First trimester identification of fetal sex by ultrasound.

PURPOSE: The hypothesis was fetal sex determination by ultrasound at 11-14 weeks' gestation has sufficient accuracy to be clinically relevant. METHODS: Fetal sex assessment by transabdominal ultrasound was performed in 567 fetuses at 11-14 weeks' gestation (CRL: 45-84 mm). A mid-sagittal view of the genital region was obtained. The angle of the genital tubercle to a horizontal line through the lumbosacral skin surface was measured. The fetus was assigned male sex if the angle was > 30°, and female sex if the genital tubercle was parallel or convergent (< 10°). At an intermediate angle of 10-30°, the sex was not assigned. The results were divided into three categories based on gestational age: 11 + 2 to 12 + 1, 12 + 2 to 13 + 1, and 13 + 2 to 14 + 1 weeks' gestation. To establish its accuracy, the first trimester fetal sex determination was compared to fetal sex determined on a mid-second trimester ultrasound. RESULTS: Sex assignment was successful in 534/683 (78%) of the cases. The overall accuracy of fetal sex assignment across all gestational ages studied was 94.4%. It was 88.3%, 94.7%, and 98.6% at 11 + 2 to 12 + 1, 12 + 2 to 13 + 1, and 13 + 2 to 14 + 1 weeks' gestation, respectively. CONCLUSION: Prenatal sex assignment at the time of first trimester ultrasound screening has a high accuracy rate. The accuracy improved with increasing gestational age, which suggests that if clinically important decisions, such as chorionic villus sampling, are to be made based on fetal sex, they should be delayed until the latter part of the first trimester.

A pragmatic evaluation of the implementation and acceptance of a universal second trimester cervical length screening program in an un-selected population.

PURPOSE: To evaluate patients' acceptance of a universal transvaginal ultrasound cervical length (CL) screening program and the feasibility of initiating treatment with progesterone in a clinical setting in women found to have a short cervix. METHODS: An observational, pragmatic cohort study was conducted at one tertiary care facility from 2012-2015, involving eligible women with singleton pregnancies who accepted and underwent second-trimester CL screening. The primary outcomes were the percentage of women who were eligible and accepting of screening, compliance with progesterone treatment, and the screening value of TVCL in predicting SPTB. Secondary outcomes were the number of women who received progesterone treatment and the rates of SPTB. RESULTS: Overall cervical length screening acceptance rate was found to be 82.5%. Of the 797 women that underwent screening, 21 women (2.6%) had a TVCL < 25 mm, of whom nine had a TVCL < 20.0 mm. Nineteen of the 21 women with a TVCL < 25 mm were treated with progesterone, with a 94.7% compliance rate. Delivery outcomes were obtained for 767 women. Of those with a TVCL < 25 mm, there was a 35% rate of SPTB as opposed to a 6.3% SPTB rate in those with TVCL > 25 mm. The negative predictive value for SPTB with a TVCL 25 mm or greater was 94.0%. CONCLUSION: Universal cervical length screening was successfully implemented in 82.5% of the patient population with a high compliance rate with progesterone treatment. Furthermore, there was a higher rate of SPTB in those with a shorter cervix. Based on our outcomes obtained in an observational and pragmatic manner, we showed that incorporating second trimester transvaginal cervical length screening into routine clinical practice is readily accepted and, with the addition of vaginal progesterone treatment, may reduce the rate of prematurity.

Fetal eye ultrasound: Normal anatomy, abnormal findings, and clinical impact. / Ultraschall des fetalen Auges: Normale Anatomie, abnorme Befunde und klinische Bedeutung.

Until now, ultrasound examination of the fetal eyes has not played an important role in prenatal diagnosis. National and international guidelines are generally confined to documentation of the presence of the orbits and the lenses. However, in recent years, with the advent of high-resolution ultrasound technology and increasing knowledge of prenatal medicine and genetics, careful examination of the fetal eye has enabled the detection of many ocular malformations before birth. This article provides an overview of the anatomy related to the development of the fetal eye and covers the following conditions: hypertelorism, hypotelorism, exophthalmos, microphthalmos, coloboma, cataract, persistent hyperplastic primary vitreous, retinal detachment, dacryocystocele, and septooptic dysplasia, etc. It is designed to illustrate the spectrum of ocular malformations and their appearance on prenatal ultrasound and to discuss their clinical impact and association with various syndromes.

