Faculty Bibliography

OBJECTIVE:This study aimed to estimate the perinatal mortality associated with prenatally diagnosed vasa previa and to determine what proportion of those perinatal deaths are directly attributable to vasa previa. DATA SOURCES/METHODS:The following databases have been searched from January 1, 1987, to January 1, 2023: PubMed, Scopus, Web of Science, and Embase. STUDY ELIGIBILITY CRITERIA/METHODS:Our study included all studies (cohort studies and case series or reports) that had patients in which a prenatal diagnosis of vasa previa was made. Case series or reports were excluded from the meta-analysis. All cases in which prenatal diagnosis was not made were excluded from the study. METHODS:. The publication bias was evaluated using a funnel plot and the Peters regression test. The Newcastle-Ottawa scale was used to assess the risk of bias. RESULTS:=0.0%) of pregnancies, respectively. CONCLUSION/CONCLUSIONS:Perinatal death is uncommon after a prenatal diagnosis of vasa previa. Approximately half of the cases of perinatal mortality are not directly attributable to vasa previa. This information will help in guiding physicians in counseling and will provide reassurance to pregnant individuals with a prenatal diagnosis of vasa previa.

Multisystem inflammatory syndrome in children (MIS-C), a new condition related to coronavirus disease 2019 (COVID-19) in the pediatric population, was recognized by physicians in the United Kingdom in April 2020. Given those up to the age of 21 years can be affected, pregnant adolescents and young adults are susceptible. However, there is scant information on how MIS-C may affect pregnancy and whether the presentation differs in the pregnant population. We report a case of a pregnant adolescent with COVID-19 and MIS-C with a favorable outcome. This case highlights the considerations in managing a critically ill pregnant patient with a novel illness and the importance of a multidisciplinary team in coordinating care.

BACKGROUND:Crown-rump length discordance, defined as ≥10% discordance, has been investigated as an early sonographic marker of subsequent growth abnormalities and is associated with an increased risk of fetal loss in twin pregnancies. Previous studies have not investigated the prevalence of fetal aneuploidy or structural anomalies in twins with discordance or the independent association of crown-rump length discordance with adverse perinatal outcomes. Moreover, data are limited on cell-free DNA screening for aneuploidy in dichorionic twins with discordance. OBJECTIVE:This study aimed to evaluate whether crown-rump length discordance in dichorionic twins between 11 and 14 weeks of gestation is associated with a higher risk of aneuploidy, structural anomalies, or adverse perinatal outcomes and to assess the performance of cell-free DNA screening in dichorionic twin pregnancies with crown-rump length discordance. STUDY DESIGN/METHODS:This was a secondary analysis of a multicenter retrospective cohort study that evaluated the performance of cell-free DNA screening for the common trisomies in twin pregnancies from December 2011 to February 2020. For this secondary analysis, we included live dichorionic pregnancies with crown-rump length measurements between 11 and 14 weeks of gestation. First, we compared twin pregnancies with discordant crown-rump lengths with twin pregnancies with concordant crown-rump lengths and analyzed the prevalence of aneuploidy and fetal structural anomalies in either twin. Second, we compared the prevalence of a composite adverse perinatal outcome, which included preterm birth at <34 weeks of gestation, hypertensive disorders of pregnancy, stillbirth or miscarriage, small-for-gestational-age birthweight, and birthweight discordance. Moreover, we assessed the performance of cell-free DNA screening in pregnancies with and without crown-rump length discordance. Outcomes were compared with multivariable regression to adjust for confounders. RESULTS:Of 987 dichorionic twins, 142 (14%) had crown-rump length discordance. The prevalence of aneuploidy was higher in twins with crown-rump length discordance than in twins with concordance (9.9% vs 3.9%, respectively; adjusted relative risk, 2.7; 95% confidence interval, 1.4-4.9). Similarly, structural anomalies (adjusted relative risk, 2.5; 95% confidence interval, 1.4-4.4]) and composite adverse perinatal outcomes (adjusted relative risk, 1.2; 95% confidence interval, 1.04-1.3) were significantly higher in twins with discordance. A stratified analysis demonstrated that even without other ultrasound markers, there were increased risks of aneuploidy (adjusted relative risk, 3.5; 95% confidence interval, 1.5-8.4) and structural anomalies (adjusted relative risk, 2.7; 95% confidence interval, 1.5-4.8) in twins with CRL discordance. Cell-free DNA screening had high negative predictive values for trisomy 21, trisomy 18, and trisomy 13, regardless of crown-rump length discordance, with 1 false-negative for trisomy 21 in a twin pregnancy with discordance. CONCLUSION/CONCLUSIONS:Crown-rump length discordance in dichorionic twins is associated with an increased risk of aneuploidy, structural anomalies, and adverse perinatal outcomes, even without other sonographic abnormalities. Cell-free DNA screening demonstrated high sensitivity and negative predictive values irrespective of crown-rump length discordance; however, 1 false-negative result illustrated that there is a role for diagnostic testing. These data may prove useful in identifying twin pregnancies that may benefit from increased screening and surveillance and are not ascertained by other early sonographic markers.

