Obstetrics and Gynaecology - Research Publications

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    State-Wide Utilization and Performance of Traditional and Cell-Free DNA-Based Prenatal Testing Pathways: The Victorian Perinatal Record Linkage (PeRL) Study
    Norton, ME (LIPPINCOTT WILLIAMS & WILKINS, 2021-01)
    (Abstracted from Ultrasound Obstet Gynecol 2020;56:215–224) In recent years, the use of combined first-trimester screening (CFTS) and cell-free DNA (cfDNA) screening has increased. With the rise of CFTS and cfDNA prenatal testing, there has been a dramatic decrease in the number of invasive diagnostic tests performed during pregnancy.
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    Study protocol: childhood outcomes of fetal genomic variants: the PrenatAL Microarray (PALM) cohort study
    Hui, L ; Pynaker, C ; Kennedy, J ; Lewis, S ; Amor, DJ ; Walker, SP ; Halliday, J (BMC, 2021-10-11)
    BACKGROUND: The implementation of genomic testing in pregnancy means that couples have access to more information about their child's genetic make-up before birth than ever before. One of the resulting challenges is the management of genetic variations with unclear clinical significance. This population-based study will help to close this critical knowledge gap through a multidisciplinary cohort study of children with and without genomic copy number variants (CNVs) diagnosed before birth. By comparing children with prenatally-ascertained CNVs to children without a CNV, we aim to (1) examine their developmental, social-emotional and health status; (2) measure the impact of prenatal diagnosis of a CNV on maternal perceptions of child health, behavior and development; and (3) determine the proportion of prenatally-ascertained CNVs of unknown or uncertain significance that are reclassified as benign or pathogenic after 2 or more years. METHODS: This study will establish and follow up a cohort of mother-child pairs who have had a prenatal diagnosis with a chromosomal microarray from 2013-2019 in the Australian state of Victoria. Children aged 12 months to 7 years will be assessed using validated, age-appropriate measures. The primary outcome measures will be the Wechsler Preschool and Primary Scale of Intelligence IV (WPSSI-IV) IQ score (2.5 to 7 year old's), the Ages and Stages Questionnaire (12-30 months old), and the Brief Infant- Toddler Social and Emotional Assessment (BITSEA) score. Clinical assessment by a pediatrician will also be performed. Secondary outcomes will be scores obtained from the: Vineland Adaptive Behavior Scale, Maternal Postnatal Attachment Questionnaire, the Vulnerable Child Scale, Profile of Mood States, Parent Sense of Competence Scale. A descriptive analysis of the reclassification rates of CNVs after ≥2 years will be performed. DISCUSSION: This study protocol describes the first Australian cohort study following children after prenatal diagnostic testing with chromosomal microarray. It will provide long-term outcomes of fetal genomic variants to guide evidence-based pre-and postnatal care. This, in turn, will inform future efforts to mitigate the negative consequences of conveying genomic uncertainty during pregnancy. TRIAL REGISTRATION: ACTRN12620000446965p ; Registered on April 6, 2020.
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    Accelerated fetal growth velocity across the third trimester is associated with increased shoulder dystocia risk among fetuses who are not large-for-gestational-age: A prospective observational cohort study
    MacDonald, TM ; Robinson, AJ ; Hiscock, RJ ; Hui, L ; Dane, KM ; Middleton, AL ; Kennedy, LM ; Tong, S ; Walker, SP ; Fujioka, K (PUBLIC LIBRARY SCIENCE, 2021-10-20)
    OBJECTIVE: To investigate whether fetuses with accelerated third trimester growth velocity are at increased risk of shoulder dystocia, even when they are not large-for-gestational-age (LGA; estimated fetal weight (EFW) >95th centile). METHODS: Fetal growth velocity and birth outcome data were prospectively collected from 347 nulliparous women. Each had blinded ultrasound biometry performed at 28 and 36 weeks' gestation. Change in EFW and abdominal circumference (AC) centiles between 28-36 weeks were calculated, standardised over exactly eight weeks. We examined the odds of shoulder dystocia with increasing EFW and AC growth velocities among women with 36-week EFW ≤95th centile (non-LGA), who went on to have a vaginal birth. We then examined the relative risk (RR) of shoulder dystocia in cases of accelerated EFW and AC growth velocities (>30 centiles gained). Finally, we compared the predictive performances of accelerated fetal growth velocities to 36-week EFW >95th centile for shoulder dystocia among the cohort planned for vaginal birth. RESULTS: Of the 226 participants who had EFW ≤95th centile at 36-week ultrasound and birthed vaginally, six (2.7%) had shoulder dystocia. For each one centile increase in EFW between 28-36 weeks, the odds of shoulder dystocia increased by 8% (odds ratio (OR [95% Confidence Interval (CI)]) = 1.08 [1.04-1.12], p<0.001). For each one centile increase in AC between 28-36 weeks, the odds of shoulder dystocia increased by 9% (OR[95%CI] = 1.09 [1.05-1.12], p<0.001). When compared to the rest of the cohort with normal growth velocity, accelerated EFW and AC velocities were associated with increased relative risks of shoulder dystocia (RR[95%CI] = 7.3 [1.9-20.6], p = 0.03 and 4.8 [1.7-9.4], p = 0.02 respectively). Accelerated EFW or AC velocities predicted shoulder dystocia with higher sensitivity and positive predictive value than 36-week EFW >95th centile. CONCLUSIONS: Accelerated fetal growth velocities between 28-36 weeks' gestation are associated with increased risk of shoulder dystocia, and may predict shoulder dystocia risk better than the commonly used threshold of 36-week EFW >95th centile.