Screen-positive rate in cell free DNA screening for trisomy 21.

OBJECTIVE: To assess whether the fetal fraction (FF) has an impact on the screen-positive rate (SPR) in cell-free DNA (cfDNA) screening for trisomy 21. METHODS: Retrospective analysis based on samples analyzed using the Harmony® Prenatal Test (Roche Inc). Due to the size of the data set, we focused on the SPR, which was stratified according to the maternal age, weight, gestational age, and FF distribution. RESULTS: The study cohort consisted of 364,881 patients, including 2614 with a high-risk-result. Median maternal and gestational ages were 34.6 years and 12.4 weeks. FF was dependent on maternal age, weight, and gestational age. SPR was 0.72% and it was independent of maternal weight but was dependent on maternal age. There was a positive but weak association between the FF and the SPR until the FF reached 20.0% (OR p = 1.021, p < 0.001, Nagelkerkes r2 = 0.001). This group included 357,800 pregnancies or 98.1% of the study population. In the group of pregnancies with a FF > 20%, the association was stronger (OR 1.099, p < 0.001, Nagelkerkes r2 = 0.042). CONCLUSION: The SPR in cfDNA screening for trisomy 21 was relatively constant up to a FF of about 20%.

Prediction of Neonatal Growth Restriction in Fetuses With Gastroschisis by Early Third Trimester Ultrasonography Utilizing Contemporary Birth Weight Percentiles.

OBJECTIVE: To identify the estimated fetal weight (EFW) formula and threshold for the optimal prediction of fetal growth restriction (FGR) at 26-34 weeks' in fetuses with gastroschisis. METHODS: Late second and third trimester ultrasound data were used to calculate the EFW utilizing eight different formulas: Hadlock I-IV, Honarvar, Shepard, Siemer, and Warsof. EFW and birth weight percentiles were assigned from US population growth curves. FGR and small for gestational age (SGA) were defined as EFW and birth weight less than the tenth percentile for gestational age; Receiver operating characteristic (ROC) curves were used to compare formula performance for FGR diagnosis at 26-34 weeks' to identify an SGA birth weight. RESULTS: There were 170 newborns with gastroschisis; 46 (27%) were SGA. The mean gestational age at the time of ultrasound was 30.8 ± 1.7 weeks. The mean gestational age at birth was 36.3 ± 1.7 weeks. ROC curve analysis found the Hadlock III formula had the largest area under the curve (AUC) of 0.813 closely followed by Hadlock IV (AUC = 0.811) and Hadlock II (AUC = 0.808) for diagnosis of FGR correlating to neonatal SGA diagnosis. Hadlock II, Hadlock III, and Hadlock IV had the highest diagnostic accuracies when compared to the other EFW formulas. CONCLUSIONS: The Hadlock II, Hadlock III, and Hadlock IV formulas have comparable predictive performance in the optimal identification of FGR in fetuses with gastroschisis at 26-34 weeks'. A threshold of an EFW less than the 25.2th percentile is suggested.

Importance of a detailed anomaly scan after a cfDNA test indicating fetal trisomy 21, 18 or 13.

OBJECTIVE: To investigate the effect of the presence or absence of fetal anomalies and soft markers diagnosed by ultrasound on positive predictive value (PPV) 21, 18 and 13 in pregnancies with a high-risk cfDNA result. METHODS: Retrospective study including singleton pregnancies with high-risk NIPT results for common trisomies followed by invasive testing. The cases were grouped by gestational age at the time of invasive testing and by the presence or absence of fetal abnormalities or soft markers. The ultrasound was considered abnormal if at least one major defect or a soft marker was detected. RESULTS: A total of 173 women were included. Median maternal and gestational age was 37.7 years and 14.0 weeks, respectively. CfDNA test result showed high-risk for trisomy 21 and trisomy 18 or 13 in 119 and 54 cases, respectively. The "pre-ultrasound" PPV for trisomy 21 and for trisomy 18 or 13 were 98.3% and 68.4%, respectively. In case of a high-risk result for trisomy 21 and no fetal anomalies, the PPV was 86.7% while it was 100% if there were anomalies or markers present. In the case of a high-risk result for trisomy 18 or 13, the PPV was 9.5% if the ultrasound examination was normal and 100% if the ultrasound examination was abnormal. CONCLUSION: This study suggests that a detailed ultrasound examination performed after a cfDNA result that is high-risk for one of the common autosomal trisomies adds significantly to establishing an individualized risk assessment. This is particularly true in cases with a high-risk result for trisomies 18 or 13.

