Expanded carrier screening for autosomal-recessive conditions effectively identifies more carrier couples than traditional guideline-based carrier screening. However, clinically available expanded carrier screening panels include numerous conditions, some of which have questionable clinical utility as a result of very low carrier frequency, low or unknown testing sensitivity, and mild or incompletely penetrant phenotypes. Using the 2013 American College of Medical Genetics and Genomics Position Statement on Prenatal and Preconception Expanded Carrier Screening and the 2017 American College of Obstetricians and Gynecologists' Committee Opinion on Carrier Screening in the Age of Genomic Medicine as guidance, we propose specific criteria for the development of expanded carrier screening panels that will maximize clinical utility and minimize patient stress, unnecessary cost of follow-up testing, and clinician time spent facilitating and performing follow-up counseling and testing. We identified 96 conditions that meet our proposed criteria, far more than current guidelines recommend. On the other hand, a considerable percentage (73%) of conditions on current expanded carrier screen panels does not meet our proposed criteria. The purpose of this commentary is to acknowledge the benefits of expanded panels, but to also recognize that in their current state, we are putting patients at risk for undue stress and spending excessive time and money on follow-up testing for remarkably rare or mild conditions and conditions with low screening performance. We encourage laboratories and clinicians to work together to create the most clinically useful screening panels for patients desiring reproductive risk information.

We have previously demonstrated inverse associations between maternal 25(OH)‐vitamin D status and perinatal DNA methylation at the retinoid‐X‐receptor‐alpha (RXRA) locus and between RXRA methylation and offspring bone mass. In this study, we used an existing randomized trial to test the hypothesis that maternal gestational vitamin D supplementation would lead to reduced perinatal RXRA locus DNA methylation. The Maternal Vitamin D Osteoporosis Study (MAVIDOS) was a multicenter, double‐blind, randomized, placebo‐controlled trial of 1000 IU/day cholecalciferol or matched placebo from 14 weeks’ gestation until delivery. Umbilical cord (fetal) tissue was collected at birth and frozen at −80°C ( n = 453). Pyrosequencing was used to undertake DNA methylation analysis at 10 CpG sites within the RXRA locus (identified previously). T tests were used to assess differences between treatment groups in methylation at the three most representative CpG sites. Overall, methylation levels were significantly lower in the umbilical cord from offspring of cholecalciferol‐supplemented mothers, reaching statistical significance at four CpG sites, represented by CpG5: mean difference in % methylation between the supplemented and placebo groups was −1.98% (95% CI, −3.65 to −0.32, p = 0.02). ENCODE (Encyclopedia of DNA Elements) evidence supports the functionality of this locus with strong DNase hypersensitivity and enhancer chromatin within biologically relevant cell types including osteoblasts. Enrichment of the enhancer‐related H3K4me1 histone mark is also seen in this region, as are binding sites for a range of transcription factors with roles in cell proliferation, response to stress, and growth factors. Our findings are consistent with previous observational results and provide new evidence that maternal gestational supplementation with cholecalciferol leads to altered perinatal epigenetic marking, informing mechanistic understanding of early life mechanisms related to maternal vitamin D status, epigenetic marks, and bone development. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

A majority of counselors neither felt properly equipped nor comfortable counseling patients with prenatal cfDNA results suggestive of maternal neoplasm. This study demonstrates a need for collaboration amongst clinicians, researchers, and laboratories to publish data regarding NIPT results indicative of maternal neoplasm, and for the creation of management guidelines. © 2016 John Wiley & Sons, Ltd.

Objective This study was aimed to systematically review the use of filtering facepiece respirators, such asN95 masks, during pregnancy. Study Design A comprehensive search for primary literature using Medline, Embase, Scopus, Web of Science, and ClinicalTrials.gov was conducted from inception until April 2020 to find articles reporting outcomes of pregnant women using filtering facepiece respirator (FFR). Studies were selected if they included the use of FFR in pregnant women and reported an outcome of interest including physiologic changes (heart rate, respiratory rate, pulse oximetry, and fetal heart rate tracing) or subjective measures (thermal or exertional discomfort or fit). The Newcastle-Ottawa Quality Assessment scale was used to assess the risk of bias. The main outcome was to describe the physiologic changes in pregnant women compared with nonpregnant women. Due to the small number of studies and heterogeneity of reported outcomes a meta-analysis was not conducted. Results of the studies were synthesized into a summary of evidence table. Results We identified four studies, three cohort studies and one crossover study, comprising 42 women using FFR during pregnancy. Risk of bias was judged to be low. Studies were consistent in showing no significant increase in maternal heart rate, respiratory rate, oxygen saturation, and fetal heart rate between pregnant and nonpregnant women using N95 FFRs for short durations. Repeat fit testing was not supported for women gaining the recommended amount of weight during pregnancy. No evidence was found to reach conclusions about prolonged N95 FFR use in pregnancy. Conclusion Limited duration N95 FFR use during pregnancy is unlikely to impart risk to the pregnant women or her fetus. Key Points

Pregnant patients should be offered the option of prenatal genetic screening and diagnostic testing. The type of screening and testing offered to a patient may depend on various factors including but not limited to age, family history, fetal findings, exposures, and patient preferences. Prenatal screening is available for a variety of genetic conditions including aneuploidy, congenital abnormalities, and carrier status. Diagnostic testing options include karyotype, prenatal microarray, as well as next‐generation sequencing. The various options differ in methodology, accuracy, timing and indication for testing, and information they provide. Given that the technologies related to prenatal testing are rapidly evolving and improving, the array of available screening and testing modalities are increasing. This article reviews the current offerings in prenatal screening and diagnosis.