An update on current prenatal testing options: first trimester and noninvasive prenatal testing

Clinical Applications of Fetal Cell-Free DNA: State of the Science

Advances in technology have correlated with expanding prenatal genetic testing options for pregnant people. Leading medical organizations recommend cell-free DNA as the most sensitive screening test for trisomies 13, 18, and 21, as well as for fetal sex chromosome aneuploidies. The commercially available testing options go beyond these recommended tests, and prenatal care professionals should be familiar with the tests that their patients may choose despite being beyond the scope of current medical recommendations. This article explains updates in cell-free DNA technology and clinical considerations for prenatal care professionals, recognizing that this is a rapidly changing field of science and health care.

[Effect of high-fat diet and exercise on asprosin and CTRP6 expression in subcutaneous and retroperitoneal adipose tissues in rats during mid-gestation]

OBJECTIVE

To study the effects of high-fat (HF) diet and exercise on the expressions of asprosin and CTRP6 in adipose tissues in different regions of rats during mid-gestation.

METHODS

Pregnant SD rats were fed on a standard chow diet or a high-fat (60% fat content) diet for 14 days starting on gestation day (GD) 1. Starting from GD3, the rats fed either on normal or high-fat diet in the exercise groups (CH-RW and HF-RW groups) were allowed access to the running wheels for voluntary running, and those in sedentary groups (CH-SD and HF-SD groups) remained sedentary. At the end of the 14 days, adipose tissues were sampled from different regions of the rats for detecting the mRNA and protein expressions of asprosin and CTRP6 using RT-qPCR and Western blotting.

RESULTS

The mRNA expression of asprosin in retroperitoneal adipose tissues was significantly higher in HF-RW group than in the other 3 groups (P < 0.0001). Asprosin mRNA expression in subcutaneous adipose tissues was significantly higher in HF-SD group than in CH-SD group (P=0.0234) and comparable between HF-RW and CH-SD groups (P=0.0494). CTRP6 mRNA expression in retroperitoneal adipose tissues was also significantly higher in HF-RW group than in the other groups (P < 0.0001), and CTRP6 protein expression was signficiantly higher in HF-RW group than in CH-RW and HF-SD groups (P < 0.05). In subcutaneous adipose tissues, CTRP6 mRNA expression was significantly higher in CH-RW group than in HF-SD and HF-RW groups (P < 0.05). The protein expression level of CTRP6 in subcutaneous adipose tissues showed a significant negative correlation with blood glucose (r=-0.6038, P=0.0172), while its expression in retroperitoneal adipose tissues was positively correlated with blood glucose (r=0.5305, P= 0.0285); the mRNA expression levels of asprosin and CTRP6 were significantly lower in subcutaneous than in retroperitoneal adipose tissues (P < 0.0001).

CONCLUSIONS

High-fat diet and exercise during mid-gedtation can affect the expression levels of asprosin and CTRP6 in adipose tissues of rats in a site-specific manner.

Evolution of Down Syndrome Prenatal Screening Clinical Practices in Québec

OBJECTIVE

Prenatal screening for Down syndrome (DS) has evolved greatly over the last decades with the improvement of first- and second-trimester serum screening and the introduction of cell-free fetal DNA. This study aimed to estimate the impact of such changes on practices.

METHODS

This retrospective cohort study included fetuses and newborns diagnosed with DS between 2005-2007 and 2015-2017 in the single obstetrical care centre in Québec City. Data were collected on the prenatal screening method, diagnosis, and delivery. The median was compared between the study periods.

RESULTS

Complete clinical data were available for only 78 (66%) of 119 cases of DS. Significant changes were observed in screening methods, including an increase in the use of first-trimester serum, ultrasound, and cell-free fetal DNA. No significant changes were noted in terms of gestational age at diagnosis (median [interquartile range; IQR]: 17.0 [16.0-20.9] weeks in 2005-2007 vs. 17.9 [16.3-22.5] weeks in 2015-2017; P = 0.49) and delivery or termination of pregnancy (median 20.9 [IQR 18.0-23.3] weeks in 2005-2007 vs. 21.3 [18.4-23.4] weeks in 2015-2017; P = 0.46). The methods of diagnosis did not change significantly over the decade, with amniocentesis used 85% and 79% of the time, respectively (P = 0.19).