Antenatal screening for chromosomal abnormalities.

Screening for chromosomal disorders, especially for trisomy 21, has undergone a number of changes in the last 50 years. Today, cell-free DNA analysis (cfDNA) is the gold standard in screening for trisomy 21. Despite the advantages that cfDNA offers in screening for common trisomies, it must be recognized that it does not address many other chromosomal disorders and any of the structural fetal anomalies. In the first trimester, the optimal approach is to combine an ultrasound assessment of the fetus, which includes an NT measurement, with cfDNA testing. If fetal structural defects are detected or if the NT thickness is increased, an amniocentesis or a CVS with at least chromosomal microarray should be offered.

Identification of fetal aneuploidy with dual-probe fluorescence in situ hybridization analysis in circulating trophoblasts after enrichment using a high-sensitivity microfluidic platform.

OBJECTIVE: To evaluate a microfluidics-based positive selection technology for isolating circulating trophoblasts (CTs) from peripheral blood of women whose pregnancies are affected by aneuploidy and to evaluate fetal karyotype using fluorescence in situ hybridization (FISH). METHOD: Ten 18-ml samples of peripheral blood were collected consecutively from pregnant women whose fetus was affected by aneuploidy. A preservation buffer was added, and the specimens were shipped overnight to the testing laboratory at ambient temperature. The specimen was infused into the fully automated microfluidics-based LiquidScan® instrument without pre-processing. This instrument contains microfluidic chips, which are coated with antibodies (anti-huEpCAM and a proprietary antibody mixture) specific to CT surface epitopes. FISH analysis was performed on the enriched cells. RESULTS: Fetal aneuploidy evaluated included trisomy 21 (n = 3), trisomy 18 (n = 1), trisomy 13 (n = 1), monosomy X (n = 3), and triploidy (n = 1). CTs for analysis by FISH were identified in all samples. The average number of mononucleate cells per 1 ml of whole blood was 2.11 (range 0.38-4.63) overall and was 2.67 (range 1.13-4.63) using the proprietary combination of antibodies. FISH results were concordant with the aneuploidy based on other testing in all cases. Multinucleate cells were searched for and identified in the last seven samples (average number: 0.84/1 ml). CONCLUSIONS: Our study demonstrates that the LiquidScan® , a high-sensitivity microfluidic platform, can enrich circulating trophoblasts (mononucleate and multinucleate). FISH can then be used to detect fetal aneuploidy.

Fetal profile in fetuses with open spina bifida.

OBJECTIVE: To determine whether the frontomaxillary facial (FMF) angle and the prefrontal space ratio (PFSR) are helpful in screening for open spinal defects by ultrasound in the second and third trimesters of pregnancy. METHODS: The FMF angle and the PFSR were measured in fetuses with spina bifida according to standardized protocols. The normal range of the PFSR was previously published by our group. To determine the normal values for the FMF angle in the second and third trimesters of pregnancy, we used the same stored images from the above-mentioned study. RESULTS: 71 affected and 279 normal fetuses were included in this study. Median gestational ages in the two groups were 21.1 weeks and 21.6 weeks, respectively. In fetuses with spina bifida, the FMF angle was significantly smaller than in the normal population (72.9° versus 79.6°). However, the measurement was below the fifth centile in only 22.5% of the affected fetuses. The PFSR was similar in both groups. CONCLUSIONS: The FMF angle is smaller in second and third trimester fetuses with open spina bifida. However, the difference is not large enough to implement this marker in current screening programs.

First trimester uterine artery pulsatility index levels in euploid and aneuploid pregnancies.

