published_or_final_version / Obstetrics and Gynaecology / Master / Master of Medical Sciences

M.Tech. / It is difficult to manage a pregnancy when fetal age, health status or potential pregnancy risks are not known. The aim of this study was to assess the impact of routine ultrasound screening as compared to selective use of ultrasound in the mid-trimester of pregnancy, on women using South African government health services. The three objectives investigated included assessment of the availability of reliable menstrual histories in the study population, the influence of ultrasound dating on obstetric management and the effect of ultrasound on pregnancy outcome due to the early detection of high risk pregnancies. A cluster randomised trial of 962 women was performed to test the hypothesis that midtrimester routine ultrasound screening in low risk pregnancies would result in improved antenatal care and perinatal outcome. Groups of eligible pregnant women were randomly selected to have either a routine scan followed by normal antenatal care or routine antenatal care which only allows for the selective use of ultrasound, in line with South African Antenatal Care Policy. Statistical analysis of the results confirmed that ultrasound dating is a more accurate predictor of the expected date of delivery when compared to other dating methods. Improved pregnancy dating resulted in a significant reduction in induction of labour for post-term pregnancy in the ultrasound screening group, suggesting a positive effect of ultrasound screening on obstetric management. No improvement was demonstrated in perinatal morbidity or mortality. The early detection of anomalous fetuses only led to one therapeutic abortion. The study did not possess the statistical power to demonstrate improved outcomes when multiple pregnancies were detected early in pregnancy. Currently there appears to be no urgent need to implement a routine antenatal screening programme in the Gauteng public health sector. In view of the fact that a third of the participants indicated that they were unsure of menstrual dates, and one third of the participants in the ultrasound screening group presented with an unreliable menstrual history, it is proposed that unsure dates be considered as a valid indication for the selective use of ultrasound in mid-trimester pregnancy.

published_or_final_version / abstract / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

published_or_final_version / Obstetrics and Gynaecology / Master / Master of Philosophy

published_or_final_version / Obstetrics and Gynaecology / Master / Master of Philosophy

Homozygous α0-thalassemia is a serious autosomal recessive disorder with poor fetal outcome and severe maternal complications. Conventionally, prenatal diagnosis is performed by an invasive test. A non-invasive approach using serial ultrasonography can effectively reduce the need for invasive tests in unaffected pregnancies. For two-dimensional ultrasound prediction, a total of 777 at-risk fetuses were studied from 12 to 20 weeks between 1995 and 2006. At 12–15 weeks’ gestation, the highest sensitivity (98.3%) was achieved by the combination of fetal cardiothoracic ratio (CTR) and/or middle cerebral artery peak systolic velocity (MCA-PSV) at a false-positive rate of 15.8%. At 16–20 weeks’ gestation, the sensitivity of CTR was 100.0%, but the false-positive rate was 5.2%. In contrast, the false-positive rate of MCA-PSV alone was 1.4% and that of the combination of CTR and MCA-PSV was 0%, although their sensitivities were less than 65%. In a cross-sectional retrospective study of 546 samples at-risk and control (268 fetal and 278 neonatal cord blood), the degree of anemia was only mild in 27.5% of the affected fetuses (see chapter 3 for definition of mild anemia). Because MCA-PSV is not very predictive of mild anemia, this may be one of the reasons why MCA-PSV is not very sensitive in predicting an affected pregnancy. A total of 832 at-risk pregnancies were studied using same noninvasive approach at Maternal and Neonatal Hospital of Guangzhou (MNH) and Tsan Yuk Hospital (TYH). The overall sensitivity and specificity of the noninvasive approach was 100% and 95.6% respectively. At MNH, the need for an invasive test was reduced by 78.6%, and all the affected pregnancies were diagnosed before 24 weeks’ gestation. After adequate training and monitoring the quality of the subsequent ultrasound examinations, the results achieved at MNH were comparable to TYH, with at-risk pregnancies including the affected ones being seen at a more advanced gestation at MNH. In a retrospective review of 361 women at risk of carrying an affected fetus, 311 (86.2%) opted for the non-invasive approach using CTR and/or placenta. The cost saving of this non-invasive approach was relatively small (HK$ 2,651) in comparison to the cost of the whole prenatal screening program. On the other hand, the non-invasive approach was more expensive than the direct invasive approach for low MCV couples, as well as couples discordant for α-thalassemia and β-thalassemia. ages. These results support the adoption of non-invasive approach in which routine invasive test or karyotyping is no longer performed. A total of 106 at-risk pregnancies and normal controls were prospectively studied using three-dimensional ultrasonography. Placental volume (PV) at 11-14 weeks, and PV/CRL quotient at 9-14 weeks’ gestation of affected pregnancies were significantly greater than unaffected pregnancies (P<0.05). Using a cut-off point of 1.2ml/mm for PV/CRL quotient to predict an affected pregnancy, the sensitivity, and specificity was 96.2%, and 100.0% respectively. / published_or_final_version / Obstetrics and Gynaecology / Master / Doctor of Medicine