OBJECTIVE:One goal of prenatal genetic screening is to optimize perinatal care and improve infant outcomes. We sought to determine whether high-risk cfDNA screening for 22q11.2 deletion syndrome (22q11.2DS) affected prenatal or neonatal management. METHODS:This was a secondary analysis from the SMART study. Patients with high-risk cfDNA results for 22q11.2DS were compared with the low-risk cohort for pregnancy characteristics and obstetrical management. To assess differences in neonatal care, we compared high-risk neonates without prenatal genetic confirmation with a 1:1 matched low-risk cohort. RESULTS:Of 18,020 eligible participants enrolled between 2015 and 2019, 38 (0.21%) were high-risk and 17,982 (99.79%) were low-risk for 22q11.2DS by cfDNA screening. High-risk participants had more prenatal diagnostic testing (55.3%; 21/38 vs. 2.0%; 352/17,982, p < 0.001) and fetal echocardiography (76.9%; 10/13 vs. 19.6%; 10/51, p < 0.001). High-risk newborns without prenatal diagnostic testing had higher rates of neonatal genetic testing (46.2%; 6/13 vs. 0%; 0/51, P < 0.001), echocardiography (30.8%; 4/13 vs. 4.0%; 2/50, p = 0.013), evaluation of calcium levels (46.2%; 6/13 vs. 4.1%; 2/49, P < 0.001) and lymphocyte count (53.8%; 7/13 vs. 15.7%; 8/51, p = 0.008). CONCLUSIONS:High-risk screening results for 22q11.2DS were associated with higher rates of prenatal and neonatal diagnostic genetic testing and other 22q11.2DS-specific evaluations. However, these interventions were not universally performed, and >50% of high-risk infants were discharged without genetic testing, representing possible missed opportunities to improve outcomes for affected individuals.