OBJECTIVE: To examine whether the uterine artery PI is different in aneuploid and euploid pregnancies. METHODS: Retrospective case-matched study at the department of prenatal medicine at the University of Tuebingen, Germany. The study involved patients with complete data on first trimester screening for trisomies and preeclampsia except PlGF. For each case with trisomy 21 we randomly selected 50 cases with a euploid fetus where complete data on screening for aneuploidy and preeclampsia were also available. The uterine artery pulsatility index and the corresponding MoM values of euploid and the aneuploid population were compared with a Man-Whitney U test. RESULTS: The dataset consisted of 4591 singleton pregnancies. The karyotype was normal in 4500 cases and was abnormal in the remaining 91 pregnancies. There were 50 pregnancies with trisomy 21, 31 with trisomy 18 and 13, and 10 with triploidy. In the group with euploid fetuses, median uterine artery PI was 1.55 (0.99 MoM). In the group with trisomy 21, the median PI (1.42) and MoM (0.89) levels were both significantly lower than in the euploid (p < 0.001). However, the measurements in the trisomy 18 and 13 [1.61 (0.93 MoM)] and in the triploidy [1.99 (1.13 MoM)] groups were not significantly different from those in the euploid group (p = 0.468 and p = 0.632, respectively). CONCLUSION: In conclusion, uterine artery PI levels in the first trimester are slightly lower in pregnancies with trisomy 21. This knowledge may prove to be useful in cases where a low PAPP-A level is seen on the first trimester maternal serum biochemical evaluation to differentiate whether the more likely cause for this finding is placental dysfunction or aneuploidy, specifically trisomy 21.

Splenic artery blood flow as a potential marker for materno-fetal transmission of a primary CMV infection.

OBJECTIVE: To examine the blood flow in the splenic artery as marker for materno-fetal transmission at about 20 weeks following a maternal first-trimester primary CMV infection. METHODS: This is a retrospective study at the prenatal medicine unit at University of Tuebingen, Germany. Women were included who underwent an amniocentesis to examine the fetal infection status following a maternal primary CMV infection in the first trimester. In all cases, amniocentesis was done at about 20 weeks and at least 6 weeks after the maternal infection. As part of the detailed ultrasound examination prior to each amniocentesis, we examined the peak systolic velocity flow (PSV) and the pulsatility index (PI) of the splenic artery. Measurements were transformed into MoMs according to the normal curves of Ebbing et al. RESULTS: 81 Women fulfilled the inclusion criteria. Maternal and gestational age was 31.9 years and 20.6 weeks' gestation. Maternal-fetal transmission occurred in 13 of the cases. In fetuses without and with a CMV infection, mean PI was 0.98 MoM and 0.89 (p = 0.081). Mean PSV was significantly higher in the group of infected fetuses than in those without (1.24 vs. 0.94 MoM, p = 0.026). CONCLUSION: The PSV may be a marker for maternal-fetal CMV transmission following a first-trimester maternal infection.

False-positive rates in screening for trisomies 18 and 13: a comparison between first-trimester combined screening and a cfDNA-based approach.

PURPOSE: To determine the false-positive rates (FPR) associated with screening for trisomy 18/13 using first-trimester combined screening (FTCS) and an ultrasound plus cfDNA-based approach (US-cfDNA), which includes a detailed ultrasound examination, a cfDNA analysis and a FTCS reflex backup test for cases with uninformative results. METHODS: This is a sub-analysis of a randomized controlled trial, which was performed between 2015 and 2016. Pregnant women with a normal first-trimester ultrasound examination at 11-13 weeks' gestation (NT < 3.5 mm, no anomalies) were randomized into two groups: FTCS and US-cfDNA screening. The overall FPR in screening for trisomies 18/13 and 21 was compared with the FPR in screening for trisomy 21 alone. Pregnancies were considered screen positive if the risk for trisomy 21 was 1:100 and for trisomy 18 and 13, 1:20 each. RESULTS: The study population consisted of 688 pregnancies in each study arm. In the FCTS group, median delta NT was 0.0 mm, free beta-hCG and PAPP-A 0.96 and 1.11 MoM. In the US-cfDNA group, median delta NT was 0.0 mm. In 10 pregnancies, the cfDNA analysis was uninformative. In the FTCS and in the US-cfDNA group, the FPR in screening for trisomy 21 was 2.5% and 0%. In both groups, the overall FPR was not increased by adding screening algorithms for trisomies 18 and 13. CONCLUSION: In conclusion, the addition of screening for trisomies 18 and 13 to screening for trisomy 21 does not significantly change FPR. This is true for both the FTCS and the US-cfDNA-based approach.

