The use of Doppler velocitnetry of the utnbilical artery before 24 weeks' gestation to screen for high-risk pregnancies

Objective. To describe the prevalence and natural history of absent end-diastolic velocities (AEDV) in the mnbilical artery of the fetus between 16 and 24 weeks' gestation, and to evaluate its role as a screening test.Design. Population-based descriptive study.Setting. Tygerberg Hospital, Tygerberg, South Africa. The hospital serves a population from the lower socio-economic bracket.Subjects. Doppler velocimetry was performed at routine ultrasound examinations for confirmation of gestational age in 496 women.Main outcome measures. The occurrence of perinatal death, small-for-gestational-age (SGA) babies and proteinuric hypertension.Results. Forty-four (8,9%) patients had AEDVs at the first examination, but AEDV persisted in only 1. In this case, severe proteinuric hypertension developed unexpectedly at 29 weeks' gestation and the fetus needed delivery because ofpersistent late decelerations of the fetal heart rate pattern. There was a significant association between the group with AEDV at first examination and the development of proteinuric hypertension (P <0,05), but no association with SGA babies. The association with proteinuric hypertension was too weak to be of clinical use.Conclusion. Doppler velocimetry of the mnbilical artery, performed along with routine ultrasound examination to confirm gestational age, is not of use as a screening test for identifYing highrisk pregnancies

Umbilical artery Doppler velocimetry in the prediction of intrapartum fetal compromise

CITATION: Howarth, G. R. et al. 1992. Umbilical artery Doppler velocimetry in the prediction of intrapartum fetal compromise. South African Medical Journal, 81:248-250.The original publication is available at http://www.samj.org.zaThe value of early intrapartum umbilical artery Doppler velocimetry in the prediction of fetal compromise was studied. One hundred patients were recruited into the study and fetal compromise was diagnosed by abnormal first- or second-stage fetal heart rate traces, a 5-minute Apgar score less than 7, or the development of hypoxic ischaemic encephalopathy. Fetal compromise developed in 30 patients. An umbilical artery resistance index (RI) of 0,66 or less did not predict fetal compromise (sensitivity 13%, specificity 89%, positive predictive value 25%, negative predictive value 70%). Since the mean umbilical artery RI was identical in the compromised and the noncompromised groups, we conclude that early intrapartum Doppler velocimetry is of very little clinical value in predicting fetal compromise at term.Publisher’s versio

Increased placental resistance and late decelerations associated with severe proteinuric hypertension predicts poor fetal outcome

CITATION: Pattinson, R. C. et al. 1989. Increased placental resistance and late decelerations associated with severe proteinuric hypertension predicts poor fetal outcome. South African Medical Journal, 75:211-214.The original publication is available at http://www.samj.org.zaThe flow velocity wave forms generated by Doppler ultrasound examination of the umbilical artery were correlated with feto-placental blood flow and numerically expressed as a ratio between the systolic (A) and the end-diastolic point (B). The technique is non-invasive and simple to perform. A cohort analytical study was done to see whether useful information could be obtained from the A/B ratio that could help in the management of patients with severe proteinuric hypertension. Fifty patients with severe proteinuric hypertension at less than 34 weeks' gestation were studied and serial Doppler ultrasound examinations of the umbilical artery were performed. No ultrasound results were made available to the clinician. An A/B ratio of 6 or greater was regarded as increased. Twenty-eight of the patients had an increased A/B ratio; in this group these 14 infants were small for gestational age, 14 developed late decelerations and there were 12 perinatal deaths. The remaining 22 patients had an A/B ratio of less than 6 and only 3 produced infants which were small for gestational age; 2 fetuses developed late decelerations and there was 1 perinatal death. A significant difference was found between the two groups in respect of these results. The group with an abnormal A/B ratio also experienced more neonatal morbidity. The A/B ratio of the umbilical artery wave form may assist in planning delivery of patients with severe proteinuric hypertension more accurately.Publisher’s versio

Smoking and drinking habits of women in subsequent pregnancies after specific advice about the dangers of these exposures during pregnancy