BACKGROUND:The American College of Obstetricians and Gynecologists recommends all pregnant people be offered genetic screening and diagnostic testing regardless of risk factors. Previous studies have demonstrated disparities in referrals for genetic testing by race outside of pregnancy, but limited data exist regarding genetic counseling practices during pregnancy. OBJECTIVE:This study aimed to describe how patient, provider, and practice demographics influence the offering of diagnostic prenatal genetic testing by outpatient prenatal care providers. STUDY DESIGN:This was a multicenter anonymous survey study conducted between October 2021 and March 2022. Outpatient prenatal care providers, including family medicine and obstetrics attendings, residents, maternal-fetal medicine fellows, nurse practitioners, physician assistants, and midwives, were surveyed about their genetic counseling practices and practice demographics. The primary outcome was the proportion of respondents who answered "yes, all patients" to the survey question "Do you offer diagnostic genetic testing to all patients?" The secondary outcomes included the association between patient and practice demographics and offering diagnostic testing. Diagnostic testing was defined as chorionic villus sampling or amniocentesis. Screening genetic tests were defined as sequential screen, quadruple screen, cell-free DNA screening, or "other." The chi-square test or Fisher exact test was used as appropriate. For the outcome answers of diagnostic testing, logistic regression was performed to assess the association between the answer of diagnostic genetic testing and the current training level of providers, race and ethnicity, and insurance status variables. Multivariable analysis was performed to adjust for confounders. RESULTS:A total of 635 outpatient prenatal care providers across 7 sites were sent the survey. Overall, 419 providers responded for a total response rate of 66%. Of the providers who responded, most were attendings (44.9%), followed by residents (37.5%). Providers indicated the race, insurance status, and primary language of their patient population. Screening genetic testing was offered by 98% of providers. Per provider report, 37% offered diagnostic testing to all patients, 18% did not offer it at all, and 44% only offered it if certain patient factors were present. Moreover, 54.8% of attendings reported universally offering diagnostic testing. On univariable analysis, residents were less likely to offer diagnostic testing than attendings (odds ratio, 0.18; 95% confidence interval, 0.11-0.30). Providers who serve non-Hispanic Black, Hispanic Black, and other Hispanic patients were less likely to report offering diagnostic testing than other patient populations. Providers who served non-Hispanic Whites were more likely to offer diagnostic testing (odds ratio, 2.26; 95% confidence interval, 1.51-3.39). Patient populations who were primarily privately insured were more likely to be offered diagnostic testing compared with primarily publicly insured patients (odds ratio, 6.25; 95% confidence interval, 3.60-10.85). Providers who served a primarily English-speaking population were more likely to offer diagnostic genetic testing than other patient populations (odds ratio, 0.43; 95% confidence interval, 0.26-0.69). On multivariable analysis, the factors that remained significantly associated with offering diagnostic testing included level of training (resident odds ratio, 0.33; 95% confidence interval, 0.17-0.62; P=.0006; advanced practice provider odds ratio, 0.34; 95% confidence interval, 0.15-0.82; P=.02), having at least one-third of the patient population identify as "other Hispanic" (odds ratio, 0.42; 95% confidence interval, 0.23-0.77; P=.005), and having private insurance instead of public insurance (primarily private insured odds ratio, 2.84; 95% confidence interval, 1.20-6.74; P=.02). CONCLUSION:Although offering genetic screening and diagnostic testing to all patients is recommended, no provider group universally offers diagnostic testing. Providers who serve populations from a racial and ethnic minority, those with public insurance, and those whose primary language is not English are less likely to report universally offering diagnostic genetic testing.

BACKGROUND:Analysis of cell-free DNA from maternal blood provides effective screening for trisomy 21 in singleton pregnancies. Data on cell-free DNA screening in twin gestations are promising although limited. In previous twin studies, cell-free DNA screening was primarily performed in the second trimester and many studies did not report chorionicity. OBJECTIVE:This study aimed to evaluate the screening performance of cell-free DNA for trisomy 21 in twin pregnancies in a large, diverse cohort. A secondary aim was to evaluate screening performance for trisomy 18 and trisomy 13. STUDY DESIGN/METHODS:This was a retrospective cohort study of twin pregnancies from 17 centers for which cell-free DNA screening was performed from December 2011 to February 2020 by one laboratory using massively parallel sequencing technology. Medical record review was conducted for all newborns and data on the birth outcome, the presence of any congenital abnormalities, phenotypic appearance at birth, and any chromosomal testing that was undertaken in the antenatal or postnatal period were extracted. Cases with a possible fetal chromosomal abnormality with no genetic test results were reviewed by a committee of maternal-fetal medicine geneticists. Cases with a vanishing twin and inadequate follow-up information were excluded. A minimum of 35 confirmed cases of trisomy 21 was required to capture a sensitivity of at least 90% with a prevalence of at least 1.9% with 80% power. Test characteristics were calculated for each outcome. RESULTS:A total of 1764 samples were sent for twin cell-free DNA screening. Of those, 78 cases with a vanishing twin and 239 cases with inadequate follow-up were excluded, leaving a total of 1447 cases for inclusion in the analysis. The median maternal age was 35 years and the median gestational age at cell-free DNA testing was 12.3 weeks. In total, 81% of the twins were dichorionic. The median fetal fraction was 12.4%. Trisomy 21 was detected in 41 of 42 pregnancies, yielding a detection rate of 97.6% (95% confidence interval, 83.8-99.7). There was 1 false negative and no false positive cases. Trisomy 21 was detected in 38 out of 39 dichorionic twin pregnancies, yielding a detection rate of 97.4% (95% confidence interval, 82.6-99.7). Trisomy 18 was detected in 10 of the 10 affected pregnancies. There was 1 false positive case. Trisomy 13 was detected in 4 of the 5 cases, yielding a detection rate of 80% (95% confidence interval, 11.1-99.2). There was one false negative and no false positive cases. The nonreportable rate was low at 3.9 %. CONCLUSION/CONCLUSIONS:Cell-free DNA testing is effective in screening for trisomy 21 in twin gestations from the first trimester of pregnancy. Detection of trisomy 21 was high in dichorionic and monochorionic twins, and the nonreportable result rates were low. This study included high numbers of cases of trisomy 18 and 13 when compared with the current literature. Although screening for these conditions in twins seems to be promising, the numbers were too small to make definitive conclusions regarding the screening efficacy for these conditions. It is possible that cell-free DNA testing performance may differ among laboratories and vary with screening methodologies.