published_or_final_version / Medicine / Master / Doctor of Medicine

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Thesis (MTech (Radiography))--Cape Peninsula University of Technology, 2006 / A prospective cohort study was done on Human Immunodeficiency Virus (HIV) infected and uninfected women attending Khayelitsha Midwifery Obstetric Unit (MOU) and Gugulethu MOU from June 2003 to December 2004, primarily to establish whether there is an association between HIV infection and Intra-uterine growth restriction (lUGR). B-Mode real time ultrasound imaging was used to monitor fetal growth from ±22 weeks to 36 weeks gestational age. Birth weight, gestational age at delivery, gender, placental weight, and maternal complications were also included. Maternal factors considered included age, weight parity, singleton versus multiple pregnancy, previous IUGR or preterm delivery, previous fetal abnormality, social habits viz. cigarette smoking, alcohol and drug use, and vascular disease viz. Diabetes, hypertension, renal disease, cardiac disease and collagen disease. A secondary objective was to establish whether the CD4 T-lymphocyte count possibly modulated the presence of IUGR. All HIV infected women were given antiretroviral therapy according to the standard Protocol of the Provincial Government of Western Cape (2002). The research questions were: • Does maternal HIV infection increase the risk of intrauterine growth restriction and associated preterm delivery? • Does the immune status of (CD4 T-lymphocyte count) of HIV infected pregnant women modulate fetal growth? The primary objective of this study was to establish whether there is an association between HIV infection and IUGR, and hence that HIV infection leads to an adverse perinatal outcome. Ultrasound was used as a diagnostic tool to establish normal or abnormal fetal growth patterns. Anecdotal reports from health workers in the obstetric field suggested that IUGR and preterm delivery may be associated with low birth weight infants in HIV infected pregnant women. However, preterm delivery is associated with various other factors including low socio-economic status (poor nutrition), cigarette smoking, drug and alcohol abuse, previous history of preterm delivery, over distention of the uterus (hydramnios, multiple gestation), premature rupture of membranes, cervical incompetence, vaginal infections (bacterial vaginosis) and maternal disease e.g. hypertension, heart disease (Lizzi, 1993: Symmonds, 1992; Odendaal et aI, 2002). HIV is now thought to be an added factor. Afier doing a systematic review and meta-analysis of 31 studies, Brocklehurst and French (1998) reported that there is an association (although not strong) between HIV infection and adverse perinatal outcome in developed countries; but in developing countries, there is an increased risk of infant death. By excluding or controlling for confounding variables that could affect fetal growth, this study aimed to determine whether there is a significant association between HIV and fetal growth by comparing fetal growth in HIV infected and uninfected women from midsecond trimester to the time of delivery. A secondary objective was to establish whether there is an association between the immune status (CD4 T-lymphocyte count) of the mother and IUGR. The immune status of the mother is probably one of the most important factors affecting the fetus and perinatal outcome. As the mother's viral load increases, her immune system is increasingly compromised, resulting in the occurrence of HIV-related diseases, and a concurrent increase in fetal complications. In this study a CD4 T-lymphocyte count was used to assess the level of immunodeficiency of all the HIV infected participants. Ideally the test should have been done each time the participant was scanned so that the CD4 T-lymphoc)1e count could be monitored simultaneously with the fetal growth parameters, however due to financial constraints and ethical considerations, one test was done on each HIV infected women. This study was based at two MOU's where different antiretroviral therapy (ARVT) regimens were used. The one MOU offered Zidovudine (ZDV) to mothers from 34 weeks gestation to the onset of labour, and the other MOU offered Nevirapine (NVP) as a single dose to the mother at the onset of labour and to the neonate within 72 hours of birth (Provincial Government Western Cape, 2002). This presented an opportunity to compare two groups of HIV infected women on different regimes. The intention was to establish whether ZDV had an adverse effect on fetal growth and resulted in low birth weight. However, 6 months after the study started a revised Prevention of Mother to Child Transmission (PMTCT) Protocol was implemented where women at both MOU's received the same ARVT i.e. ZDV and NVP. This objective was therefore abandoned due to a change in the PMTCT Protocol in the Western Cape. The study was based at two Midwife Obstetric Units (MOU) in the Western Cape where the prevalence of HIV in pregnant women is relatively high i.e. 20 - 24 % (Mother-to-child transmission Monitoring Team, 2001), viz. Gugulethu MOU and Khayelitsha MOU. A prospective cohort study was done with the intention of recruiting a sample of 400 pregnant women, 200 HIV infected and 200 uninfected. The actual sample size was 415. The study group was 194 HIV infected women and the control group was 221 uninfected women. Confounding variables such as cigarette smoking, alcohol and drug abuse. multiple gestation. grand multipara pregnancy, history of IUGR or preterm delivery. fetal abnormality detected at the time of the first scan in the current pregnancy, and maternal vascular disease - were excluded. Confounding variables such as maternal age, maternal weight and gestational age were controlled. Ultrasound imaging was used as a diagnostic tool to establish normal and abnormal fetal growth patterns. A B-mode real time ultrasound unit was used to confirm the gestation age and rule out any obvious fetal abnormalities at 20-24 weeks gestation. Fetal growth scans were done at 28 weeks, 32 weeks and 36 weeks gestation to compare fetal growth patterns in the study and control groups. Fetal biometry used to monitor fetal growth included biparietal diameter (BPD), head circumference (HC), femur length (FL), abdominal circumference (AC) and estimated fetal weight (EFW). Amniotic fluid index (AFI), placental thickness & placental grading were also included. The following variables were analyzed post delivery: • Gestation age at delivery: Normal term delivery is considered to be at 37 - 42 weeks and premature delivery is considered to be less than 37 weeks gestation. The HIV infected and uninfected groups were compared to assess if there \vas a significant difference in the number of preterm deliveries. • Birth weight: The HIV infected and uninfected groups were compared to assess if there was a significant difference in the number of infants with low birth weight. • Perinatal complications: The HIV infected and uninfected groups were compared to assess if there was a significant difference in the number of perinatal complications and to assess if there was an association between the immune status (CD4 T-lymphocyte count) of HIV infected women and perinatal complications. Appropriate ethical principles in medical research were applied. The participant's autonomy, rights and best interests were always considered a priority. Informed consent was obtained from all the participants. Strict confidentiality was adhered to regarding any data collected throughout the study. The Research Ethics Committees at Cape Peninsula University of Technology and University of Cape Town granted ethics approval for the study. Statistical analysis was performed using the statistical package SPSS 12.0.

