (B.S.)
- 1st Department of Medicine, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Barbara Sandor
- Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary; (G.G.); (M.M.); (L.S.); (P.K.); (K.T.); (B.S.)
- 1st Department of Medicine, Medical School, University of Pécs, H-7624 Pécs, Hungary
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Abalos E, Duley L, Steyn DW, Gialdini C. Antihypertensive drug therapy for mild to moderate hypertension during pregnancy. Cochrane Database Syst Rev 2018; 10:CD002252. [PMID: 30277556 PMCID: PMC6517078 DOI: 10.1002/14651858.cd002252.pub4] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Antihypertensive drugs are often used in the belief that lowering blood pressure will prevent progression to more severe disease, and thereby improve pregnancy outcome. This Cochrane Review is an updated review, first published in 2001 and subsequently updated in 2007 and 2014. OBJECTIVES To assess the effects of antihypertensive drug treatments for women with mild to moderate hypertension during pregnancy. SEARCH METHODS We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (13 September 2017), and reference lists of retrieved studies. SELECTION CRITERIA All randomised trials evaluating any antihypertensive drug treatment for mild to moderate hypertension during pregnancy, defined as systolic blood pressure 140 to 169 mmHg and/or diastolic blood pressure 90 to 109 mmHg. Comparisons were of one or more antihypertensive drug(s) with placebo, with no antihypertensive drug, or with another antihypertensive drug, and where treatment was planned to continue for at least seven days. DATA COLLECTION AND ANALYSIS Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. MAIN RESULTS For this update, we included 63 trials (data from 58 trials, 5909 women), with moderate to high risk of bias overall.We carried out GRADE assessments for the main 'antihypertensive drug versus placebo/no antihypertensive drug' comparison only. Evidence was graded from very low to moderate certainty, with downgrading mainly due to design limitations and imprecision.For many outcomes, trials contributing data evaluated different hypertensive drugs; while we did not downgrade for this indirectness, results should be interpreted with caution.Antihypertensive drug versus placebo/no antihypertensive drug (31 trials, 3485 women)Primary outcomes: moderate-certainty evidence suggests that use of antihypertensive drug(s) probably halves the risk of developing severe hypertension (risk ratio (RR) 0.49; 95% confidence interval (CI) 0.40 to 0.60; 20 trials, 2558 women), but may have little or no effect on the risk of proteinuria/pre-eclampsia (average risk ratio (aRR) 0.92; 95% CI 0.75 to 1.14; 23 trials, 2851 women; low-certainty evidence). Moderate-certainty evidence also shows that antihypertensive drug(s) probably have little or no effect in the risk of total reported fetal or neonatal death (including miscarriage) (aRR 0.72; 95% CI 0.50 to 1.04; 29 trials, 3365 women), small-for-gestational-age babies (aRR 0.96; 95% CI 0.78 to 1.18; 21 trials, 2686 babies) or preterm birth less than 37 weeks (aRR 0.96; 95% CI 0.83 to 1.12; 15 trials, 2141 women). SECONDARY OUTCOMES we are uncertain of the effect of antihypertensive drug(s) on the risk of maternal death, severe pre-eclampsia, or eclampsia, orimpaired long-term growth and development of the baby in infancy and childhood, because the certainty of this evidence is very low. There may be little or no effect on the risk of changed/stopped drugs due to maternal side-effects, or admission to neonatal or intensive care nursery (low-certainty evidence). There is probably little or no difference in the risk of elective delivery (moderate-certainty evidence).Antihypertensive drug versus another antihypertensive drug (29 trials, 2774 women)Primary outcomes: beta blockers and calcium channel blockers together in the meta-analysis appear to be more effective than methyldopa in avoiding an episode of severe hypertension (RR 0.70; 95% CI 0.56 to 0.88; 11 trials, 638 women). There was also an increase in this risk when other antihypertensive drugs were compared with calcium channel blockers (RR 1.86; 95% CI 1.09 to 3.15; 5 trials, 223 women), but no evidence of a difference when methyldopa and calcium channel blockers together were compared with beta blockers (RR1.18, 95% CI 0.95 to 1.48; 10 trials, 692 women). No evidence of a difference in the risk of proteinuria/pre-eclampsia was found when alternative drugs were compared with methyldopa (aRR 0.78; 95% CI 0.58 to 1.06; 11 trials, 997 women), with calcium channel blockers (aRR: 