Antenatal care implications of population‐based trends in Down syndrome birth rates by rurality and antenatal care provider, Queensland, 1990–2004

The 'Institutional Lottery': Institutional variation in the processes involved in accessing late abortion in Victoria, Australia

Despite abortion being decriminalised in Victoria, Australia, access remains difficult, especially at later gestations. Institutions (i.e. health services) place restrictions on the availability of late abortions and/or require additional requirements to be satisfied (e.g. Hospital Termination Review Committee approval), as a consequence of local regulation (i.e. policies and processes determined at the institutional level). This paper reports on the results of 27 interviews with Victorian health professionals about late abortion processes and the operation of Termination Review Committees in Victorian health services, which were analysed thematically. The results reveal the operation of an 'institutional lottery' whereby patients' experiences in seeking late abortion services were variable and largely shaped by the institution(s) they found themselves in.

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

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.

A clinical audit of combined first trimester screening and non-invasive prenatal testing offered to pregnant women in a regional Australian hospital

The records of women attending a large Australian regional hospital for antenatal care were retrospectively analysed to determine what proportion had undergone or been offered first trimester screening for fetal abnormalities; only 609 (54%) of 1114 women had undergone or been offered screening. Younger women, multiparous women and women living in rural Australia were less likely to be offered screening. Barriers to screening and solutions for overcoming these need to be identified to improve access and equality in antenatal screening for all women.

What are the costs associated with child and maternal healthcare within Australia? A study protocol for the use of data linkage to identify health service use, and health system and patient costs

INTRODUCTION

The current literature in Australia demonstrates that there are variations in access and outcomes in perinatal care based on socioeconomic factors. However, little has been done looking at the level of out-of-pocket healthcare costs associated with perinatal care. The primary aim of this project will be to quantify health service use and out-of-pocket healthcare expenditure associated with childbearing and early childhood in Queensland, Australia.

METHODS AND ANALYSIS

This project will build Australia's first model (called Maternal & Child Cost MOD) of out-of-pocket healthcare expenditure by using administrative data from the Queensland Perinatal Data Collection, of all childbearing women and their resultant children, who gave birth in Queensland between 1 July 2012 and 30 June 2016.The current costs to the health system and out-of-pocket health care expenditure of patients associated with maternity and early childhood health care will be identified. The differences in costs based on indigenous identification, socioeconomic status and geographic location will be assessed using linear regression modelling and counterfactual modelling techniques.

ETHICS AND DISSEMINATION

Human Research Ethics approval has been obtained from Townsville Hospital and Health Service Human Research Ethics Committee (HREC) (HREC Reference number: HREC/16/QTHS/223). Consent will not be sought from participants whose de-identified data will be used in this study. Permission to waive consent has been gained from Queensland Health under the Public Health Act 2005.The results of this study will be disseminated through publications in peer-reviewed journals and through presentations at conferences, regionally and nationally. Our target audience is clinicians, health professionals and health policy-makers.

Trends and characteristics of fetal and neonatal mortality due to congenital anomalies, Colombia 1999-2008

OBJECTIVE

To describe fetal and neonatal mortality due to congenital anomalies in Colombia.

METHODS

We analyzed all fetal and neonatal deaths due to a congenital anomaly registered with the Colombian vital statistics system during 1999-2008.

RESULTS

The registry included 213,293 fetal deaths and 7,216,727 live births. Of the live births, 77,738 (1.08%) resulted in neonatal deaths. Congenital anomalies were responsible for 7321 fetal deaths (3.4% of all fetal deaths) and 15,040 neonatal deaths (19.3% of all neonatal deaths). The fetal mortality rate due to congenital anomalies was 9.9 per 10,000 live births and fetal deaths; the neonatal mortality rate due to congenital anomalies was 20.8 per 10,000 live births. Mortality rates due to congenital anomalies remained relatively stable during the study period. The most frequent fatal congenital anomalies were congenital heart defects (32.0%), central nervous system anomalies (15.8%), and chromosomal anomalies (8.0%). Risk factors for fetal and neonatal death included: male or undetermined sex, living in villages or rural areas, mother's age >35 years, low and very low birthweight, and <28 weeks gestation at birth.

CONCLUSIONS

Congenital anomalies are an important cause of fetal and neonatal deaths in Colombia, but many of the anomalies may be preventable or treatable.

Normal ranges for fetal nasal bone length determined by ultrasound at 18-20 weeks of gestation in a multiethnic Australian population

OBJECTIVE

Absence or hypoplasia of the nasal bone is commonly reported in Down syndrome fetuses. We define normal ranges and the 2.5th centile for fetal nasal bone length (NBL) in a multiethnic Australian population at 18-20 weeks of gestation.