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    Collaborative maternity and newborn dashboard (CoMaND) for the COVID-19 pandemic: a protocol for timely, adaptive monitoring of perinatal outcomes in Melbourne, Australia
    Hui, L ; Marzan, MB ; Potenza, S ; Rolnik, DL ; Said, JM ; Palmer, KR ; Whitehead, CL ; Sheehan, PM ; Ford, J ; Pritchard, N ; Mol, BW ; Walker, SP (BMJ PUBLISHING GROUP, 2021-11)
    BACKGROUND: The COVID-19 pandemic has resulted in a range of unprecedented disruptions to maternity care with documented impacts on perinatal outcomes such as stillbirth and preterm birth. Metropolitan Melbourne has endured one of the longest and most stringent lockdowns in globally. This paper presents the protocol for a multicentre study to monitor perinatal outcomes in Melbourne, Australia, during the COVID-19 pandemic. METHODS: Multicentre observational study analysing monthly deidentified maternal and newborn outcomes from births >20 weeks at all 12 public maternity services in Melbourne. Data will be merged centrally to analyse outcomes and create run charts according to established methods for detecting non-random 'signals' in healthcare. Perinatal outcomes will include weekly rates of total births, stillbirths, preterm births, neonatal intensive care admissions, low Apgar scores and fetal growth restriction. Maternal outcomes will include weekly rates of: induced labour, caesarean section, births before arrival to hospital, postpartum haemorrhage, length of stay, general anaesthesia for caesarean birth, influenza and COVID-19 vaccination status, and gestation at first antenatal visit. A prepandemic median for all outcomes will be calculated for the period of January 2018 to March 2020. A significant shift is defined as ≥6 consecutive weeks, all above or below the prepandemic median. Additional statistical analyses such as regression, time series and survival analyses will be performed for an in-depth examination of maternal and perinatal outcomes of interests. ETHICS AND DISSEMINATION: Ethics approval for the collaborative maternity and newborn dashboard project has been obtained from the Austin Health (HREC/64722/Austin-2020) and Mercy Health (ref. 2020-031). TRIAL REGISTRATION NUMBER: ACTRN12620000878976; Pre-results.
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    Feasibility of using self-reported ethnicity in pregnancy according to the gestation-related optimal weight classification: a cross-sectional study
    Lockie, E ; McCarthy, EA ; Hui, L ; Churilov, L ; Walker, SP (WILEY, 2018-05)
    OBJECTIVE: To evaluate the feasibility of self-reported ethnicity using the gestation-related optimal growth (GROW) classification in a contemporary multicultural antenatal population. DESIGN: Cross-sectional study. SETTING: Tertiary obstetric hospital in Melbourne, Australia. POPULATION: Pregnant women attending the antenatal clinic. METHODS: We surveyed pregnant women during April-June 2016 regarding their understanding of the term 'ethnicity', and how they would classify the ethnicity of themselves, their partner, and family members according to the Australian GROW classification. RESULTS: Two hundred and thirty-five women completed the survey. When describing 'ethnicity', most women (103, 44%) chose multiple descriptors, most frequently country of birth (54%) and region of ancestry (47%). Interpretation of 'ethnicity' varied significantly between ethnic groups: those choosing 'country of birth' were more likely to identify as Indian (odds ratio, OR 3.5, P = 0.03), whereas those choosing 'physical appearance' were more likely to identify as Chinese (OR 3.0, P = 0.047). Thirty participants (13%) were unable to describe their ethnicity from the available GROW options. Sixty-one (26%) respondents' ethnicity was inconsistent with that of their parents' heritage. A further 35% had a partner of different ethnicity. The agreement between country of birth and self-reported ethnicity was only fair (kappa 0.73, 95% confidence interval, 95% CI 0.64-0.82). CONCLUSION: This study confirms the complexity of defining ethnicity in contemporary multicultural settings. Self-reported ethnicity is often inaccurate, concepts of ethnicity vary by ethnic group, and country of birth is a poor descriptive surrogate. Adjustment for maternal ethnicity should be undertaken with caution in the customised assessment of fetal growth. TWEETABLE ABSTRACT: Is self-reported maternal ethnicity reliable? We think not.
