Disclaimer: This practice resource is designed primarily as an educational resource for medical geneticists and other clinicians to help them provide quality medical services. Adherence to this practice resource is completely voluntary and does not necessarily assure a successful medical outcome. This practice resource should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the clinician should apply his or her own professional judgment to the specific clinical circumstances presented by the individual patient or specimen. Clinicians are encouraged to document the reasons for the use of a particular procedure or test, whether or not it is in conformance with this practice resource. Clinicians also are advised to take notice of the date this practice resource was adopted, and to consider other medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures.Carrier screening began 50 years ago with screening for conditions that have a high prevalence in defined racial/ethnic groups (e.g., Tay-Sachs disease in the Ashkenazi Jewish population; sickle cell disease in Black individuals). Cystic fibrosis was the first medical condition for which panethnic screening was recommended, followed by spinal muscular atrophy. Next-generation sequencing allows low cost and high throughput identification of sequence variants across many genes simultaneously. Since the phrase "expanded carrier screening" is nonspecific, there is a need to define carrier screening processes in a way that will allow equitable opportunity for patients to learn their reproductive risks using next-generation sequencing technology. An improved understanding of this risk allows patients to make informed reproductive decisions. Reproductive decision making is the established metric for clinical utility of population-based carrier screening. Furthermore, standardization of the screening approach will facilitate testing consistency. This practice resource reviews the current status of carrier screening, provides answers to some of the emerging questions, and recommends a consistent and equitable approach for offering carrier screening to all individuals during pregnancy or preconception.

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Expanded carrier screening (ECS) is a relatively new carrier screening option that assesses many conditions simultaneously, as opposed to traditional ethnicity-based carrier screening for a limited number of conditions. This study aimed to explore pregnant women's perspectives on ECS, including reasons for electing or declining and anxiety associated with this decision-making. A total of 80 pregnant women were surveyed from Northwestern Medicine's Clinical Genetics Division after presenting for aneuploidy screening. Of the 80 participants, 40 elected and 40 declined ECS. Trends regarding reasons for electing or declining ECS include ethnicity, desire for genetic risk information, lack of family history, perceived likelihood of being a carrier, and perceived impact on reproductive decisions. Individuals who declined ECS seemed to prefer ethnicity-based carrier screening and believed that ECS would increase their anxiety, whereas individuals who elected ECS seemed to prefer more screening and tended to believe that ECS would reduce their anxiety. These findings provide insight on decision-making with regard to ECS and can help guide interactions that genetic counselors and other healthcare providers have with patients, including assisting patients in the decision-making process.

This retrospective study compared the prenatal ultrasound (US) diagnosis with autopsy findings in 61 intact fetuses following induced abortion and 36 fragmented fetuses from dilatation and evacuation (D&E). In intact fetuses, complete agreement between US diagnosis and autopsy findings was achieved in 65.6% of cases in the central nervous system (CNS) and 47.5% in other somatic organ systems (SOS). There were major differences between US and autopsy findings involving the CNS in 6.5% of cases and SOS in 27.9%. Correlation was better for evaluation of renal anomalies (complete agreement in 63.6% of 11 suspected cases, 2 false-positive and no false-negative cases) than congenital heart disease (complete agreement in 27.3% of 11 suspected cases, 5 false-positive and 3 false-negative cases). In D&E specimens, a prenatal diagnosis of neural tube defect (NTD) was confirmed in 90% of cases. However, due to fragmentation of fetal parts, the US diagnosis in the CNS could not be confirmed totally (69.4%) or partially (2.8%) in fetuses with chromosomal abnormalities (ChA) or multiple congenital anomalies (MCA). Nonetheless, the US diagnosis of SOS was confirmed in six cases on D&E, including Meckel-Gruber syndrome, cystic hygroma, renal agenesis with contralateral renal dysplasia, cardiac defect, fetal hydrops, and tracheal atresia. Our results show that a thorough autopsy of an intact fetus after abortion is necessary to confirm prenatal diagnosis and allow proper management and counseling. The pathologic examination of D&E specimens can reliably confirm the US diagnosis of NTD, but it is very limited in identifying other fetal anomalies.