The utility of nuchal translucency ultrasound in identifying rare chromosomal abnormalities not detectable by cell-free DNA screening.

Objective:: To evaluate the utility of nuchal translucency (NT) screening in the detection of rare chromosomal aneuploidies in the setting of cell-free DNA (cfDNA).

Methods:: A retrospective cohort study of pregnancies screened through the California Prenatal Screening Program between March 2009 and December 2012. Karyotype analysis was the primary method of chromosomal evaluation during the study period and abnormal chromosomal karyotype results were classified by whether the abnormality would be detectable by cfDNA (non-mosaic trisomy 13, 18, 21 or sex-chromosomal aneuploidy (SCA)).

Observed Rate of Down Syndrome in Twin Pregnancies.

Objective: To evaluate the observed incidence of Down syndrome in twins compared with that expected based on maternal age-matched singletons, which is the current clinical approach.

Methods: This was a retrospective review of California Prenatal Screening Program participants with expected delivery dates between July 1995 and December 2012. Cases confirmed prenatally or postnatally with a genetic imbalance leading to phenotypic Down syndrome (trisomy 21, mosaic trisomy 21, or translocations) were included.

Racial-ethnic differences in midtrimester maternal serum levels of angiogenic and antiangiogenic factors.

Background: Little is known about racial-ethnic differences in the distribution of maternal serum levels of angiogenic and antiangiogenic factors and their associations with early-onset preeclampsia.

Objective: We sought to investigate the distribution of midtrimester maternal serum levels of placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor 1 and their associations with early-onset preeclampsia in whites, Hispanics, and blacks.

Study Design: A population-based nested case-control design was used to identify cases and controls of white, Hispanic, and black origin from a 2000 through 2007 live-birth cohort in 5 southern California counties.

Detection Rates for Aneuploidy by First-Trimester and Sequential Screening.

Objective: To estimate detection rates for aneuploidy by first-trimester and sequential screening.

Methods: The study included women with singleton pregnancies who participated in the California Prenatal Screening Program with estimated delivery dates from August 2009 to December 2012 who had first- or first- and second-trimester (sequential) screening. Detection rates were measured for target (trisomies 21 and 18) and other aneuploidies identified from the California Chromosome Defect Registry.

Outcomes of pregnancies with more than one positive prenatal screening result in the first or second trimester.

Objective: To describe adverse outcomes and fetal abnormalities in women with a positive prenatal screening result for more than one disorder.

Study Design: Study participants were drawn from a population of 452 901 women pregnant with singletons entering the California Prenatal Screening Program in their first-trimester. Risk assessment was provided for trisomy 21 and trisomy 18 in the first-trimester and trisomy 21, trisomy 18, neural tube defects, and Smith-Lemli-Opitz syndrome in the second-trimester.