False-Positive Rate in First-Trimester Screening Based on Ultrasound and Cell-Free DNA versus First-Trimester Combined Screening with Additional Ultrasound Markers.

OBJECTIVE: To determine whether screening for trisomy 21 based on first-trimester combined screening (FTCS) with assessment of nasal bone (NB), tricuspid flow (TCF), and ductus venosus flow (DVF) results in similar false-positive rates compared to ultrasound and cell-free DNA (cfDNA) screening. METHODS: This is a subanalysis of a prospective randomized controlled trial which was performed between October 2015 and December 2016. Pregnant women with a normal first-trimester ultrasound examination at 11 to 13 weeks' gestation were randomized into two groups: (1) FTCS with assessment of the NB, TCF, and DVF (extended FTCS [eFTCS]), and (2) ultrasound + cfDNA screening. The false-positive rate in screening for trisomy 21 was defined as the primary outcome parameter. RESULTS: The study population consisted of 688 women in each study arm. In the eFTCS group, the median delta fetal nuchal translucency thickness (NT) was 0.0 mm, free beta-hCG and PAPP-A were 0.96 and 1.11 MoM, and NB, TCF, and DVF PIV were abnormal in 0.9, 0.6, and 7.0% cases. In the ultrasound + cfDNA group, the median delta NT was 0.0 mm. In 10 pregnancies the cfDNA analysis was uninformative and the risk of trisomy 21 was based on eFTCS. There were no false-positive cases in the ultrasound + cfDNA group, whereas the false-positive rates were between 0.9 and 2.2% with eFTCS. CONCLUSION: Screening for trisomy 21 based on ultrasound + cfDNA has a lower false-positive rate than screening based on eFTCS.

First-trimester screening for early and late preeclampsia using maternal characteristics, biomarkers, and estimated placental volume.

BACKGROUND: Preeclampsia is a major cause of perinatal morbidity and mortality. First-trimester screening has been shown to be effective in selecting patients at an increased risk for preeclampsia in some studies. OBJECTIVE: We sought to evaluate the feasibility of screening for preeclampsia in the first trimester based on maternal characteristics, medical history, biomarkers, and placental volume. STUDY DESIGN: This is a prospective observational nonintervention cohort study in an unselected US population. Patients who presented for an ultrasound examination between 11-13+6 weeks' gestation were included. The following parameters were assessed and were used to calculate the risk of preeclampsia: maternal characteristics (demographic, anthropometric, and medical history), maternal biomarkers (mean arterial pressure, uterine artery pulsatility index, placental growth factor, pregnancy-associated plasma protein A, and maternal serum alpha-fetoprotein), and estimated placental volume. After delivery, medical records were searched for the diagnosis of preeclampsia. Detection rates for early-onset preeclampsia (<34 weeks' gestation) and later-onset preeclampsia (≥34 weeks' gestation) for 5% and 10% false-positive rates using various combinations of markers were calculated. RESULTS: We screened 1288 patients of whom 1068 (82.99%) were available for analysis. In all, 46 (4.3%) developed preeclampsia, with 13 (1.22%) having early-onset preeclampsia and 33 (3.09%) having late-onset preeclampsia. Using maternal characteristics, serum biomarkers, and uterine artery pulsatility index, the detection rate of early-onset preeclampsia for either 5% or 10% false-positive rate was 85%. With the same protocol, the detection rates for preeclampsia with delivery <37 weeks were 52% and 60% for 5% and 10% false-positive rates, respectively. Based on maternal characteristics, the detection rates for late-onset preeclampsia were 15% and 48% for 5% and 10%, while for preeclampsia at ≥37 weeks' gestation the detection rates were 24% and 43%, respectively. The detection rates for late-onset preeclampsia and preeclampsia with delivery at >37 weeks' gestation were not improved by the addition of biomarkers. CONCLUSION: Screening for preeclampsia at 11-13+6 weeks' gestation using maternal characteristics and biomarkers is associated with a high detection rate for a low false-positive rate. Screening for late-onset preeclampsia yields a much poorer performance. In this study the utility of estimated placental volume and mean arterial pressure was limited but larger studies are needed to ultimately determine the effectiveness of these markers.

