Faculty Bibliography

OBJECTIVE: Fetal reduction (FR) in multiples dramatically improves outcomes. We prioritize FR decisions for health and historically declined to factor gender. As male preferences apparently diminished, our bioethicist encouraged a re-evaluation. METHODS: Three hundred ninety-six patients reducing triplets or twins were categorized as 32, 31, and 21, Major (M) anomaly or minor (m) anomaly, same gender (SG), and those for whom gender preference (GP) was possible. Higher order and non chorionic villus sampling were excluded. FR decisions were prioritized by M anomaly, Suspicious, or m anomaly. If neither, we considered GP. RESULTS: Of 319, 214 (67%) had either M/m or SG. Of those, 32 with gender option: 71/79 chose male and female or had no preferences, one chose male/male, and seven chose female/female. We reduced monochorionic twins in 33/35 31 cases. Of 20 with GP choice, 10 chose male and 10 chose female. Of 162 21, 54 had M or m, 50 were SG, but of the 44 M/F twins, 20 chose male and 24 chose female. CONCLUSIONS: There has been a cultural shift mostly preferring one of each or having no preference. When reducing to one, >50% prefer a girl. In addition to identifying abnormalities, chorionic villus sampling before FR expands patient autonomy.

OBJECTIVE: To examine the ability of chorionic villus sampling (CVS) and fluorescence in situ hybridization (FISH) to detect aneuploidy before first trimester fetal reduction (FR) in sonographically normal-appearing fetuses. METHODS: A retrospective review of 470 patients referred to our unit for FR from January 2007-March 2011. Prenatal diagnosis was offered to all. FR was performed after next-day FISH results. Abnormalities were categorized by ultrasound, FISH, and/or karyotype. Sensitivity, specificity, positive predictive value, and negative predictive value of pre-FR FISH were calculated. RESULTS: Four hundred thirty-two of 470 patients seen were first trimester. 24/432 (5.2%) were excluded for abnormal ultrasound findings, including nuchal translucency (NT) > 3.0 mm, and 360 (88.2%) underwent CVS before FR. Ten fetuses were then excluded for euploid sex mosaicism. 10/350 (2.9%) patients with normal ultrasounds had abnormal FISH confirmed by karyotype. 9/350 (2.6%) patients with normal FISH had an abnormal karyotype necessitating follow up amniocentesis in which the clinically relevant discordancy was confirmed in one case (1/350, 0.3%). Pre-FR FISH had a 90% sensitivity, 99.4% specificity, 83.3% positive predictive value, and 99.7% negative predictive value. CONCLUSIONS: 3.1% of patients with normal-appearing fetuses prior to first trimester FR had a fetus with an abnormal karyotype of which FISH detected 90%. CVS with FISH prior to FR adds significant information that can guide reduction decisions.