BACKGROUND:The clinical implications of nonreportable cell-free DNA screening results are uncertain, but such results may indicate poor placental implantation in some cases and be associated with adverse obstetrical and perinatal outcomes. OBJECTIVE:This study aimed to assess the outcomes of pregnancies with nonreportable cell-free DNA screening in a cohort of patients with complete genetic and obstetrical outcomes. STUDY DESIGN/METHODS:This was a prespecified secondary analysis of a multicenter prospective observational study of prenatal cell-free DNA screening for fetal aneuploidy and 22q11.2 deletion syndrome. Participants who underwent cell-free DNA screening from April 2015 through January 2019 were offered participation. Obstetrical outcomes and neonatal genetic testing results were collected from 21 primary-care and referral centers in the United States, Europe, and Australia. The primary outcome was risk for adverse obstetrical and perinatal outcomes (aneuploidy, preterm birth at <28, <34, and <37 weeks' gestation, preeclampsia, small for gestational age or birthweight <10th percentile for gestational week, and a composite outcome that included preterm birth at <37 weeks, preeclampsia, small for gestational age, and stillbirth at >20 weeks) after nonreportable cell-free DNA screening because of low fetal fraction or other causes. Multivariable analyses were performed, adjusting for variables known to be associated with obstetrical and perinatal outcomes, nonreportable results, or fetal fraction. RESULTS:In total, 25,199 pregnant individuals were screened, and 20,194 were enrolled. Genetic confirmation was missing in 1165 (5.8%), 1085 (5.4%) were lost to follow-up, and 93 (0.5%) withdrew; the final study cohort included 17,851 (88.4%) participants who had cell-free DNA, fetal or newborn genetic confirmatory testing, and obstetrical and perinatal outcomes collected. Results were nonreportable in 602 (3.4%) participants. A sample was redrawn and testing attempted again in 427; in 112 (26.2%) participants, results were again nonreportable. Nonreportable results were associated with higher body mass index, chronic hypertension, later gestational age, lower fetal fraction, and Black race. Trisomy 13, 18, or 21 was confirmed in 1.6% with nonreportable tests vs 0.7% with reported results (P=.013). Rates of preterm birth at <28, 34, and 37 weeks, preeclampsia, and the composite outcome were higher among participants with nonreportable results, and further increased among those with a second nonreportable test, whereas the rate of small for gestational age infants was not increased. After adjustment for confounders, the adjusted odds ratios were 2.2 (95% confidence interval, 1.1-4.4) and 2.6 (95% confidence interval, 0.6-10.8) for aneuploidy, and 1.5 (95% confidence interval, 1.2-1.8) and 2.1 (95% confidence interval, 1.4-3.2) for the composite outcome after a first and second nonreportable test, respectively. Of the patients with nonreportable tests, 94.9% had a live birth, as opposed to 98.8% of those with reported test results (adjusted odds ratio for livebirth, 0.20 [95% confidence interval, 0.13-0.30]). CONCLUSION/CONCLUSIONS:Patients with nonreportable cell-free DNA results are at increased risk for a number of adverse outcomes, including aneuploidy, preeclampsia, and preterm birth. They should be offered diagnostic genetic testing, and clinicians should be aware of the increased risk of pregnancy complications.

