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Population-based outcomes of a provincial prenatal screening program : examining impact, uptake, and ethics

Date

2015-04-15

Journal Title

Journal ISSN

Volume Title

Publisher

ORCID

Type

Degree Level

Doctoral

Abstract

The field of prenatal screening and diagnosis has developed rapidly over the past half-century, enabling possibilities for detecting anomalies in reproduction that were never before contemplated. A simple blood sample can aid in the identification of several conditions in the fetus early in the pregnancy. If a fetus is found to be affected by Down syndrome, anencephalus, spina bifida, or Edward's syndrome, a decision must then be made whether to continue or terminate the pregnancy. As prenatal screening becomes increasingly commonplace and part of routine maternal care, researchers are faced with the challenge of understanding its effects at the level of the population and monitoring trends over time. Greater uptake of prenatal screening, when followed by prenatal diagnosis and termination, has important implications for both congenital anomaly surveillance and infant and fetal mortality indicators. Research in Canada suggests that this practice has led to reductions in the congenital-anomaly specific infant mortality rate and increases in the stillbirth rate.(1, 2) The current study is a population-based, epidemiological exploration of demographic predictors of maternal serum screening (MSS) and amniocentesis uptake, with special attention to variations in birth outcomes resulting from different patterns of use. To accomplish our objectives, multiple data sources (vital statistics, hospital and physician services, cytogenetic and MSS laboratory information) were compiled to create a comprehensive maternal-fetal-infant dataset. Data spanned a six-year period (2000-2005) and involved 93,171 pregnancies. A binary logistic regression analysis found that First Nations status, rural-urban health region of residence, maternal age group, and year of test all significantly predicted MSS use. Uptake was lower in women living in a rural health region, First Nations women, and those under 30 years of age. The study dataset identified ninety-four terminations of pregnancy following detection of a fetal anomaly (TOPFA), which led to a lower live birth prevalence of infants with Down syndrome, Trisomy 18, and anencephalus. While a significant increasing trend was observed for the overall infant mortality rate in Saskatchewan between 2001-2005, a clear trend in one direction or the other could not be seen in regards to infant deaths due to congenital anomaly. First Nations status and maternal age were important predictors of both MSS and amniocentesis testing, and appeared to influence the decision to continue or terminate an affected pregnancy. The fact that First Nations women were less likely to screen (9.6% vs. 28.4%) and to have diagnostic follow-up testing (18.5% vs. 33.5%), meant that they were less likely to obtain a prenatal diagnosis when the fetus had a chromosomal anomaly compared to other women (8.3% vs. 27.0%). This resulted in a lower TOPFA rate compare to the rest of the population (0.64 vs. 1.34, per 1,000 pregnancies, respectively) and a smaller difference between the live birth prevalence and incidence of Down syndrome and Trisomy 18 for First Nations women. Women under 30 years of age were much less likely to receive a prenatal diagnosis when a chromosomal anomaly was present (18.4% vs. 31.8%). While risk for a chromosomal anomaly is considerably lower for younger mothers, 53.5% of all pregnancies with chromosomal anomalies and 40.7% of DS pregnancies belonged to this group. Consistent with other studies pregnancy termination rates following a prenatal congenital anomaly diagnosis are high (eg. 74.1% of prenatally diagnosed Down syndrome or Trisomy 18 cases), but these rates may be misleading in that they are based on women who chose to proceed to prenatal diagnosis. The fact that two-thirds (67.3%) of Saskatchewan women who received an increased-risk result declined amniocentesis, helps to put this finding into context. Strong surveillance systems and reasonable access to research datasets will be an on-going challenge for the province of Saskatchewan and should be viewed as a priority. Pregnancies and congenital anomalies are two particularly challenging outcomes to study in the absence of perinatal and congenital anomaly surveillance systems. Still pregnancies that never reach term must be accounted for, in order to describe the true state of maternal-fetal-infant health and to study its determinants. While our study was able to identify some interesting trends and patterns, it is only a snapshot in time. Key to the production of useful surveillance and evaluation is timely information. The current system is not timely, nor is it user-friendly for researchers, health regions or governments. Data compilation for the current study was a gruelling and cumbersome process taking more than five years to complete. A provincial overhaul is warranted in both the mechanism by which researchers access data and in the handling of data. The Better Outcomes Registry & Network (BORN) in Ontario is an innovative perinatal and congenital anomaly surveillance system worthy of modelling.(3) Academic papers in non-ethics' journals typically focus on the technical or programmatic aspects of screening and do not effectively alert the reader to the complex and profound moral dilemmas raised by the practice. A discussion of ethics was felt necessary to ensure a well-rounded portrayal of the issue, putting findings into context and helping to ensure their moral relevance did not remain hidden behind the scientific complexities. Here I lay out the themes of the major arguments in a descriptive manner, recognizing that volumes have been written on the ethics of both screening and abortion. A major ethical tension arising within the context of population based prenatal screening is the tension between community morality and the principle of respect for personal autonomy. Prenatal screening and selective termination have been framed as a purely private or medical matter, thereby deemphasizing the social context in which the practice has materialized and the importance of community values. I consider how a broader sociological perspective, one that takes into account the relevance of community values and limitations of the clinical encounter, could inform key practice and policy issues involving prenatal screening. It is my position that the community's voice must be invited to the conversation and public engagement processes should occur prior to any additional expansion in programming. I end with a look at how the community’s voice might be better heard on key issues, even those issues that at first glance seem to be the problems of individuals. As Rayna Rapp (2000) (4) poignantly observed, women today are 'moral pioneers' not by choice, but by necessity. By elucidating the effects of prenatal screening and the extent of the practice of selective termination in the province, the true occurrence of important categories of congenital anomalies in our province can be observed. Without this knowledge it is very difficult to identify real increases or decreases in fetal and infant mortality over time as the etiologies are complex. Evidence suggests a large and increasing impact of TOPFA on population-based birth and mortality statistics nationally, whereas in Saskatchewan the effect appears to be less pronounced. Appreciation of the intervening effect of new reproductive technologies will be increasingly important to accurate surveillance, research, and evaluation as this field continues to expand.

Description

Keywords

prenatal screening, maternal serum screening, prenatal diagnostic testing, congenital anomaly, termination of pregnancy, perinatal surveillance, infant mortality, fetal mortality, population health indicators, ethics

Citation

Degree

Doctor of Philosophy (Ph.D.)

Department

Community Health and Epidemiology

Program

Community and Population Health Science

Citation

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DOI

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