Valerie Vannevel
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Valerie Vannevel has a total of 68 co-authors. Here are the top co-authors by number of shared publications:
- Robert Pattinson
South African Medical Research Council Maternal and Infant Health Care Strategies Unit, Faculty of Health Sciences, University of Pretoria, South Africa; Department of Obstetrics and Gynaecology, Faculty of Health Sciences, University of Pretoria, South Africa
2 shared publications - Alain Bernard Labrique
Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
1 shared publication Alfred Osoti
Department of Obstetrics and Gynaecology, University of Nairobi, Nairobi, Kenya
1 shared publication- Alimuddin Zumla
Center for Clinical Microbiology, Institute of Infection, Immunity and Transplantation, University College London, London, UK; NIHR Biomedical Research Centre, University College London Hospitals NHS Foundation Trust, London, UK
1 shared publication Avinash Kavi
Women’s and Children’s Health Research Unit, Jawaharlal Nehru Medical College, KLE Academy of Higher Education and Research, Belgaum, Karnataka, India
1 shared publication- Birhanu Teshome Ayele
Division of Epidemiology and Biostatistics, Department of Global Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
1 shared publication
Latest Publications
- Open Access
- 17 April 2023
- Published by Springer Nature in npj Digital Medicine
- Vol. 6 (1) , 1-9
Accuracy of a smartphone application for blood pressure estimation in Bangladesh, South Africa, and Tanzania
Undetected and unmonitored hypertension carries substantial mortality and morbidity, especially during pregnancy. We assessed the accuracy of OptiBPTM, a smartphone application for estimating blood pressure (BP), across diverse settings. The study was conducted in community settings: Gaibandha, Bangladesh and Ifakara, Tanzania for general populations, and Kalafong Provincial Tertiary Hospital, South Africa for pregnant populations. Based on guidance from the International Organization for Standardization (ISO) 81,060–2:2018 for non-invasive BP devices and global consensus statement, we compared BP measurements taken by two independent trained nurses on a standard auscultatory cuff to the BP measurements taken by a research version of OptiBPTM called CamBP. For ISO criterion 1, the mean error was 0.5 ± 5.8 mm Hg for the systolic blood pressure (SBP) and 0.1 ± 3.9 mmHg for the diastolic blood pressure (DBP) in South Africa; 0.8 ± 7.0 mmHg for the SBP and −0.4 ± 4.0 mmHg for the DBP in Tanzania; 3.3 ± 7.4 mmHg for the SBP and −0.4 ± 4.3 mmHg for the DBP in Bangladesh. For ISO criterion 2, the average standard deviation of the mean error per subject was 4.9 mmHg for the SBP and 3.4 mmHg for the DBP in South Africa; 6.3 mmHg for the SBP and 3.6 mmHg for the DBP in Tanzania; 6.4 mmHg for the SBP and 3.8 mmHg for the DBP in Bangladesh. OptiBPTM demonstrated accuracy against ISO standards in study populations, including pregnant populations, except in Bangladesh for SBP (criterion 2). Further research is needed to improve performance across different populations and integration within health systems.
- 17 April 2023
- Published by Springer Nature in npj Digital Medicine
- Vol. 6 (1) , 1-9
Open AccessAccuracy of a smartphone application for blood pressure estimation in Bangladesh, South Africa, and Tanzania
Undetected and unmonitored hypertension carries substantial mortality and morbidity, especially during pregnancy. We assessed the accuracy of OptiBPTM, a smartphone application for estimating blood pressure (BP), across diverse settings. The study was conducted in community settings: Gaibandha, Bangladesh and Ifakara, Tanzania for general populations, and Kalafong Provincial Tertiary Hospital, South Africa for pregnant populations. Based on guidance from the International Organization for Standardization (ISO) 81,060–2:2018 for non-invasive BP devices and global consensus statement, we compared BP measurements taken by two independent trained nurses on a standard auscultatory cuff to the BP measurements taken by a research version of OptiBPTM called CamBP. For ISO criterion 1, the mean error was 0.5 ± 5.8 mm Hg for the systolic blood pressure (SBP) and 0.1 ± 3.9 mmHg for the diastolic blood pressure (DBP) in South Africa; 0.8 ± 7.0 mmHg for the SBP and −0.4 ± 4.0 mmHg for the DBP in Tanzania; 3.3 ± 7.4 mmHg for the SBP and −0.4 ± 4.3 mmHg for the DBP in Bangladesh. For ISO criterion 2, the average standard deviation of the mean error per subject was 4.9 mmHg for the SBP and 3.4 mmHg for the DBP in South Africa; 6.3 mmHg for the SBP and 3.6 mmHg for the DBP in Tanzania; 6.4 mmHg for the SBP and 3.8 mmHg for the DBP in Bangladesh. OptiBPTM demonstrated accuracy against ISO standards in study populations, including pregnant populations, except in Bangladesh for SBP (criterion 2). Further research is needed to improve performance across different populations and integration within health systems.