METHODS

A prospective cohort study of women attending for a routine anomaly scan. Ethnicity of the patient and their partner was recorded, and the nasal bone was measured three times. Two methods of nasal bone assessment were used to define normal ranges: a single (first) measurement and the mean value of three measurements. Mixed-effects regression models were employed to account for interoperator differences treating sonographers as random effects. Nonparametric methods were used to define the 2.5th centile for gestational age.

RESULTS

A total of 1199 women were included with a mean gestational age 19.1 (SD 0.4; range 18-20) weeks. There is significant linear relationship between NBL and gestational age (P<0.001). The mean of three nasal bone measurements had a smaller standard deviation than single nasal bone measurements. Nonparametric assessment was used to define the 2.5th centile, which is 4.4 mm at 18 weeks and 5.0 mm at 20 weeks of gestation.

CONCLUSIONS

This study provides a reference range for fetal NBL at 18-20 weeks of gestation in an unselected multiethnic Australian population. Whilst NBL increases linearly from 18 to 20 weeks, the data are not normally distributed and nonparametric techniques are required to define the 2.5th centile. The mixed-effects model also accounts for variation in sonographer measurements.

Is Down syndrome a disappearing birth defect?

OBJECTIVE

To assess trends in the prevalence of Down syndrome (DS) from 1986 to 2004 in Victoria, Australia (population approximately 5 million).

STUDY DESIGN

The Victorian Birth Defects Register and the Prenatal Diagnosis Database were linked to ascertain all cases of DS. Total and birth prevalence estimates were calculated per year and presented as 3-year moving averages.

RESULTS

The total number of cases of DS increased from 113 in 1986 to 188 in 2004. The number of births declined over the first decade of the study, particularly in younger women, but total numbers have fluctuated between 45 and 60 births since 1996. In women under age 35 years, total prevalence was 10/10,000 until 1997 and then increased to 12.5/10,000. In older women, total prevalence increased from 70/10,000 to 90/10,000 in this time frame. Birth prevalence declined at first but remained relatively stable in the later years of the study. The proportion of cases diagnosed prenatally increased from 3% to 60% in younger women.

CONCLUSIONS

Our findings demonstrate the continuing need to devote resources to support individuals with DS and their families.

Meiosis in oocytes: predisposition to aneuploidy and its increased incidence with age

Mammalian oocytes begin meiosis in the fetal ovary, but only complete it when fertilized in the adult reproductive tract. This review examines the cell biology of this protracted process: from entry of primordial germ cells into meiosis to conception. The defining feature of meiosis is two consecutive cell divisions (meiosis I and II) and two cell cycle arrests: at the germinal vesicle (GV), dictyate stage of prophase I and at metaphase II. These arrests are spanned by three key events, the focus of this review: (i) passage from mitosis to GV arrest during fetal life, regulated by retinoic acid; (ii) passage through meiosis I and (iii) completion of meiosis II following fertilization, both meiotic divisions being regulated by cyclin-dependent kinase (CDK1) activity. Meiosis I in human oocytes is associated with an age-related high rate of chromosomal mis-segregation, such as trisomy 21 (Down's syndrome), resulting in aneuploid conceptuses. Although aneuploidy is likely to be multifactorial, oocytes from older women may be predisposed to be becoming aneuploid as a consequence of an age-long decline in the cohesive ties holding chromosomes together. Such loss goes undetected by the oocyte during meiosis I either because its ability to respond and block division also deteriorates with age, or as a consequence of being inherently unable to respond to the types of segregation defects induced by cohesion loss.

Epidemiology of Down syndrome

Down syndrome (DS) is the most commonly identified genetic form of mental retardation and the leading cause of specific birth defects and medical conditions. Traditional epidemiological studies to determine the prevalence, cause, and clinical significance of the syndrome have been conducted over the last 100 years. DS has been estimated to occur in approximately 1 in 732 infants in the United States, although there is some evidence that variability in prevalence of estimates exist among racial/ethnic groups. Progress has been made in characterizing the specific types of chromosome errors that lead to DS and in identifying associated factors that increase the risk of chromosome 21 malsegregation, i.e., advanced maternal age and recombination. Studies to examine the variability of the presence of specific DS-associated birth defects and medical conditions provide evidence for genetic and environmental modifiers. Here, we provide a brief survey of studies that address the current state of the field and suggest gaps in research that can soon be filled with new multidisciplinary approaches and technological advances.