Monica Flessel

Risk of selected structural abnormalities in infants after increased nuchal translucency measurement

OBJECTIVE We sought to examine the association between increased first-trimester fetal nuchal translucency (NT) measurement and major noncardiac structural birth defects in euploid infants. STUDY DESIGN Included were 75,899 singleton infants without aneuploidy or critical congenital heart defects born in California in 2009 through 2010 with NT measured between 11-14 weeks of gestation. Logistic binomial regression was employed to estimate relative risks (RRs) and 95% confidence intervals (CIs) for occurrence of birth defects in infants with an increased NT measurement (by percentile at crown-rump length [CRL] and by ≥3.5 mm compared to those with measurements <90th percentile for CRL). RESULTS When considered by CRL adjusted percentile and by measurement ≥3.5 mm, infants with a NT ≥95th percentile were at risk of having ≥1 major structural birth defects (any defect, RR, 1.6; 95% CI, 1.3-1.9; multiple defects, RR, 2.1; 95% CI, 1.3-3.4). Infants with a NT measurement ≥95th percentile were at particularly high risk for pulmonary, gastrointestinal, genitourinary, and musculoskeletal anomalies (RR, 1.6-2.7; 95% CI, 1.1-5.4). CONCLUSION Our findings demonstrate that risks of major pulmonary, gastrointestinal, genitourinary, and musculoskeletal structural birth defects exist for NT measurements ≥95th percentile. The ≥3-fold risks were observed for congenital hydrocephalus; agenesis, hypoplasia, and dysplasia of the lung; atresia and stenosis of the small intestine; osteodystrophies; and diaphragm anomalies.

Integrated and first trimester prenatal screening in California: program implementation and patient choice for follow‐up services

The California Prenatal Screening Program serves over 350 000 women annually. This study examines utilization rates for the various screening options and patient choices regarding follow‐up services.

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. RESULTS: Of 452,901 women screened, 17,435 (3.8%) were screen-positive for Down syndrome only; 433 (0.1%) for trisomy 18 only; 1,689 (0.4%) for both Down syndrome and trisomy 18; and 2,947 (0.7%) for neural tube defects, Smith-Lemli-Opitz syndrome, or for multiple conditions. The detection rates were Down syndrome—92.9% (95% confidence interval [CI] 91.4–94.2); trisomy 18—93.2% (95% CI 90.5–95.9); trisomy 13—80.4% (95% CI 73.9–86.9); 45,X—80.1% (95% CI 73.9–86.3), and triploidy—91.0% (95% CI 84.2–97.9). Overall, the detection rate for chromosome abnormalities was 81.6% (95% CI 80.0–83.1) at an overall false-positive rate of 4.5%. CONCLUSION: First-trimester and sequential screening are sensitive and specific for the broad range of karyotype abnormalities seen in the population. LEVEL OF EVIDENCE: II

Detection rate of quadruple‐marker screening determined by clinical follow‐up and registry data in the statewide California program, July 2007 to February 2009

To evaluate the efficiency of Californias quadruple‐marker screening program and construct receiver‐operating characteristic (ROC) curves.

Obstetric, perinatal, and fetal outcomes in pregnancies with false-positive integrated screening results.

OBJECTIVE: To assess the risk of adverse obstetric, perinatal, and fetal outcomes for pregnant women participating in prenatal sequential integrated screening through the California Prenatal Screening Program who had a false-positive screening result. METHODS: Women who underwent first- and second-trimester prenatal integrated screening plus nuchal translucency measurement with outcome information available were included. Fetuses and neonates with chromosomal or neural tube defects were excluded. We compared the risk of adverse outcomes for all women with a positive screening result compared with a 10% random sample of women with a negative screening result. Logistic binomial regression was used to compare adverse outcomes in screen-positive compared with screen-negative women. RESULTS: We identified 9,051 screen-positive and 30,928 screen-negative pregnancies with outcome information available. Compared with screen-negative pregnancies, screen-positive women were more likely to be diagnosed with preeclampsia, placenta previa, or abruption (7.6% screen-positive, 3.8% screen-negative; relative risk 1.7, 95% confidence interval [CI] 1.6–1.8) or experience fetal loss before 20 weeks of gestation (1.9% screen-positive, 0.2% screen-negative; relative risk 3.5, 95% CI 3.2–3.8). Women with positive results for more than one screened condition were at substantially greater risk of fetal and neonatal mortality (relative risks 33.6–156.7, 95% CIs 21.8–194.4). CONCLUSION: Among pregnancies without chromosomal or neural tube defects, prenatal sequential integrated screening provides information regarding risk across a variety of adverse pregnancy outcomes. LEVEL OF EVIDENCE: II

The California Prenatal Screening Program: “Options and choices” not “coercion and eugenics”

The California Prenatal Screening Program is designed to make prenatal screening available to the states large and diverse population. The Program provides information to women which will allow them to make informed choices regarding prenatal screening and prenatal diagnosis. Since the Programs inception in 1986, women in California have had the option to participate in prenatal screening or to decline prenatal screening. The California Program offers prenatal diagnostic services to women whose screening tests indicate an increased risk for birth defects, including Down syndrome. Women can decline any or all of these follow-up services. Genetic counseling, diagnostic services, and the presentation of diagnostic results are performed by medical professionals (not State staff) who follow established guidelines for nondirective counseling. Program data clearly demonstrate that women in California have a wide range of options and make a wide range of choices regarding prenatal screening and prenatal diagnosis. Californias comprehensive Prenatal Screening Program promotes optimal care for all women within all options and choices. The important and necessary communication among organizations and stakeholders involved in prenatal screening and diagnosis, and in related care for pregnant women and for people with Down syndrome, is not served by misrepresentation and inflammatory rhetoric.

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. Pregnancies conceived with ovum donation and women older than 45 years were excluded. We compared the observed Down syndrome incidence per pregnancy for twins with expected incidence by extrapolating from singleton data and expected zygosity as is the current clinical approach. This extrapolation assumes that monozygotic pregnancies have equivalent Down syndrome risk per pregnancy relative to maternal age–matched singletons and dizygotic pregnancies have twice the risk of at least one affected fetus. Zygosity for affected cases was presumed to be monozygotic with Down syndrome concordance and dizygotic with Down syndrome discordance. Counts were compared using cumulative Poisson distributions. RESULTS: Of 77,279 twin pregnancies, 182 (0.2%) had at least one fetus with Down syndrome confirmed by karyotype. The ratio of observed-to-expected Down syndrome incidence per pregnancy was 33.6%, 75.2%, and 70.0% for monozygotic, dizygotic, and all twins, respectively (P<.001 for all comparisons). Considering maternal age subgroups and twin zygosity, a significantly lower-than-expected Down syndrome incidence was seen for women aged 25 to 45 years with monozygotic pregnancies and overall for women aged 25 to 45 years with dizygotic pregnancies. CONCLUSION: The observed incidence of Down syndrome in twin pregnancies is lower than expected, most notably for monozygotic pregnancies and with increasing maternal age. Risk-based counseling can strongly affect womens choices regarding testing and management during pregnancy, so an understanding of the true Down syndrome risk in twin gestations is crucial.

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

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