- Open Access
Early Childhood Growth Parameters in South African Children with Exposure to Maternal HIV Infection and Placental Insufficiency
Maternal HIV exposure and intrauterine growth restriction (IUGR) due to placental insufficiency both carry major risks to early child growth. We compared the growth outcomes of children aged 18 months who had abnormal umbilical artery resistance indices (UmA-RI), as a marker of placental insufficiency, with a comparator group of children with normal UmA-RI during pregnancy, as mediated by maternal HIV infection. The cross-sectional study included 271 children, grouped into four subgroups based on HIV exposure and history of normal/abnormal UmA-RI, using available pregnancy and birth information. Standard procedures were followed to collect anthropometric data, and z-scores computed as per World Health Organization growth standards. Lower length-for-age z-scores (LAZ) were observed in children who were HIV-exposed-uninfected (CHEU) (−0.71 ± 1.23; p = 0.004) and who had abnormal UmA-RI findings (−0.68 ± 1.53; p < 0.001). CHEU with abnormal UmA-RI had lower LAZ (−1.3 ± 1.3; p < 0.001) and weight-for-age z-scores (WAZ) (−0.64 ± 0.92; p = 0.014) compared to the control group. The prevalence of stunting was 40.0% in CHEU with abnormal UmA-RI and 16.0% in CHEU with normal UmA-RI (p < 0.001; p = 0.016, respectively). In conclusion, maternal HIV exposure and placental insufficiency are independent risk factors for childhood stunting, with this risk potentiated when these two risk factors overlap.
Open AccessEarly Childhood Growth Parameters in South African Children with Exposure to Maternal HIV Infection and Placental Insufficiency
Maternal HIV exposure and intrauterine growth restriction (IUGR) due to placental insufficiency both carry major risks to early child growth. We compared the growth outcomes of children aged 18 months who had abnormal umbilical artery resistance indices (UmA-RI), as a marker of placental insufficiency, with a comparator group of children with normal UmA-RI during pregnancy, as mediated by maternal HIV infection. The cross-sectional study included 271 children, grouped into four subgroups based on HIV exposure and history of normal/abnormal UmA-RI, using available pregnancy and birth information. Standard procedures were followed to collect anthropometric data, and z-scores computed as per World Health Organization growth standards. Lower length-for-age z-scores (LAZ) were observed in children who were HIV-exposed-uninfected (CHEU) (−0.71 ± 1.23; p = 0.004) and who had abnormal UmA-RI findings (−0.68 ± 1.53; p < 0.001). CHEU with abnormal UmA-RI had lower LAZ (−1.3 ± 1.3; p < 0.001) and weight-for-age z-scores (WAZ) (−0.64 ± 0.92; p = 0.014) compared to the control group. The prevalence of stunting was 40.0% in CHEU with abnormal UmA-RI and 16.0% in CHEU with normal UmA-RI (p < 0.001; p = 0.016, respectively). In conclusion, maternal HIV exposure and placental insufficiency are independent risk factors for childhood stunting, with this risk potentiated when these two risk factors overlap.