1.24, 95% CI 0.70 to 2.19; 5 trials, 375 women), or with beta blockers (aRR 1.21, 95% CI 0.88 to 1.67; 12 trials, 1107 women).For the babies, we found no evidence of a difference in the risk oftotal reported fetal or neonatal death (including miscarriage) when comparing other antihypertensive drugs with methyldopa (aRR 0.77, 95% CI 0.52 to 1.14; 22 trials, 1791 babies), with calcium channel blockers (aRR 0.90, 95% CI 0.52 to 1.57; nine trials, 700 babies), or with beta blockers (aRR: 1.23, 95% CI 0.81 to 1.88; 19 trials, 1652 babies); nor in the risk for small-for-gestational age in the comparison with methyldopa (aRR 0.79, 95% CI 0.52 to 1.20; seven trials, 597 babies), with calcium channel blockers (aRR 1.05, 95% CI 0.64 to 1.73; four trials, 200 babies), or with beta blockers (average RR 1.13, 95% CI 0.80 to 1.60; 7 trials, 680 babies). No evidence of an overall difference among groups in the risk of preterm birth (less than 37 weeks) was found in the comparison with methyldopa (aRR: 0.91; 95% CI 0.68 to 1.22; 11 trials, 835 women), with calcium channel blockers (aRR 0.85, 95% CI 0.59 to 1.23; six trials, 330 women), or with beta blockers (aRR 1.22, 95% CI 0.90 to 1.66; 9 trials, 806 women). SECONDARY OUTCOMES There were no cases of maternal death andeclampsia. There is no evidence of a difference in the risk of severe pre-eclampsia, changed/stopped drug due to maternal side-effects, elective delivery, admission to neonatal or intensive care nursery when other antihypertensive drugs are compared with methyldopa, calcium channel blockers or beta blockers. Impaired long-term growth and development in infancy and childhood was not reported for these comparisons. AUTHORS' CONCLUSIONS Antihypertensive drug therapy for mild to moderate hypertension during pregnancy reduces the risk of severe hypertension. The effect on other clinically important outcomes remains unclear. If antihypertensive drugs are used, beta blockers and calcium channel blockers appear to be more effective than the alternatives for preventing severe hypertension. High-quality large sample-sized randomised controlled trials are required in order to provide reliable estimates of the benefits and adverse effects of antihypertensive treatment for mild to moderate hypertension for both mother and baby, as well as costs to the health services, women and their families.
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Affiliation(s)
- Edgardo Abalos
- Centro Rosarino de Estudios Perinatales (CREP)Moreno 878, 6th floorRosarioSanta FeArgentinaS2000DKR
| | - Lelia Duley
- Nottingham Health Science PartnersNottingham Clinical Trials UnitC Floor, South BlockQueen's Medical CentreNottinghamUKNG7 2UH
| | - D Wilhelm Steyn
- University of StellenboschObstetrics & GynaecologyDepartment of Obstetrics & GynaecologyPO Box 19063TygerbergStellenboschSouth Africa7505
| | - Celina Gialdini
- Centro Rosarino de Estudios Perinatales (CREP)Department of Obstetrics, Hospital Provincial de RosarioMoreno 878, 6th floorRosarioArgentinaS2000DKR
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Abalos E, Duley L, Steyn DW. Antihypertensive drug therapy for mild to moderate hypertension during pregnancy. Cochrane Database Syst Rev 2014:CD002252. [PMID: 24504933 DOI: 10.1002/14651858.cd002252.pub3] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Mild to moderate hypertension during pregnancy is common. Antihypertensive drugs are often used in the belief that lowering blood pressure will prevent progression to more severe disease, and thereby improve the outcome. OBJECTIVES To assess the effects of antihypertensive drug treatments for women with mild to moderate hypertension during pregnancy. SEARCH METHODS We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2013) and reference lists of retrieved studies. SELECTION CRITERIA All randomised trials evaluating any antihypertensive drug treatment for mild to moderate hypertension during pregnancy defined, whenever possible, as systolic blood pressure 140 to 169 mmHg and diastolic blood pressure 90 to 109 mmHg. Comparisons were of one or more antihypertensive drug(s) with placebo, with no antihypertensive drug, or with another antihypertensive drug, and where treatment was planned to continue for at least seven days. