How does cell-based non-invasive prenatal test (NIPT) perform against chorionic villus sampling and cell-free NIPT in detecting trisomies and copy number variations? A clinical study from Denmark.

OBJECTIVES: We aimed to compare cell-based NIPT (cbNIPT) to chorionic villus sampling (CVS) and to examine the test characteristics of cbNIPT in the first clinical validation study of cbNIPT compared to cell-free NIPT (cfNIPT). MATERIAL AND METHODS: Study 1: Women (N = 92) who accepted CVS were recruited for cbNIPT (53 normal and 39 abnormal). Samples were analyzed with chromosomal microarray (CMA). Study 2: Women (N = 282) who accepted cfNIPT were recruited for cbNIPT. cfNIPT was analyzed using sequencing and cbNIPT by CMA. RESULTS: Study 1: cbNIPT detected all aberrations (32/32) found in CVS: trisomies 13, 18 and 21 (23/23), pathogenic copy number variations (CNVs) (6/6) and sex chromosome aberrations (3/3). cbNIPT detected 3/8 cases of mosaicism in the placenta. Study 2: cbNIPT detected all trisomies found with cfNIPT (6/6) and had no false positive (0/246). One of the three CNVs called by cbNIPT was confirmed by CVS but was undetected by cfNIPT, two were false positives. cbNIPT detected mosaicism in five samples, of which two were not detected by cfNIPT. cbNIPT failed in 7.8% compared to 2.8% in cfNIPT. CONCLUSION: Circulating trophoblasts in the maternal circulation provide the potential of screening for aneuploidies and pathogenic CNVs covering the entire fetal genome.

Consortium for the Study of Pregnancy Treatments (Co-OPT): An international birth cohort to study the effects of antenatal corticosteroids.

BACKGROUND: Antenatal corticosteroids (ACS) are widely prescribed to improve outcomes following preterm birth. Significant knowledge gaps surround their safety, long-term effects, optimal timing and dosage. Almost half of women given ACS give birth outside the "therapeutic window" and have not delivered over 7 days later. Overtreatment with ACS is a concern, as evidence accumulates of risks of unnecessary ACS exposure. METHODS: The Consortium for the Study of Pregnancy Treatments (Co-OPT) was established to address research questions surrounding safety of medications in pregnancy. We created an international birth cohort containing information on ACS exposure and pregnancy and neonatal outcomes by combining data from four national/provincial birth registers and one hospital database, and follow-up through linked population-level data from death registers and electronic health records. RESULTS AND DISCUSSION: The Co-OPT ACS cohort contains 2.28 million pregnancies and babies, born in Finland, Iceland, Israel, Canada and Scotland, between 1990 and 2019. Births from 22 to 45 weeks' gestation were included; 92.9% were at term (≥ 37 completed weeks). 3.6% of babies were exposed to ACS (67.0% and 77.9% of singleton and multiple births before 34 weeks, respectively). Rates of ACS exposure increased across the study period. Of all ACS-exposed babies, 26.8% were born at term. Longitudinal childhood data were available for 1.64 million live births. Follow-up includes diagnoses of a range of physical and mental disorders from the Finnish Hospital Register, diagnoses of mental, behavioural, and neurodevelopmental disorders from the Icelandic Patient Registers, and preschool reviews from the Scottish Child Health Surveillance Programme. The Co-OPT ACS cohort is the largest international birth cohort to date with data on ACS exposure and maternal, perinatal and childhood outcomes. Its large scale will enable assessment of important rare outcomes such as perinatal mortality, and comprehensive evaluation of the short- and long-term safety and efficacy of ACS.

Measuring leading placental edge to internal cervical os: Transabdominal versus transvaginal approach.

We aimed to compare the value of transabdominal (TA) and transvaginal (TV) approaches for assessing the risk of a low-lying placenta. This involved a comparison of TA and TV measurements between the leading placental edge and the internal cervical os. We also assessed the intra-/interobserver variation for these measurements and the efficacy of TA measures in screening for a low placenta. METHODOLOGY: Transabdominal and TV measurements of the leading placental edge to the internal cervical os were performed on 369 consecutive pregnancies of 16-41 weeks' gestation. The difference (TA-TV) from the mean was calculated and plotted against gestational age. Bland-Altman plots and paired t-tests were used to look at the differences in TA/TV measurement. Screening performance of a transabdominal approach was compared to a transvaginal 'gold standard'. Nonparametric methods were used to calculate the area under the receiver operator characteristics (ROC) curve. Intra-/interobserver variations were also calculated. RESULTS: Of the pregnancies, 278 had a leading placental edge that was visible with the TV approach. Differences (TA-TV) ranged from -50 mm to +57 mm. Bland-Altman plot shows that TA measurements overestimated the distance compared with the TV measurements; the average difference in measurement was 12.0 mm (95% confidence interval 9.9-14.1). The sensitivity, specificity and negative predictive values of a TA approach were 18.2%, 97.5% and 87.2%, respectively. The receiver operator characteristics area between gestational weeks 16-23 was 0.81 (95% CI: 0.76-0.86). CONCLUSION: The TA approach has a low sensitivity for detecting a low-lying placenta as choosing a TA cut-off with sensitivity >90% will decrease the specificity to 50%.