- Open Access
Antenatal Doppler screening for fetuses at risk of adverse outcomes: a multicountry cohort study of the prevalence of abnormal resistance index in low-risk pregnant women
Introduction Few interventions exist to address the high burden of stillbirths in apparently healthy pregnant women in low- and middle-income countries (LMICs). To establish whether a trial on the impact of routine Doppler screening in a low-risk obstetric population is warranted, we determined the prevalence of abnormal fetal umbilical artery resistance indices among low-risk pregnant women using a low-cost Doppler device in five LMICs. Methods We conducted a multicentre, prospective cohort study in Ghana, India, Kenya, Rwanda and South Africa. Trained nurses or midwives performed a single, continuous-wave Doppler screening using the Umbiflow device for low-risk pregnant women (according to local guidelines) between 28 and 34 weeks’ gestation. We assessed the prevalence of abnormal (raised) resistance index (RI), including absent end diastolic flow (AEDF), and compared pregnancy and health service utilisation outcomes between women with abnormal RI versus those with normal RI. Results Of 7151 women screened, 495 (6.9%) had an abnormal RI, including 14 (0.2%) with AEDF. Caesarean section (40.8% vs 28.1%), labour induction (20.5% vs 9.0%) and low birth weight (Conclusion A single Doppler screening of low-risk pregnant women in LMICs using the Umbiflow device can detect a large number of fetuses at risk of growth restriction and consequent adverse perinatal outcomes. Many perinatal deaths could potentially be averted with appropriate intervention strategies. Trial registration number CTRI/2018/07/01486.
Open AccessAntenatal Doppler screening for fetuses at risk of adverse outcomes: a multicountry cohort study of the prevalence of abnormal resistance index in low-risk pregnant women
Introduction Few interventions exist to address the high burden of stillbirths in apparently healthy pregnant women in low- and middle-income countries (LMICs). To establish whether a trial on the impact of routine Doppler screening in a low-risk obstetric population is warranted, we determined the prevalence of abnormal fetal umbilical artery resistance indices among low-risk pregnant women using a low-cost Doppler device in five LMICs. Methods We conducted a multicentre, prospective cohort study in Ghana, India, Kenya, Rwanda and South Africa. Trained nurses or midwives performed a single, continuous-wave Doppler screening using the Umbiflow device for low-risk pregnant women (according to local guidelines) between 28 and 34 weeks’ gestation. We assessed the prevalence of abnormal (raised) resistance index (RI), including absent end diastolic flow (AEDF), and compared pregnancy and health service utilisation outcomes between women with abnormal RI versus those with normal RI. Results Of 7151 women screened, 495 (6.9%) had an abnormal RI, including 14 (0.2%) with AEDF. Caesarean section (40.8% vs 28.1%), labour induction (20.5% vs 9.0%) and low birth weight (Conclusion A single Doppler screening of low-risk pregnant women in LMICs using the Umbiflow device can detect a large number of fetuses at risk of growth restriction and consequent adverse perinatal outcomes. Many perinatal deaths could potentially be averted with appropriate intervention strategies. Trial registration number CTRI/2018/07/01486.
- Open Access
- 28 December 2020
- Published by American Society of Tropical Medicine and Hygiene in The American Journal of Tropical Medicine and Hygiene
- Vol. 104 (2) , 461-465
Effect of SARS-CoV-2 Infection in Pregnancy on Maternal and Neonatal Outcomes in Africa: An AFREhealth Call for Evidence through Multicountry Research Collaboration
In the African context, there is a paucity of data on SARS-CoV-2 infection and associated COVID-19 in pregnancy. Given the endemicity of infections such as malaria, HIV, and tuberculosis (TB) in sub-Saharan Africa (SSA), it is important to evaluate coinfections with SARS-CoV-2 and their impact on maternal/infant outcomes. Robust research is critically needed to evaluate the effects of the added burden of COVID-19 in pregnancy, to help develop evidence-based policies toward improving maternal and infant outcomes. In this perspective, we briefly review current knowledge on the clinical features of COVID-19 in pregnancy; the risks of preterm birth and cesarean delivery secondary to comorbid severity; the effects of maternal SARS-CoV-2 infection on the fetus/neonate; and in utero mother-to-child SARS-CoV-2 transmission. We further highlight the need to conduct multicountry surveillance as well as retrospective and prospective cohort studies across SSA. This will enable assessments of SARS-CoV-2 burden among pregnant African women and improve the understanding of the spectrum of COVID-19 manifestations in this population, which may be living with or without HIV, TB, and/or other coinfections/comorbidities. In addition, multicountry studies will allow a better understanding of risk factors and outcomes to be compared across countries and subregions. Such an approach will encourage and strengthen much-needed intra-African, south-to-south multidisciplinary and interprofessional research collaborations. The African Forum for Research and Education in Health’s COVID-19 Research Working Group has embarked upon such a collaboration across Western, Central, Eastern and Southern Africa.