Antenatal treatment options for primary cytomegalovirus infections.

PURPOSE OF REVIEW: Cytomegalovirus (CMV) infection is by far the most common fetal viral infection. It carries a risk of long-term sequelae for the neonate; though the severity depends on the gestational age at the time of infection. Improvement in primary prevention of a CMV infection during pregnancy can be achieved by providing information regarding hygiene to the mother. Once a maternal infection occurs, treatment options include prevention of maternal-fetal transmission and, once transmission occurs, attempts to reduce the severity of its effect on the fetus. RECENT FINDINGS: Several recent studies have shown that providing detailed information regarding the effects of CMV on the fetus and providing common sense hygiene advice reduced new primary infections by more than 75%. In cases with a documented maternal primary CMV infection, treatment with intravenous immunoglobulins have been tried to reduce maternal fetal transmission with a variable degree of success. In the randomized controlled study of Revello et al., immunoglobulins did not reduce the transmission rate. In a recent study, immunoglobulins were given only to women with very recent first trimester infections. In this study, the transmission rate was 2.5%, which is significantly less than expected. Leruez-Ville et al. treated mothers with known transmission of CMV to the fetus with 8 g of valaciclovir daily. They observed a significant reduction in the number of neonatal symptoms in the treated cases. SUMMARY: Protocols are available to prevent primary CMV infections during pregnancy and, in cases where an infection does occur, steps can be taken to reduce its effect on the fetus thereby reducing the chance of long-term sequelae.

First trimester screening for major cardiac defects based on the ductus venosus flow in fetuses with trisomy 21.

OBJECTIVE: To examine whether in fetuses with trisomy 21 (T21), the ductus venosus (DV) flow differs in presence of a major cardiac defect (congenital cardiac defect [CHD]) and whether this affects the risk distribution in first trimester screening for T21. METHODS: This retrospective study included pregnant women who underwent first trimester screening. This involves an examination of the crown-rump length, the nuchal translucency, the ductus venosus (DV) flow, and the heart. Three groups of fetuses were examined: euploid without CHD, T21 with CHD, and T21 without CHD. We examined the DV pulsatility index for veins, the direction of the a-wave, and ratios of velocities: v/S, v/D, a/S, a/D, and S/D. RESULTS: The study population consisted of 410 euploid fetuses and 136 with T21 (51 with CHD and 85 without CHD). In the 3 groups, the a-wave was reversed in 3.2%, 66.7%, and 57.6%. The DV flow ratios in T21 with and without CDH were significantly different compared with normal fetuses. When comparing the ratios between the 2 T21 groups, only the a/S and a/D ratio were significantly different. The risk distributions in screening for T21 with and without CDH were similar. CONCLUSION: There are some small differences in the DV flow of T21 fetuses with and without CHD, but they are not clinically useful.

First-trimester ultrasound screening for trisomy 21 based on maternal age, fetal nuchal translucency, and different methods of ductus venosus assessment.

OBJECTIVE: To examine whether combining the dichotomous assessment of the a-wave and the ductus venosus (DV) pulsatility index for veins (PIV) measurement improves first-trimester screening performance. METHODS: Retrospective study performed at the University Hospital of Tuebingen based on singleton pregnancies that underwent first-trimester screening including DV flow assessment. In each case, the risk of trisomy 21 was calculated based on maternal age, fetal nuchal translucency, and DV flow either as dichotomous classification of the a-wave, as measurement of the DV PIV, or both. RESULTS: There were 5280 euploid fetuses and 127 fetuses with trisomy 21. The DV a-wave was reversed in 2.3% and 66.1% in the euploid and trisomy 21 cases, respectively. The DV PIV measurements were above the 95th percentile in 8.3% and 77.2% the euploid and trisomy 21 cases, respectively. For a false positive rate of 3%, the detection rate for trisomy 21 based on maternal age, fetal NT, and DV flow is about 87% irrespective of whether DV is examined as a continuous or dichotomous variable. The combination of both resulted in a small decrease at 3% false positive rate. CONCLUSION: Assessment of the DV a-wave and the DV PIV result in similar DRs. Combining these two approaches does not appear to improve their individual screening performance. © 2017 John Wiley & Sons, Ltd.