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data. MAIN RESULTS Forty-nine trials (4723 women) were included. Twenty-nine trials compared an antihypertensive drug with placebo/no antihypertensive drug (3350 women). There is a halving in the risk of developing severe hypertension associated with the use of antihypertensive drug(s) (20 trials, 2558 women; risk ratio (RR) 0.49; 95% confidence interval (CI) 0.40 to 0.60; risk difference (RD) -0.10 (-0.13 to -0.07); number needed to treat to harm (NNTH) 10 (8 to 13)) but little evidence of a difference in the risk of pre-eclampsia (23 trials, 2851 women; RR 0.93; 95% CI 0.80 to 1.08). Similarly, there is no clear effect on the risk of the baby dying (27 trials, 3230 women; RR 0.71; 95% CI 0.49 to 1.02), preterm birth (15 trials, 2141 women; RR 0.96; 95% CI 0.85 to 1.10), or small-for-gestational-age babies (20 trials, 2586 women; RR 0.97; 95% CI 0.80 to 1.17). There were no clear differences in any other outcomes.Twenty-two trials (1723 women) compared one antihypertensive drug with another. Alternative drugs seem better than methyldopa for reducing the risk of severe hypertension (11 trials, 638 women; RR (random-effects) 0.54; 95% CI 0.30 to 0.95; RD -0.11 (-0.20 to -0.02); NNTH 7 (5 to 69)). There is also a reduction in the overall risk of developing proteinuria/pre-eclampsia when beta blockers and calcium channel blockers considered together are compared with methyldopa (11 trials, 997 women; RR 0.73; 95% CI 0.54 to 0.99). However, the effect on both severe hypertension and proteinuria is not seen in the individual drugs. Other outcomes were only reported by a small proportion of studies, and there were no clear differences. AUTHORS' CONCLUSIONS It remains unclear whether antihypertensive drug therapy for mild to moderate hypertension during pregnancy is worthwhile.
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Affiliation(s)
- Edgardo Abalos
- Centro Rosarino de Estudios Perinatales (CREP), Moreno 878, 6th floor, Rosario, Santa Fe, Argentina, S2000DKR
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Abalos E, Duley L, Steyn DW, Henderson-Smart DJ. Antihypertensive drug therapy for mild to moderate hypertension during pregnancy. Cochrane Database Syst Rev 2007:CD002252. [PMID: 17253478 DOI: 10.1002/14651858.cd002252.pub2] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Mild to moderate hypertension during pregnancy is common. Antihypertensive drugs are often used in the belief that lowering blood pressure will prevent progression to more severe disease, and thereby improve outcome. OBJECTIVES To assess the effects of antihypertensive drug treatments for women with mild to moderate hypertension during pregnancy. SEARCH STRATEGY We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2005, Issue 3), MEDLINE (1966 to November 2005), LILACS (1984 to November 2005) and EMBASE (1974 to November 2005). SELECTION CRITERIA All randomised trials evaluating any antihypertensive drug treatment for mild to moderate hypertension during pregnancy defined, whenever possible, as systolic blood pressure 140 to 169 mmHg and diastolic blood pressure 90 to 109 mmHg. Comparisons were of one or more antihypertensive drug(s) with placebo, with no antihypertensive drug, or with another antihypertensive drug, and where treatment was planned to continue for at least seven days. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data. MAIN RESULTS Forty-six trials (4282 women) were included. Twenty-eight trials compared an antihypertensive drug with placebo/no antihypertensive drug (3200 women). There is a halving in the risk of developing severe hypertension associated with the use of antihypertensive drug(s) (19 trials, 2409 women; relative risk (RR) 0.50; 95% confidence interval (CI) 0.41 to 0.61; risk difference (RD) -0.10 (-0.12 to -0.07); number needed to treat (NNT) 10 (8 to 13)) but little evidence of a difference in the risk of pre-eclampsia (22 trials, 2702 women; RR 0.97; 95% CI 0.83 to 1.13). Similarly, there is no clear effect on the risk of the baby dying (26 trials, 3081 women; RR 0.73; 95% CI 0.50 to 1.08), preterm birth (14 trials, 1992 women; RR 1.02; 95 % CI 0.89 to 1.16), or small-for-gestational-age babies (19 trials, 2437 women; RR 1.04; 95 % CI 0.84 to 1.27). There were no clear differences in any other outcomes. Nineteen trials (1282 women) compared one antihypertensive drug with another. Beta blockers seem better than methyldopa for reducing the risk of severe hypertension (10 trials, 539 women, RR 0.75 (95 % CI 0.59 to 0.94); RD -0.08 (-0.14 to 0.02); NNT 12 (6 to 275)). There is no clear difference between any of the alternative drugs in the risk of developing proteinuria/pre-eclampsia. Other outcomes were only reported by a small proportion of studies, and there were no clear differences. AUTHORS' CONCLUSIONS It remains unclear whether antihypertensive drug therapy for mild to moderate hypertension during pregnancy is worthwhile.