Background. Although women are informed about the dangers of drinking and smoking during pregnancy when they book for antenatal care, it is uncertain whether this advice is accepted, or whether attempts are made to apply it in subsequent pregnancies.Objectives. To assess how pregnant women respond to the advice to refrain from smoking and drinking during pregnancy in subsequent pregnancies.Methods. Research staff were trained to obtain accurate prospective information on smoking and drinking during pregnancy in a prospective study, using well-standardised methods. Care was taken to inform participants about the dangers of smoking and drinking during pregnancy. They were also given pamphlets on these dangers in their own language and a list of telephone numbers where they could find help to quit should they need it. This information was repeated at subsequent study visits (ranging from 1 to 3, depending on the gestational age at which they enrolled). Gestational age was determined by early ultrasound. Z-scores of birthweight for gestational age were determined according to the INTERGROWTH-21st study. Pregnancy outcomes of women who enrolled twice (n=888) or three times (n=77) in the Safe Passage Study were compared with those of women in the first enrolment (n=889).Results. The proportion of drinkers did not change significantly (p=0.058) from the first to the second and third enrolments (63.8%, 59.0% and 54.6%, respectively). A similar trend was found for smokers (73.3%, 72.2% and 68.4%, respectively). Cannabis use was reported by 15.1%, 9.7% and 12.0% (p<0.005) of women, respectively, and use of methamphetamine by 10.1%, 6.6% and 12.7% (p<0.005). There was an increase in the rate of preterm births from 15.5% to 17.5% and 24.7%, respectively, but the increase was not significant. Although mean birthweight was lower in the third enrolment compared with the second, the difference was not significant. The z-score of birthweight for gestational age was significantly lower in the second enrolment compared with the first.Conclusions. Detailed information on the adverse effects of smoking and drinking during pregnancy was not effective in the population studied. Other methods to reduce or stop these toxic exposures should therefore be investigated. A short inter-pregnancy interval, as demonstrated by three enrolments in 7.5 years, is associated with preterm labour and fetal growth restriction, and is probably indicative of the role played by confounders such as poor socioeconomic conditions and drug exposure during pregnancy

The association between preterm labour perinatal mortality and infant death during the first year in Bishop Lavis Cape Town South Africa

Background. We present further analyses from the Safe Passage Study, where the effect of alcohol exposure during pregnancy on sudden infant death syndrome and stillbirth was investigated.Objectives. To describe pregnancy and neonatal outcome in a large prospective study where information on the outcome of pregnancy was known in >98.3% of participants and ultrasound was used to determine gestational age (GA).Methods. As part of the Safe Passage Study of the PASS Network in Cape Town, South Africa, the outcomes of 6 866 singleton pregnancies were prospectively followed from recruitment in early pregnancy until the infant was 12 months old to assess pregnancy outcome. Fetal growth was assessed by z-scores of the birth weight, and GA at birth was derived from early ultrasound assessments. The effects of fetal growth restriction and preterm delivery on pregnancy outcome were determined.Results. There were 66 miscarriages, 107 stillbirths at ≥22 weeks’ gestation, 66 stillbirths at ≥28 weeks’ gestation, 29 and 18 neonatal deaths at ≥22 and ≥28 weeks’ gestation, respectively, and 54 post-neonatal deaths (28 days - 12 months). The miscarriage rate was 9.6/1 000 and the infant mortality rate 12.4/1 000. Of the births, 13.8% were preterm. For deliveries at ≥22 and ≥28 weeks, the stillbirth rates were 15.7 and 9.8/1 000 deliveries, respectively. For deliveries at ≥22 and ≥28 weeks, the neonatal death rates were 4.3 and 2.7/1 000 live births, respectively. For these pregnancies the perinatal mortality rates were 20.0/1 000 (≥22 weeks) and 12.5/1 000 (≥28 weeks), respectively. Only 15.9% of stillbirths occurred during labour (in 15.9% of cases it was uncertain whether death had occurred during labour). In the majority of cases (68.2%) fetal death occurred before labour, and 82.2% of stillbirths and 62.1% of neonatal deaths occurred in deliveries before 37 weeks. Including the miscarriages, stillbirths and infant deaths, there were 256 pregnancy losses; 77.3% were associated with deliveries before 37 weeks. Only 1.8% of all the women were HIV-positive, whereas the HIV-positive rate was 3.7% among those who had stillbirths. Birth weight was below the 10th centile in 25.6% of neonatal and post-neonatal deaths compared with 17.7% of survivors.Conclusions. Preterm birth and fetal growth restriction play significant roles in fetal, neonatal and infant losses.Â

Making space for drones: the contested reregulation of airspace in Tanzania and Rwanda

In this paper we examine how certain African countries have become testbeds for new forms of drone infrastructure and regulation, driven by the overlapping interests of governments, drone operators, and international development agencies. In particular we explore the factors that have led to the development of an advanced medical delivery network in Rwanda and contrast that with the closing down of airspace for drones in Tanzania. The paper makes a distinctive contribution to research on the ongoing constitution and enclosure of dronespace as a sphere of commercial and governmental activity

