The effects of heparin, aspirin, and maternal clinical factors on the rate of nonreportable cell-free DNA results: a retrospective cohort study.

BACKGROUND: Technological advances in the analysis of cell-free DNA in maternal serum have allowed expanded prenatal screening possibilities for fetal aneuploidies. The sensitivity and positive predictive value of the assay are partly dependent on the amount of cell-free DNA present in maternal circulation. Thus, it is important to know what fetal and maternal factors influence the level of cell-free DNA in maternal circulation. Maternal heparin use has been associated with an increase in nonreportable cell-free DNA results because of a low fetal fraction in some, but not all, previous studies. In addition, there are likely additional factors that affect cell-free DNA that remain uncharacterized. OBJECTIVE: This study aimed to determine whether heparins, low-dose aspirin, and maternal clinical factors affect the rate of nonreportable cell-free DNA testing results. STUDY DESIGN: A retrospective cohort study was conducted using pregnant people receiving cell-free fetal DNA testing from January 1, 2014, to June 30, 2018. Data were collected on patient demographics, medical comorbidities, medication use, and cell-free DNA test results. Univariate and multivariate analyses were performed to determine which factors were independently associated with the rate of nonreportable results. RESULTS: From an original sample of 1117 pregnant people, 743 met the inclusion criteria. Maternal weight (odds ratio, 1.02), heparin use (odds ratio, 12.06), aspirin use (odds ratio, 4.70), chronic hypertension (odds ratio, 5.26), pregestational diabetes mellitus (odds ratio, 2.46), and autoimmune disease (odds ratio, 3.59) were significantly associated with an increased rate of nonreportable results in the univariate analysis. Moreover, the association was present for maternal weight (odds ratio, 1.02), heparin use (odds ratio, 21.87),and aspirin use (odds ratio, 2.85) in the multivariate analysis. CONCLUSION: The previously seen association between maternal heparin use and an increase in nonreportable cell-free DNA results was confirmed. Furthermore, there seems to be an increase in nonreportable results in pregnant people taking low-dose aspirin. Providers should consider the effect of these medications when counseling patients on prenatal genetic screening options.

Impact of pre-pregnancy obesity on cesarean delivery rates in nulliparous pregnant people undergoing induction of labor.

OBJECTIVE: To evaluate the impact of pre-pregnancy obesity on the cesarean delivery rate in nulliparous pregnant people undergoing induction of labor. STUDY DESIGN: This is a retrospective cohort study of nulliparous pregnant people with a normal weight and obesity who underwent induction of labor between 37 and 41 weeks gestation at a single institution from 2012 to 2018. Weight category was based on pre-pregnancy body mass index. The primary outcome was rate of cesarean delivery. Additional demographic and clinical characteristics were analyzed. A chi square test was used to compare the cesarean delivery rates. Multivariate logistic regression was used to generate adjusted odds ratios (aOR) and 95% confidence intervals (CI) controlling for potential cofounders. RESULTS: Of the 557 pregnancies identified, 88/285 (31%) of pregnant people with a normal weight had a cesarean delivery while 165/263 (63%) of pregnant people with obesity had a cesarean delivery (cOR 3.8, 95% CI 2.6-5.4). After adjustment, pregnant people with obesity remained more likely to have a cesarean delivery compared to pregnant people with a normal weight (aOR 2.7, 95% CI 1.8-4.0). Further, cesarean delivery was more likely in those with an unfavorable modified Bishop score (aOR 3.4, 95% CI 1.8-6.5) and gestational weight gain above the Institute of Medicine recommendation (aOR 2.6, 95% CI 1.8-3.9). The rate of cesarean delivery was not different by class of obesity (p = .32). CONCLUSION: Pre-pregnancy obesity is associated with higher cesarean delivery rates in nulliparous pregnant people undergoing induction of labor compared with normal pre-pregnancy body mass index. Gestational weight gain above the Institute of Medicine recommendations and having an unfavorable modified Bishop score at the time of induction are associated with increased cesarean delivery rates.

Continued Validation of Ultrasound Guidance Targeting Tasks: Relationship with Procedure Performance.

RATIONALE AND OBJECTIVES: To determine if deliberative practice with novel ultrasound guidance targeting tasks improves simulated procedural skill. MATERIALS AND METHODS: In a nonrandomized interventional trial first year medical students practiced the previous described dowel and straw targeting tasks 1 hour a week for 4 weeks (training group) or had no training (controls). Afterward, they each performed a simulated amniocentesis (AMN) and chorionic villus sampling (CVS) procedure. Procedures were scored using a global rating scale (GRS) and compared between groups with Mann-Whitney U tests. Two-way random effects intraclass correlation coefficients for the inter- and intra-rater variability were calculated for each item in both GRS's. RESULTS: The training group (n = 22) had higher scores on several aspects and overall performance of AMN compared to controls (n = 15). There were no differences between groups for CVS. The inter-rater and intra-rater reliability of the GRS's for both AMN and CVS ranged from 0.16 to 0.89 with most values demonstrating good to excellent agreement. CONCLUSION: This study demonstrates validity evidence in the content and internal structure domains for the AMN and CVS simulators and their accompanying GRS's. Repetitive practice of the targeting tasks improved student performance in simulated AMN, but modifications are needed for it to be relevant to other procedures such as CVS.