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Affiliation(s)
- E Abalos
- Centro Rosarino de Estudios Perinatales, Pueyrredon 985, Rosario, Santa Fe, Argentina, 2000.
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Robins JB, Woodward M, Lowe G, McCaul P, Cheyne H, Walker JJ. First trimester maternal blood rheology and pregnancy induced hypertension. J OBSTET GYNAECOL 2005; 25:746-50. [PMID: 16368576 DOI: 10.1080/01443610500314637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This study evaluates the relationship between the first trimester assessment of maternal rheology and the subsequent development of pregnancy induced hypertension. This is a prospective observational study based in the Glasgow Royal Maternity Hospital, Scotland. From an original population of 744 consecutive antenatal attendees a total of 579 women were booked at less than 14 weeks' gestation. The main study group is a further subset comprising 251 primigravid women booking with a singleton pregnancy without essential hypertension. Previously published data from a group of non-pregnant women of similar age drawn from the same local community was used for external comparison. Blood samples were collected at the booking visit, from which fibrinogen, red cell aggregation, haematocrit and plasma, whole blood, relative and corrected viscosities were recorded. Information was obtained from the case notes in retrospect starting approximately 1 year after the first patients had first been recruited into the trial. The overall outcome of the pregnancies was noted with particular reference to pregnancy induced hypertension (PIH), birth weight, antepartum haemorrhage, pre-term labour, perinatal death, condition at delivery and neonatal complication. Our results show PIH is associated with a significantly raised mean blood viscosity and fibrinogen at time of booking. All significance disappears after adjustment for smoking, diastolic blood pressure and age. Viscosity is, however, only marginally non-significant (p = 0.07). In conclusion, blood rheology, in particular blood viscosity and fibrinogen, may play a predictive role in the development of pregnancy-induced hypertension. When combined with measurement of smoking and diastolic blood pressure at booking, these measurements could be used to calculate a risk score for the development of PIH, allowing targeting of antenatal care. Further data is required.
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Affiliation(s)
- J B Robins
- Glasgow Royal Maternity Hospital, Scotland, UK.
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Kametas NA, Krampl E, McAuliffe F, Rampling MW, Nicolaides KH. Pregnancy at high altitude: a hyperviscosity state. Acta Obstet Gynecol Scand 2004; 83:627-33. [PMID: 15225186 DOI: 10.1111/j.0001-6349.2004.00434.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Pregnancy at high altitude has been associated with intrauterine growth restriction and preeclampsia. These conditions, at sea level, have been linked to increased hematocrit and blood viscosity. The aim of this study was to investigate the effect of high altitude on maternal hemorheology. METHODS This was a cross-sectional study. We examined 94 pregnant women at 10-38 weeks of gestation resident at high altitude (4370 m above sea level) and 75 at sea level, and 24 and 17 nonpregnant women at each altitude, respectively. Blood and plasma viscosity, hematocrit, plasma fibrinogen, albumin and total protein concentrations were determined in blood samples obtained after an overnight period of fasting. RESULTS Pregnancy at high altitude, compared to sea level, is characterized by higher hematocrit, blood viscosity (at high shear rate), plasma viscosity, total protein and fibrinogen concentrations (25%, 38%, 7%, 13.3% and 25%, respectively) and 6% lower albumin concentration. Nonpregnant women at high altitude, compared to sea level, had higher hematocrits, blood viscosity, plasma viscosity, total protein and fibrinogen concentrations (25%, 55%, 18%, 26% and 98%, respectively) and 13% lower albumin concentration. CONCLUSION Pregnancy at high altitude compared to sea level is characterized by increased blood viscosity as a result of increased hematocrit and plasma viscosity.