CONCLUSION

The increased use of first-trimester screening and cell-free fetal DNA tests was not associated with earlier diagnosis of DS or earlier delivery or termination of pregnancy. The use of chorionic villus sampling should be encouraged for DS diagnosis when indicated because it could reduce the gestational age at diagnosis and termination if requested.

Informed Decision Making Regarding Prenatal Aneuploidy Screening

OBJECTIVE

To explore informed decision making for prenatal aneuploidy screening (PAS) by investigating the relationships among women's understanding of PAS, their health literacy, and their satisfaction with their decisions regarding PAS.

DESIGN

A descriptive, cross-sectional, correlational study.

SETTING

Southeastern United States.

PARTICIPANTS

Ninety-five adult women who were at least 18 weeks pregnant; most were White non-Hispanic (n = 75, 78.9%) and college educated (n = 56, 59.0%).

METHODS

Potential participants were invited to complete an online survey that was distributed via e-mail to recipients of an electronic pregnancy and parenting newsletter. The survey included questions about women's understanding of PAS, their health literacy, and their satisfaction with their decisions regarding PAS based on three validated instruments. I used descriptive statistics, bivariate correlational analysis, and multiple linear regression to analyze the data.

RESULTS

Higher level of education (β =.225, p = .038) and higher scores from the Health Literacy Questionnaire's scale Ability to Actively Engage With Health Care Providers (β =.317, p = .004) were significantly associated with increased understanding of PAS. Higher scores on two scales from the Health Literacy Questionnaire, Feeling Understood andSupportedby Health Care Providers (β =.329 , p = .004) and Ability to Find Good Health Information (β = .402, p = .013), were significantly associated with greater satisfaction with decisions regarding prenatal aneuploidy screening. Forty-two percent (n = 40) of participants did not report satisfaction with PAS.

CONCLUSION

A woman's health literacy and her ability to actively engage with health care providers are critical for informed decision making about PAS. Findings highlight the need for woman-centered strategies to promote open and intentional communication about PAS.

Certified Nurse-Midwives' Experiences With Provision of Prenatal Genetic Screening: A Case for Interprofessional Collaboration

Prenatal genetic screening (GS) for the most common autosomal aneuploidies encompasses maternal serum screening (MSS) and noninvasive prenatal testing (NIPT, or cell-free fetal DNA testing). In the United States, most maternity care is provided by obstetrician-gynecologists; however, women are increasingly utilizing the services of certified nurse-midwives (CNMs). Currently, limited research exists on midwives' experiences with providing prenatal GS. Therefore, the purpose of this study was to explore CNMs' experiences in providing prenatal GS. A semistructured guide focused on MSS and NIPT was used to interview a convenience sample of 13 CNMs. Results were coded and analyzed using grounded theory to elicit overarching themes. Results were organized into 6 themes describing CNMs' prenatal GS provision: (1) clinical protocols; (2) patient education; (3) patient-CNM shared decision-making process; (4) testing initiation; (5) results delivery; and (6) follow-up coordination. Key influences on midwives' perspectives on offering prenatal GS included a noninterventionist approach to pregnancy and past experiences with false-positive MSS results. Participants had an understanding of prenatal GS that was appropriate to midwifery scope of practice. Results indicate that NIPT utilization is compatible with the midwifery philosophy of noninterventionism, although midwives had limited experiences with NIPT to date.

“Love Is a Choice”: Couple Responses to Continuing Pregnancy With a Lethal Fetal Diagnosis

While it is known that couples experience pregnancy differently from one another, the circumstance of continuing pregnancy after learning of a lethal fetal diagnosis has received little attention. This longitudinal, naturalistic study of 16 mothers and 14 spouses/partners aimed to describe pregnant couples’ responses and relationships in continued pregnancy with lethal fetal diagnosis and to examine similarities and differences within those couple responses. Individual and joint interviews with parents were conducted across pregnancy, birth, and death of the baby. Within and across couple analysis was performed. Three categories emerged (Pregnant vs. Not Pregnant; Individual Responses to Adversity; Strength of the Couple Relationship) with 12 themes. Findings indicate that individual responses to these stressful pregnancies were inherent in who was physically pregnant, choosing whether to love and embrace the unborn baby, personal characteristics, and the strength of the couple relationship. Care providers should assess couple dynamics. Couples with committed relationships, shared decision-making, and mutual support fared the best in the aftermath of their baby’s death.