Diagnostic performance of dobutamine stress echocardiography: A South African experience

Background. Dobutamine stress echocardiography (DSE) is a well-established modality for the diagnosis of coronary artery disease, but there are no reported diagnostic data in southern Africa. Objectives. To compare the safety, sensitivity and specificity of a South African (SA) DSE programme with larger, international series. Methods. All patients undergoing DSE from 2019 to 2021 at a single SA centre were included. A new wall motion abnormality (≥2 segments) signified inducible ischaemia. Results. A total of 106 patients (mean (standard deviation) age 61 (11) years, 68% male) were analysed. Six patients (6%) experienced chest pain during DSE and 4 (4%) developed an atrial arrhythmia. The sensitivity and specificity for epicardial coronary stenosis were 77% and 74%, respectively, changing to 82% and 72% when excluding those who had previous coronary artery bypass surgery. Conclusion. The sensitivity, specificity and safety of an SA DSE programme were comparable to international series. A DSE programme is feasible in a resource-constrained environment

The association between preterm labour, perinatal mortality and infant death (during the first year) in Bishop Lavis, Cape Town, South Africa

Background. We present further analyses from the Safe Passage Study, where the effect of alcohol exposure during pregnancy on sudden infant death syndrome and stillbirth was investigated.Objectives. To describe pregnancy and neonatal outcome in a large prospective study where information on the outcome of pregnancy was known in >98.3% of participants and ultrasound was used to determine gestational age (GA).Methods. As part of the Safe Passage Study of the PASS Network in Cape Town, South Africa, the outcomes of 6 866 singleton pregnancies were prospectively followed from recruitment in early pregnancy until the infant was 12 months old to assess pregnancy outcome. Fetal growth was assessed by z-scores of the birth weight, and GA at birth was derived from early ultrasound assessments. The effects of fetal growth restriction and preterm delivery on pregnancy outcome were determined.Results. There were 66 miscarriages, 107 stillbirths at ≥22 weeks’ gestation, 66 stillbirths at ≥28 weeks’ gestation, 29 and 18 neonatal deaths at ≥22 and ≥28 weeks’ gestation, respectively, and 54 post-neonatal deaths (28 days - 12 months). The miscarriage rate was 9.6/1 000 and the infant mortality rate 12.4/1 000. Of the births, 13.8% were preterm. For deliveries at ≥22 and ≥28 weeks, the stillbirth rates were 15.7 and 9.8/1 000 deliveries, respectively. For deliveries at ≥22 and ≥28 weeks, the neonatal death rates were 4.3 and 2.7/1 000 live births, respectively. For these pregnancies the perinatal mortality rates were 20.0/1 000 (≥22 weeks) and 12.5/1 000 (≥28 weeks), respectively. Only 15.9% of stillbirths occurred during labour (in 15.9% of cases it was uncertain whether death had occurred during labour). In the majority of cases (68.2%) fetal death occurred before labour, and 82.2% of stillbirths and 62.1% of neonatal deaths occurred in deliveries before 37 weeks. Including the miscarriages, stillbirths and infant deaths, there were 256 pregnancy losses; 77.3% were associated with deliveries before 37 weeks. Only 1.8% of all the women were HIV-positive, whereas the HIV-positive rate was 3.7% among those who had stillbirths. Birth weight was below the 10th centile in 25.6% of neonatal and post-neonatal deaths compared with 17.7% of survivors.Conclusions. Preterm birth and fetal growth restriction play significant roles in fetal, neonatal and infant losses.

On handling urban informality in southern Africa

In this article I reconsider the handling of urban informality by urban planning and management systems in southern Africa. I argue that authorities have a fetish about formality and that this is fuelled by an obsession with urban modernity. I stress that the desired city, largely inspired by Western notions of modernity, has not been and cannot be realized. Using illustrative cases of top–down interventions, I highlight and interrogate three strategies that authorities have deployed to handle informality in an effort to create or defend the modern city. I suggest that the fetish is built upon a desire for an urban modernity based on a concept of formal order that the authorities believe cannot coexist with the “disorder” and spatial “unruliness” of informality. I question the authorities' conviction that informality is an abomination that needs to be “converted”, dislocated or annihilated. I conclude that the very configuration of urban governance and socio-economic systems in the region, like the rest of sub-Saharan Africa, renders informality inevitable and its eradication impossible