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    Declining invasive prenatal diagnostic procedures: A comparison of tertiary hospital and national data from 2012 to 2015
    Johnson, K ; Kelley, J ; Saxton, V ; Walker, SP ; Hui, L (WILEY, 2017-04)
    BACKGROUND: In recent years, the superior accuracy of maternal plasma cell-free DNA-based prenatal screening has resulted in >50% national decline in amniocenteses and chorionic villus sampling (CVS), creating new implications for specialist training. OBJECTIVE: To compare the annual figures on amniocenteses and CVS in a tertiary hospital with national population-based trends between 2012 and 2015. METHODS: Retrospective study examining the amniocentesis and CVS procedures performed in a tertiary hospital between 2012 and 2015. Numbers of procedures, indications for testing, type of test and diagnostic results were analysed. Trends in the annual numbers of procedures were compared to national population-based data from Medicare Benefits Schedule database. RESULTS: The annual numbers of diagnostic procedures in our tertiary centre fell from 267 to 215 over the study period, representing a 19.5% decline. This was significantly smaller than the corresponding national decline of 53.7% for the same period (P < 0.0001). In 2015, ultrasound abnormality (including nuchal translucency ≥ 3.5 mm) surpassed high-risk screening results as the most common indication for invasive testing. Thirty percent of procedures performed for an ultrasound abnormality occurred prior to 18 weeks gestation. CONCLUSION: Our tertiary centre experienced a relatively smaller decline in prenatal diagnostic procedures compared with national figures, largely due to an increase in testing for ultrasound abnormalities. Our results demonstrate the increasing contribution of first trimester ultrasound in the detection of fetal abnormalities in the cell-free DNA era and the continued viability of specialist training in invasive procedures.
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    Fetal fraction and noninvasive prenatal testing: What clinicians need to know
    Hui, L ; Bianchi, DW (WILEY, 2020-01)
    The fetal fraction (FF) is a function of both biological factors and bioinformatics algorithms used to interpret DNA sequencing results. It is an essential quality control component of noninvasive prenatal testing (NIPT) results. Clinicians need to understand the biological influences on FF to be able to provide optimal post-test counseling and clinical management. There are many different technologies available for the measurement of FF. Clinicians do not need to know the details behind the bioinformatics algorithms of FF measurements, but they do need to appreciate the significant variations between the different sequencing technologies used by different laboratories. There is no universal FF threshold that is applicable across all platforms and there have not been any differences demonstrated in NIPT performance by sequencing platform or method of FF calculation. Importantly, while FF should be routinely measured, there is not yet a consensus as to whether it should be routinely reported to the clinician. The clinician should know what to expect from a standard test report and whether reasons for failed NIPT results are revealed. Emerging solutions to the challenges of samples with low FF should reduce rates of failed NIPT in the future. In the meantime, having a "plan B" prepared for those patients for whom NIPT is unsuccessful is essential in today's clinical practice.
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    Association between timing of diagnosis of trisomy 21, 18, and 13 and maternal socio-economic status in Victoria, Australia: A population-based cohort study from 2015 to 2016
    Kluckow, E ; Halliday, J ; Poulton, A ; Lindquist, A ; Hutchinson, B ; Bethune, M ; Bonacquisto, L ; Da Silva Costa, F ; Gugasyan, L ; Harraway, J ; Howden, A ; Kulkarni, A ; Martin, N ; McCoy, R ; Menezes, M ; Nisbet, D ; Palma-Dias, R ; Pertile, MD ; Poulakis, Z ; Hui, L (WILEY, 2019-12)
    OBJECTIVES: To explore the association between timing of diagnosis of common autosomal trisomies, maternal age, and socio-economic status (SES). DESIGN: Retrospective study of cytogenetic diagnoses of trisomy 21 (T21), trisomy 18 (T18), and trisomy 13 (T13) in Victoria, Australia, in 2015 to 2016, stratified by timing (prenatal less than 17 weeks gestation, prenatal including or greater than or 17 weeks gestation, and postnatal before 12 months of age), maternal age, and SES region. Utilisation of prenatal testing following a live-born T21 infant was ascertained via record linkage. RESULTS: Among 160 230 total births were 571 diagnoses of T21 and 246 of T18/T13. The overall and live birth prevalences of T21 were 3.56 and 0.47 per 1000 births, respectively. Compared with women from disadvantaged SES regions, women from high SES regions were more likely to have a prenatal diagnosis of a trisomy before 17 weeks than after (P < .01) and less likely to have a live-born T21 infant than a prenatal diagnosis (P < .01). There was a significant trend to higher live birth rates of T21 with lower SES (P = .004). The majority (68.5%) of women who gave birth to a live infant with T21 did not utilise prenatal testing. CONCLUSION: There is a significant relationship between lower SES, later prenatal diagnosis of trisomy, and higher live birth rate of T21 in Victoria.