PURPOSE/OBJECTIVE:To assess the performance of cell-free DNA (cfDNA) screening to detect sex chromosome aneuploidies (SCA) in an unselected obstetrical population with genetic confirmation. METHODS:This was a planned secondary analysis of the multicenter, prospective SMART study. Patients receiving cfDNA results for autosomal aneuploidies and who had confirmatory genetic results for the relevant sex chromosomal aneuploidies were included. Screening performance for SCAs, including monosomy X (MX) and the sex chromosome trisomies (SCTs; 47,XXX; 47,XXY; 47,XYY) was determined. Fetal sex concordance between cfDNA and genetic screening was also evaluated in euploid pregnancies. RESULTS:17,538 cases met inclusion criteria. Performance of cfDNA for MX, SCTs and fetal sex was determined in 17,297, 10,333 and 14,486 pregnancies, respectively. Sensitivity, specificity, and PPV of cfDNA were 83.3%, 99.9%, and 22.7% for MX, and 70.4%, 99.9%, and 82.6% for the combined SCTs. The accuracy of fetal sex prediction by cfDNA was 100%. CONCLUSION/CONCLUSIONS:Screening performance of cfDNA for SCAs is comparable to that reported in other studies. The PPV for the SCTs was similar to the autosomal trisomies, while the PPV for MX was substantially lower. No discordance in fetal sex was observed between cfDNA and postnatal genetic screening in euploid pregnancies. These data will assist interpretation and counseling for cfDNA results for sex chromosomes.

Objective: Reticulocyte hemoglobin (RetHb) is used for early detection of iron deficiency (ID) in the nonpregnant patient population. It provides an indication of iron availability in the bone marrow and is an early marker of iron deficiency (ID) erythropoiesis before anemia is present. Due to the paucity of data regarding RetHb use in pregnancy, the study objective was to establish normal values and trend for RetHb during the 1^st and 2^nd trimester of pregnancy by correlating it with ferritin and Hb.
Study Design: This is a secondary analysis of an observational, prospective cohort study evaluating ID parameters in singleton gestations presenting for prenatal care in the first trimester from 2/2022 to 6/2022. ID was defined as serum ferritin level of <= 29 ng/mL. For this analysis, patients were excluded if they had 1^st trimester anemia (Hb< 11.0 g/dL) or history of blood transfusion 3 months prior to pregnancy. Data were analyzed using student's t-test and linear regression modeling with statistical significance defined at p< 0.05.
Result(s): 209 patients met inclusion criteria. In table 1, demographics of the study cohort are shown. There was a prevalence of 16.3% of ID in the 1^st trimester and 69.9% in the 2^nd trimester. Distribution of RetHb values throughout the first 2 trimesters are demonstrated in figure 1. In the 1^st trimester, the mean RetHb in women with ID was 34.01 pg +/- SD 1.64 compared to 34.68 pg +/- 1.65 in women without iron deficiency (p=0.03). In the second trimester, the mean RetHb in women with ID was 33.02 pg +/- 2.34 compared to 34.20 pg +/- SD 1.94 in women without ID (p< 0.001).
Conclusion(s): A statistically significant physiologic decrease was observed among pregnant individuals both with and without iron deficiency in the first and second trimester of pregnancy. Future studies should evaluate the utility of RetHb use in pregnancy to predict ID and iron deficiency anemia throughout pregnancy. [Formula presented] [Formula presented]
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