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Affiliation(s)
- Nikos A Kametas
- Harris Birthright Research Center for Fetal Medicine, King's College Hospital, London, UK.
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Abalos E, Duley L, Steyn DW, Henderson-Smart DJ. Antihypertensive drug therapy for mild to moderate hypertension during pregnancy. Cochrane Database Syst Rev 2001:CD002252. [PMID: 11406040 DOI: 10.1002/14651858.cd002252] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Mild-moderate hypertension during pregnancy is common. Antihypertensive drugs are often used in the belief that lowering blood pressure will prevent progression to more severe disease, and thereby improve outcome. OBJECTIVES To assess the effects of antihypertensive drug treatments for women with mild to moderate hypertension during pregnancy. SEARCH STRATEGY Relevant trials were identified in the register of trials maintained by the Cochrane Pregnancy and Childbirth Group. In addition, the Cochrane Controlled Trial Register, MEDLINE, and EMBASE were searched. Date of last search: October 2000. SELECTION CRITERIA All randomised trials evaluating any antihypertensive drug treatment for mild to moderate hypertension during pregnancy, defined whenever possible as systolic blood pressure 140-169 mmHg and diastolic blood pressure 90-109 mmHg. Comparisons were of one or more antihypertensive drug(s) with placebo, with no antihypertensive drug, or with another antihypertensive drug, and where treatment was planned to continue for at least seven days. DATA COLLECTION AND ANALYSIS Data were extracted independently by two reviewers. MAIN RESULTS Overall, this review includes 40 studies (3797 women), 24 of which compared an antihypertensive drug with placebo/no antihypertensive drug (2815 women). There is a halving in the risk of developing severe hypertension associated with the use of antihypertensive drug(s) [17 trials, 2155 women; relative risk (RR) 0.52 (95% confidence interval (CI) 0.41 to 0.64); risk difference (RD) -0.09 (-0.12 to -0.06); number needed to treat (NNT) 12 (9 to 17)] but little evidence of a difference in the risk of pre-eclampsia [19 trials, 2402 women; RR 0.99 (0.84 to 1.18)]. Similarly, there is no clear effect on the risk of the baby dying [23 trials, 2727 women; RR 0.71(0.46 to 1.09)], preterm birth [12 trials, 1738 women; RR 0.98 (0.85 to 1.13)], or small for gestational age babies [17 trials, 2159 women; RR 1.13 (0.91 to 1.42)]. There were no clear differences in any other outcomes. Seventeen trials (1182 women) compared one antihypertensive drug with another. There is no clear difference between any of these drugs in the risk of developing severe hypertension, and proteinuria/pre-eclampsia. Other antihypertensive agents seem better than methyldopa for reducing the risk of the baby dying [14 trials, 1010 subjects, RR 0.49 (0.24 to 0.99); RD -0.02 (-0.04 to 0.00); NNT 45 (22 to 1341)]. Other outcomes were only reported by a small proportion of studies, and there were no clear differences. REVIEWER'S CONCLUSIONS It remains unclear whether antihypertensive drug therapy for mild-moderate hypertension during pregnancy is worthwhile.
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Affiliation(s)
- E Abalos
- Centro Rosarino de Estudios Perinatales, Pueyrredon 985, Rosario, Santa Fe, Argentina, 2000.
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Tranquilli AL, Garzetti GG, De Tommaso G, Boemi M, Lucino E, Fumelli P, Romanini C. Nifedipine treatment in preeclampsia reverts the increased erythrocyte aggregation to normal. Am J Obstet Gynecol 1992; 167:942-5. [PMID: 1415429 DOI: 10.1016/s0002-9378(12)80016-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVES Our objectives were to assess erythrocyte aggregation in hypertensive pregnancy and to evaluate the effect of the antihypertensive treatment on it. STUDY DESIGN The mean entity of erythrocyte aggregation was determined by an automatic aggregometer in 57 pregnant women: 20 normotensive, seven chronically hypertensive, 10 chronically hypertensive with superimposed preeclampsia, and 20 with preeclampsia. Ten of the latter were subsequently treated by 40 mg/day oral nifedipine; the other 10 by 400 mg/day oral labetalol, to keep diastolic blood pressure < 90 mm Hg. Also, patients with superimposed preeclampsia were treated with 40 mg/day oral nifedipine. RESULTS Erythrocyte aggregation was increased in all the hypertensive pregnant patients compared with the normotensive pregnant controls, regardless of both the onset (chronic or pregnancy-induced) of hypertension and the status of plasma macromolecules. Antihypertensive treatment with labetalol significantly reduced the aggregability of erythrocytes, whereas treatment with nifedipine reverted it to normal. CONCLUSIONS Increased erythrocyte aggregation may be due to either conformational changes of the membrane occurring during hypertension or a redistribution of the ionic charges on the two surfaces of the membrane. The effect of nifedipine by restoring the ionic charges may be due to this latter event.