Isolated intracardiac echogenic focus on routine ultrasound: implications for practice

Ultrasound is widely used as a screening tool for fetal anomalies. An intracardiac echogenic focus (ICEF) is associated with fetal aneuploidy, particularly trisomy 21, when found with other minor abnormalities known as soft markers. However, when found in isolation, intracardiac echogenic foci are morphologic variations with little or no pathologic significance for the fetus. Ambiguity about the significance of ICEF and other soft markers and the lack of preparation prior to ultrasound can result in unnecessary worry for women and their partners. A variety of tools exist that providers can use to help pregnant women and their partners make informed decisions about ultrasound and fetal screening.

Noninvasive prenatal testing in routine clinical practice for a high-risk population: Experience from a center

This study aimed to summarize the effects of noninvasive prenatal testing (NIPT) on aneuploidy among high-risk participants in Tangshan Maternal and Children Health Hospital.NIPT or invasive prenatal diagnosis was recommended to patients with a high risk of fetal aneuploidy from February 2013 to February 2014. Patients who exhibited eligibility and applied for NIPT from January 2012 to January 2013 were included in a comparison group. The rates of patients who underwent invasive testing, declined to undergo further testing, and manifested trisomies 21, 18, and 13 were compared between two groups. Follow-up data were obtained from the participants who underwent NIPT from 2013 to 2014.A total of 7223 patients (3018 and 4205 individuals before and after NIPT) were eligible for analysis. After NIPT was introduced in 2013 to 2014, 727 patients (17.3%) underwent invasive testing, 2828 preferred NIPT (67.3%), and 650 declined to undergo further testing (15.5%). A total of 34 cases of trisomies 21, 18, and 13 (0.8%) were found. In 2012 to 2013, 565 patients (18.7%) underwent invasive testing and 2453 declined to undergo further testing (81.3%). A total of 7 cases of trisomies 21, 18, and 13 were documented (0.2%). Of these cases, 24 were found from NIPT and 10 cases were found from invasive testing. The number of participants who declined to undergo further testing significantly decreased after NIPT was introduced (81.3% vs. 15.5%, P < 0.001). The sensitivity and specificity of NIPT for trisomies 21, 18, and 13 were 100% and 99.9%, respectively. The detection rates of NIPT for trisomies 21, 18, and 13 also significantly increased (0.2% vs. 0.8%, P < 0.001). By contrast, the overall rates of invasive testing remained unchanged (18.7% vs. 17.3%, P = 0.12). The positive predictive values of NIPT for trisomies 21, 18, and 13 were 100%, 83.3%, and 50.0%, respectively. The false positive rates of NIPT were 0% and 0.04%.With NIPT implementation in clinical practice, the rate of declining a follow-up test among high-risk women was decreased and the detection rate of prenatal chromosomal aneuploidy for trisomies 21, 18, and 13 was increased without requiring numerous invasive procedures.

Public Perceptions of Recessive Carrier Testing in the Preconception and Prenatal Periods

OBJECTIVE

To explore public perceptions of preconception and prenatal recessive carrier testing.

DESIGN

Qualitative, descriptive.

SETTING

Chat rooms located in four websites targeted to those who are pregnant or planning a pregnancy.

PARTICIPANTS

Anonymous comments (N = 1925) in online chat rooms.

METHODS

The Centers for Disease Control and Prevention's (CDC) Analytic validity, Clinical validity, Clinical utility, Ethical, legal, social implications Model Process (ACCE) for evaluating a genetic test guided this deductive-inductive content analysis.

RESULTS

Participant perceptions of the clinical utility of recessive carrier screening with universal carrier panels are multidimensional. Data analysis revealed four a priori deductive themes present in the data. Secondary inductive analysis produced 20 themes, which exceeded the scope of the CDC's ACCE Model Process for assessing the clinical utility of a genetic test.

CONCLUSION

Participant perceptions of carrier testing are important to consider in the clinical utility of carrier testing. Participant perceptions of clinical utility vary from those of the CDC's ACCE Model Process and should be considered in evaluation of the clinical utility of recessive carrier testing in the preconception and prenatal populations.