Combined screening test for trisomy 21 - is it as efficient as we believe?

OBJECTIVES: To compare two first-trimester screening strategies: traditional combined screening and the one based on ultrasound markers only. We investigated the effect of maternal age (MA) on the screening performance of both of these strategies. METHODS: This was a prospective observational study based on a non-selected mixed-risk population of 11,653 women referred for first-trimester screening. The study population was divided in two groups: combined screening (CS) and ultrasound-based screening (US). Absolute risk was calculated to determine the influence of MA on screening performance. RESULTS: The CS arm comprised 5145 subjects including 51 cases of trisomy 21 (T21), and the US arm comprised 5733 subjects including 87 subjects with T21. Seven hundred and seventy-five subjects were excluded from the study. For a false positive rate (FPR) of 3%, the detection rate (DR) of T21 in CS arm was 78% vs. 90% in US arm. For 5% FPR, DR was 84% and 94% in CS and US arm, respectively. MA had an influence on DR positive rates in CS: both DR and FPR for T21 increased with advance in MA. CONCLUSIONS: The US protocol showed higher DR of T21 compared to the CS one. It may be considered as a viable alternative to CS for T21 where access to biochemical testing is limited.

Principles of first trimester screening in the age of non-invasive prenatal diagnosis: screening for other major defects and pregnancy complications.

PURPOSE: First trimester risk assessment plays a major role in the contemporary pregnancy care. It has evolved significantly since its introduction in the 1990s when it essentially consisted of just the nuchal translucency measurement. Today, it involves the measurement of several biophysical and biochemical markers and can assess the risk for a wide array of major chromosomal and non-chromosomal defects as well as other pregnancy-related complications. METHODS: A search of the Medline and Embase databases was done looking for articles about first trimester screening. We performed a detailed review of the literature to evaluate the screening tests currently available and their respective test performance. RESULTS: The detailed ultrasound examination results in the detection of about half of major structural defects, determination of a very accurate gestational age, and identification of multiple pregnancies as well as their chorionicity. In addition, risk assessment for preeclampsia and early IUGR can be established at this stage. In case of an increased risk, the daily use of low-dose aspirin can be offered at a point in pregnancy when it still can have a positive impact. Additional screening tests for gestational diabetes and macrosomia are available. CONCLUSION: Contemporary first trimester screening is essential to establish an individual risk profile and can be used to tailor the pregnancy care.

Principles of first trimester screening in the age of non-invasive prenatal diagnosis: screening for chromosomal abnormalities.

PURPOSE: First trimester risk assessment for chromosomal abnormalities plays a major role in the contemporary pregnancy care. It has evolved significantly since its introduction in the 1990s, when it essentially consisted of just the nuchal translucency measurement. Today, it involves the measurement of several biophysical and biochemical markers and it is often combined with a cell-free DNA (cfDNA) analysis as a secondary test. METHODS: A search of the Medline and Embase databases was done looking for articles about first trimester aneuploidy screening. We performed a detailed review of the literature to evaluate the screening tests currently available and their respective test performance. RESULTS: Combined screening for trisomy 21 based on maternal age, fetal NT, and the serum markers free beta-hCG and PAPP-A results in a detection rate of about 90% for a false positive of 3-5%. With the addition of further ultrasound markers, the false positive rate can be roughly halved. Screening based on cfDNA identifies about 99% of the affected fetuses for a false positive rate of 0.1%. However, there is a test failure rate of about 2%. The ideal combination between combined and cfDNA screening is still under discussion. Currently, a contingent screening policy seems most favorable where combined screening is offered for everyone and cfDNA analysis only for those with a borderline risk result after combined screening. CONCLUSION: Significant advances in screening for trisomy 21 have been made over the past 2 decades. Contemporary screening policies can detect for more than 95% of affected fetuses for false positive rate of less than 3%.