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Affiliation(s)
- A L Tranquilli
- Department of Obstetrics and Gynecology, University of Ancona, Italy
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Huisman A, Aarnoudse JG, Heuvelmans JH, Goslinga H, Fidler V, Huisjes HJ, Zijlstra WG. Whole blood viscosity during normal pregnancy. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1987; 94:1143-9. [PMID: 3426986 DOI: 10.1111/j.1471-0528.1987.tb02313.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In a serial study the changes in whole blood viscosity at different shear rates and its major determinants were determined in 24 healthy women with normal pregnancies. Whole blood viscosity and plasma viscosity were measured with a rotational viscometer. Red cell aggregation was measured by syllectometry. During normal pregnancy we found a decrease in whole blood viscosity at all shear rates until 29 weeks gestation, followed by a smaller increase between 30 and 37 weeks, which was most pronounced at higher shear rates, especially in nulliparae. The changes in whole blood viscosity were to a great extent determined by the changes in haematocrit and plasma viscosity. Haematocrit was more important for whole blood viscosity at lower shear rates, while plasma viscosity had more influence on high shear blood viscosity. The continuous increase in red cell aggregation had no demonstrable influence on low shear blood viscosity as measured in vitro in a rotational viscometer.
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Affiliation(s)
- A Huisman
- Department of Obstetrics, University of Groningen, The Netherlands
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Abstract
Pregnancy is a hypervolaemic situation with early expanded plasma volume, a high cardiac output and a decrease in the vascular and rheological resistance. The increase in plasma volume correlates better with fetal size than maternal size. The hypervolaemic and vasodilated state that accompanies normal pregnancy results in a high flow in the uterine arteries. In contrast, patients with PIH (pregnancy-induced hypertension) or placental insufficiency may have a contracted plasma volume secondary to diffuse vasoconstriction. In spite of the intense vasospasm and hypovolaemia, pre-eclampsia has generally a cardiac output which may be equal, higher or lower compared with non-eclamptic pregnancy. Hypovolaemia is reflected in a higher haematocrit than normal. In the case of a hypovolaemic state, haemoconcentration is associated with high red cell aggregation. In fetal distress and severe PIH, the rheological status (haemoconcentration and elevated red cell aggregation) has a high predictive value for perinatal complications. In patients with severe PIH, erythrocyte filtration is impaired. The increased leukocyte count in patients with PIH may occlude small vessels and could be a factor impairing intervillous blood flow. The increased erythrocyte rigidity may result from a re-distribution of cellular calcium metabolism (Blaustein concept). We conclude that there is an optimal haematocrit during pregnancy between 30% and 38%. The presence of a high haematocrit and in addition elevated red cell aggregation should alert the physician to an increased risk of fetal compromise.
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Mayhew TM, Jackson MR, Haas JD. Microscopical morphology of the human placenta and its effects on oxygen diffusion: a morphometric model. Placenta 1986; 7:121-31. [PMID: 3725744 DOI: 10.1016/s0143-4004(86)80003-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A combination of stereological and physicochemical data was used to estimate the oxygen-diffusing capacity of the human term placenta. The effects on this morphometric diffusing capacity of isolated changes in placental structure were investigated by permitting volumes, surface areas and harmonic mean diffusion distances to deviate from normal baseline (term) values. Diffusion performance could be monitored effectively by estimating only three structural quantities. The most influential variable was the harmonic mean thickness of the villous membrane followed by the surface areas of villi and of fetal capillaries. Blood space volumes and plasma diffusion distances had negligible effects on diffusing capacity. Conclusions are discussed in the context of published findings on changes in placental anatomy which occur during gestation, abnormal pregnancies and pregnancies at high altitude.
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