Maternal diet can have a great impact on the health and development of the fetus. Poor fetal nutrition has been linked to the development of a set of conditions in later life, such as coronary heart disease, type 2 diabetes and hypertension, while restricted growth can result in hypogylcemia, hypocalcemia, hypothermia, polycythemia, hyperbilirubinemia and cerebral palsy. High alcohol consumption during pregnancy can result in Fetal Alcohol Syndrome, a condition that can cause growth retardation, lowered intelligence and craniofacial defects. Current biometric assessment of the fetus involves size-based measures which may not accurately portray the state of fetal development, since they cannot differentiate cases of small-but-healthy or large-but-unhealthy fetuses. This thesis aims to outline a set of more appropriate measures of accurately capturing the state of fetal development. Specifically, soft tissue area and liver volume measurement are examined, followed by facial shape characterisation. A number of tools are presented which aim to allow clinicians to achieve accurate segmentations of these landmark regions. These are modifications on the Live Wire algorithm, an interactive segmentation method in which the user places a number of anchor points and a minimum cost path is calculated between the previous anchor point and the cursor. This focuses on giving the clinician intuitive control over the exact position of the segmented contour. These modifications are FA-S Live Wire, which utilises Feature Asymmetry and a weak shape constraint, ASP Live Wire, which is a 3D expansion of Live Wire, and FA-O Live Wire, which uses Feature Asymmtery and Local Orientation to guide the segmentation process. These have been designed with each of the specific biometric landmarks in mind. Finally, a method of characterising fetal face shape is proposed, using a combination of the segmentation methods described here and a simple shape model with a parameterised b-spline meshing approach to facial surface representation.