- 28 December 2020
- Published by American Society of Tropical Medicine and Hygiene in The American Journal of Tropical Medicine and Hygiene
- Vol. 104 (2) , 461-465
Open AccessEffect of SARS-CoV-2 Infection in Pregnancy on Maternal and Neonatal Outcomes in Africa: An AFREhealth Call for Evidence through Multicountry Research Collaboration
In the African context, there is a paucity of data on SARS-CoV-2 infection and associated COVID-19 in pregnancy. Given the endemicity of infections such as malaria, HIV, and tuberculosis (TB) in sub-Saharan Africa (SSA), it is important to evaluate coinfections with SARS-CoV-2 and their impact on maternal/infant outcomes. Robust research is critically needed to evaluate the effects of the added burden of COVID-19 in pregnancy, to help develop evidence-based policies toward improving maternal and infant outcomes. In this perspective, we briefly review current knowledge on the clinical features of COVID-19 in pregnancy; the risks of preterm birth and cesarean delivery secondary to comorbid severity; the effects of maternal SARS-CoV-2 infection on the fetus/neonate; and in utero mother-to-child SARS-CoV-2 transmission. We further highlight the need to conduct multicountry surveillance as well as retrospective and prospective cohort studies across SSA. This will enable assessments of SARS-CoV-2 burden among pregnant African women and improve the understanding of the spectrum of COVID-19 manifestations in this population, which may be living with or without HIV, TB, and/or other coinfections/comorbidities. In addition, multicountry studies will allow a better understanding of risk factors and outcomes to be compared across countries and subregions. Such an approach will encourage and strengthen much-needed intra-African, south-to-south multidisciplinary and interprofessional research collaborations. The African Forum for Research and Education in Health’s COVID-19 Research Working Group has embarked upon such a collaboration across Western, Central, Eastern and Southern Africa.
- Open Access
- 5 December 2019
- Published by South African Medical Association NPC in South African Medical Journal
- Vol. 109 (11b) , 15-19
Challenges to improve antenatal and intrapartum care in South Africa
The major causes of maternal and perinatal deaths have been well described in South Africa. These causes are related to HIV infection, placental insufficiency and intrapartum asphyxia. The health system failures that most commonly lead to preventable mortality are related to managing hypertensive disorders in pregnancy (HDP), detecting fetal growth restriction antenatally and managing labour effectively by providing caesarean delivery to those who need it and avoiding it in those who do not. Improving antenatal and intrapartum care are vital aspects in efforts to improve survival, but to achieve this the following challenges need to be overcome: managing the increased antenatal care contacts needed to detect HDP creating a next level of expertise, and access for women to high-risk care creating the environment for respectful care and companionship in labour managing labour as physiologically as possible detecting and managing placental insufficiency. This article provides some exciting solutions to these health system barriers.
- 5 December 2019
- Published by South African Medical Association NPC in South African Medical Journal
- Vol. 109 (11b) , 15-19
Open AccessChallenges to improve antenatal and intrapartum care in South Africa
The major causes of maternal and perinatal deaths have been well described in South Africa. These causes are related to HIV infection, placental insufficiency and intrapartum asphyxia. The health system failures that most commonly lead to preventable mortality are related to managing hypertensive disorders in pregnancy (HDP), detecting fetal growth restriction antenatally and managing labour effectively by providing caesarean delivery to those who need it and avoiding it in those who do not. Improving antenatal and intrapartum care are vital aspects in efforts to improve survival, but to achieve this the following challenges need to be overcome: managing the increased antenatal care contacts needed to detect HDP creating a next level of expertise, and access for women to high-risk care creating the environment for respectful care and companionship in labour managing labour as physiologically as possible detecting and managing placental insufficiency. This article provides some exciting solutions to these health system barriers.
- 1 April 2019
- Published by Elsevier in Best Practice & Research Clinical Obstetrics & Gynaecology
- Vol. 56, 107-113
Global perspectives on operative vaginal deliveries
- 1 April 2019
- Published by Elsevier in Best Practice & Research Clinical Obstetrics & Gynaecology
- Vol. 56, 107-113
Global perspectives on operative vaginal deliveries