229: Comparing invasive testing and pregnancy termination rates among patients following abnormal first trimester screen or non-invasive prenatal screen

Poster Session I pathologic microdeletions or duplications. The goal of this study was to investigate the cost-effectiveness of using different prenatal screening/diagnostic approaches for low risk women. STUDY DESIGN: A decision-analytic model was created to compare the use of amniocentesis with array, NIPT using cfDNA, and sequential screening in a theoretical cohort of 1,000,000 pregnancies at baseline low risk for aneuploidy. All probabilities, costs, and utilities were derived from the literature. The primary outcome was the incremental cost per quality-adjusted life year (QALY). Neonatal morbidity, termination, and procedure-related loss were also investigated for each screening technique. The cost-effectiveness threshold was set at $100,000 per QALY. Univariate and multivariate sensitivity analyses were used to investigate model robustness. RESULTS: Routine use of amniocentesis with microarray resulted in improved detection of fetal chromosomal abnormalities, including microdeletions (Table 1). Compared to sequential sequencing, amniocentesis with array would lead to 517 fewer births with a common trisomy and 10,423 fewer births affected by clinically significant copy number variations (CNVs). Amniocentesis with array would improve effectiveness by 4,288 QALYs compared to sequential screening and 4,408 QALYs compared to cfDNA and would save $11.4 billion (dominant strategy of lower costs and better outcomes). This advantage was maintained as termination rates for all aneuploidies and CNVs were varied through plausible ranges and as the cost of cfDNA was varied down to $0. The model remained robust when the probability of a CNV was above 0.00085. CONCLUSION: For detection of chromosomal abnormalities in lowrisk women, amniocentesis with microarray is a cost-effective strategy for detection of fetal chromosomal abnormalities compared to other screening modalities. Women should be offered the full range of prenatal diagnostic options and, given the cost-saving nature of this technology, there should be considerations for routine insurance coverage.

ajog.org 229 Comparing invasive testing and pregnancy termination rates among patients following abnormal first trimester screen or non-invasive prenatal screen Guadalupe Herrera-Garcia, Christina Duzyj, Elena Ashkinadze Rutgers Robert Wood Medical School, New Brunswick, NJ

OBJECTIVE: Traditional first trimester screening (FTS) has a higher

false positive rate, lower detection rate and lower positive predictive value compared to non-invasive prenatal screening (NIPS) using cell free DNA technology. We compared rates of invasive testing and pregnancy termination among patients who had primary aneuploidy screening by FTS or NIPS. STUDY DESIGN: We performed a retrospective cohort study, comparing patients who had FTS between November 2008 thru October 2011 (n¼2161) prior to the availability of NIPS against patient having NIPS in our office from November 2011-March 2016 (n¼2648). Chi square and Fishers exact statistics were performed as appropriate. RESULTS: In the designated time intervals, there were 67 abnormal FTS and 56 abnormal NIPS results (3 vs 2%, p¼0.018). Of the FTS and NIPS with elevated risk, 26 and 24 patients opted to have diagnostic testing (39 vs 43%, p¼0.199). Cases of abnormal NIPS opted for invasive testing in 21 cases of traditional aneuploidy and 3 cases of sex chromosome aneuploidy (54% vs. 18%, p¼0.0181). Invasive testing confirmed 2 cases of abnormal FTS and 21 of cases of abnormal NIPS (8 vs 88%, p¼0.0005). Of the confirmed traditional aneuploidy cases 1 FTS case and 16 NIPS cases opted for termination (50% vs 76%, p¼1). Of NIPS cases opting for termination, 16 were for traditional aneuploidy and 1 for sex chromosome aneuploidy (84% vs 50%, p¼ 0.3524). CONCLUSION: Primary screening modality did not change patient decision to undergo invasive testing or termination of pregnancy. None of the patients opted for termination of pregnancy without first undergoing confirmatory testing. The choice to confirm NIPS, but not the choice to terminate a pregnancy differed based on whether traditional or sex chromosome aneuploidy was found.

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Poster Session I

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trimester. Additionally, women with MSAFP  2.07 MoM have a higher likelihood of having elevated levels in the second trimester though the positive predictive value is low. First trimester MSAFP may be utilized to assess women at risk for adverse pregnancy outcomes that are known to be associated with elevations in the second trimester.

230 Do elevated first-trimester maternal serum alpha-fetoprotein (MSAFP) levels predict elevated second trimester levels? Sarah L. Pachtman1, Hima Tam Tam1, David Krantz2, Matthew Blitz1, Kiran Tam Tam3 1 Hofstra-Northwell School of Medicine, Division of Maternal-Fetal Medicine, Manhasset, NY, 2Eurofins/NTD Laboratories, Melville, NY, 3Baylor College of Medicine, Division of Maternal-Fetal Medicine, Houston, TX

OBJECTIVE: To determine if elevated MSAFP levels in the first

trimester predict elevation in the second trimester. STUDY DESIGN: Retrospective cohort study in women who underwent

both first and second trimester serum screening tests at North Shore University Hospital in Manhasset, NY between April 2015 and June 2016. Maternal samples were analyzed by PerkinElmer/NTD Labs. Multiple gestations were excluded. Demographic data including maternal weight, age, ethnicity, smoking status, valproic acid and assisted reproductive technology use were collected. An elevated second-trimester MSAFP was defined as a value  2.5 multiple of the median (MoM). The optimal cut-point of first-trimester MSAFP MoM to predict a second-trimester MSAFP of 2.5 MoM was derived from a receiver operating characteristic (ROC) curve by selecting the point of highest sensitivity and specificity. Accuracy of first-trimester MSAFP to predict an elevated second-trimester MSAFP was assessed by calculating the area under the curve (AUC) of the ROC. RESULTS: A total of 6700 subjects were included. Subject demographics are displayed in Table 1. The optimal cut-point for firsttrimester MSAFP was determined to be 2.07 MoM, which yielded a sensitivity of 75% (95% CI 60 - 85%) and specificity of 95% (95% CI 92 - 94%) for prediction of elevation in the second trimester. First trimester MSAFP  2.07 MoM has a negative predictive value of 99.8% for elevated second trimester MSAFP. AUC was 0.94, indicating that a first trimester MSAFP of  2.07 MoM was able to identify patients who would have a second-trimester MSAFP of  2.5 MoM. CONCLUSION: Given the established clinical significance of MSAFP, the ability to predict second trimester elevation through screening in the first trimester has important utility. Women with MSAFP values  2.07 MoM are unlikely to have elevated values in the second

231 Accuracy of initial genetic history screening in patients referred by general obstetricians for genetic counseling Marisa Gilstrop, Stephanie Corsetti, Vanita Jain, Phillip Shlossman, Anthony Sciscione Christiana Care Health System, Wilmington, DE

OBJECTIVE: ACOG guidelines recommend screening for prenatal assessment of familial genetic disease and/or aneuploidy testing early in the first trimester. We sought to determine the rate of missed genetic information in the general obstetrician office setting. STUDY DESIGN: This is a sequential case series of women referred for genetic counseling (GC) between 3/15-8/15 to a tertiary care, academic MFM practice. Once referred, all women completed a genetic intake form created by certified genetic counselors followed by inperson GC including pedigree generation. The prenatal record was reviewed for genetic history obtained by the referring provider, most

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