380: Fascia lata versus placental specimens for genetic testing after IUFD: success rates and financial cost

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Fascia lata and placental specimens are commonly collected for genetic testing of fetal cells after intrauterine fetal demise (IUFD). ACOG guidelines recommend collection of placental specimens over fascia lata, as placenta has better tissue culture success rates. However, at many institutions, fascia lata for IUFDs continues to be collected routinely. This study compares success rates and financial costs of these two tissue sources in providing viable cells for karyotype analysis after IUFD. A retrospective chart review was performed for patients with a diagnosis of IUFD admitted to a single academic institution from 2015 to 2017. We identified patients for which fetal fascia lata and/or placental specimen was collected for karyotyping. For each case, data concerning karyotype success rates (defined as fetal cell growth sufficient to undergo karyotype analysis), training level of collecting provider, time from IUFD diagnosis to sample collection, and cost of laboratory testing were extracted. Charts from 71 patients with a diagnosis of IUFD were reviewed. In total, 35 placental specimens and 14 fascia lata specimens were collected. Of these samples, 80% of the placental and 21% of the fascia lata samples successfully grew cells for karyotype (p=<0.01). In cases where both fascia lata and placental specimens were collected, there were no instances where the fascia lata successfully yielded cells for karyotype when the placental specimen was unsuccessful. There was no difference in karyotype success rates when comparing specimens collected by more experienced providers (more than 2 years of training) or less experienced providers (p=0.29; RR=0.77; CI=0.47-1.3). Time from diagnosis to sample collection was not predictive of karyotype success rates in this study. Cost of tissue culture and karyotyping was $2,151 for either a placental or fascia lata specimen, or $4,302 for both. At our institution, placental samples have a significantly higher karyotype success rate compared to fascia lata specimens, regardless of provider experience or time from diagnosis to sample collection. This study supports the prioritization of placental specimen collection over fascia lata, especially in settings where routine amniocentesis for IUFD is unavailable. This study also shows that there is a significant cost saving without benefit loss in collecting only placental specimens compared to collecting both fascia lata and placental samples.