CX3CL1/Fractalkine as a biomarker for early pregnancy prediction of preterm premature rupture of membranes.

OBJECTIVES: The objective of our study was to evaluate serum CX3CL1/Fractalkine, a monocyte/macrophage chemoattractant expressed in cytotrophoblasts and decidual cells, as a predictive biomarker for the occurrence of preterm premature rupture of membranes (PPROM). METHODS: A case-control study of 438 pregnancies including 82 PPROM cases and 64 preterm labor with intact membranes cases with blood samples collected at first trimester, second trimester and delivery was conducted. The predictive ability of CX3CL1 and maternal risk factors for the occurrence of PPROM was assessed by receiver operating characteristic curve analysis. A second, independent cohort was prospectively constituted to confirm the case-control study results. RESULTS: First trimester CX3CL1 was significantly increased in PPROM cases when compared to matched controls. Multivariate regression analysis highlighted a significant difference for CX3CL1 measured during the first trimester (p<0.001). Alone, CX3CL1 predicts PPROM with a 90 % sensitivity and a specificity around 40 %. The area under the receiver operating characteristic curve for PPROM prediction were 0.64 (95% confidence interval: 0.57-0.71) for first trimester CX3CL1, and 0.61 (95% confidence interval: 0.54-0.68) for maternal risk factors (body mass index<18.5 kg/m2, nulliparity, tobacco use and the absence of high school diploma). The combination of CX3CL1 and maternal risk factors significantly improved the area under the curve: 0.72 (95% confidence interval: 0.66-0.79) (p<0.001). The results were confirmed on a second independent cohort. CONCLUSIONS: CX3CL1 is a promising blood biomarker in the early (first trimester) prediction of PPROM.

Methods and Software to Analyze Gene-Environment Interactions under a Case-Mother-Control-Mother Design with Partially Missing Child Genotype.

INTRODUCTION: The case-mother-control-mother design allows to study fetal and maternal genetic factors together with environmental exposures on early life outcomes. Mendelian constraints and conditional independence between child genotype and environmental factors enabled semiparametric likelihood methods to estimate logistic models with greater efficiency than standard logistic regression. Difficulties in child genotype collection require methods handling missing child genotype. METHODS: We review a stratified retrospective likelihood and two semiparametric likelihood approaches: a prospective one and a modified retrospective one, the latter either modeling the maternal genotype as a function of covariates or leaving their joint distribution unspecified (robust version). We also review software implementing these modeling alternatives, compare their statistical properties in a simulation study, and illustrate their application, focusing on gene-environment interactions and partially missing child genotype. RESULTS: The robust retrospective likelihood provides generally unbiased estimates, with standard errors only slightly larger than when modeling maternal genotype based on exposure. The prospective likelihood encounters maximization problems. In the application to the association of small-for-gestational-age babies with CYP2E1 and drinking water disinfection by-products, the retrospective likelihood allowed a full array of covariates, while the prospective likelihood was limited to few covariates. CONCLUSION: We recommend the robust version of the modified retrospective likelihood.

First-trimester screening for Down syndrome using quadruple maternal biochemical markers.

OBJECTIVES: Placental growth factor (PlGF) is used for first-trimester preeclampsia screening and could be combined with other biochemical markers for Down syndrome screening. We aim to estimate the predictive value of the combination of pregnancy-associated plasma protein (PAPP-A), free ß-human chorionic gonadotropin (free ß-hCG), placental growth factor (PlGF) and α-fetoprotein (AFP) with and without nuchal translucency. METHODS: Singleton pregnancies recruited at 11-14 weeks and followed until delivery. The four maternal markers were measured using Kryptor (ThermoFisher-BRAHMS) and adjusted for gestational age and maternal characteristics. The risk of Down syndrome was calculated using the Fetal Medicine Foundation algorithm and multivariate linear regression analyses in all cases and in 2,200 controls. Receiver-operator characteristic (ROC) curves were used to calculate the detection and false-positive rates. RESULTS: Twenty-six (0.2%) cases of Down syndrome were diagnosed among 13,386 participants. The combination of the four biomarkers could have detected 88% (95% CI: 72-97%) of the cases at a false-positive rate of 13% (95% CI: 12-15%). The addition of nuchal translucency would have increased the detection rate to 96% (95% CI: 82-99%) at a false-positive rate of 4% (95% CI: 4-5%) using a 1:300 cut-off and to 100% (95% CI: 89-100%) at a false-positive rate of 6% (95% CI: 5-8%) using a 1:500 cut-off. CONCLUSIONS: First-trimester screening using biochemical markers allows the identification of approximately 88% of Down syndrome cases for a false-positive rate of 13%. The addition of nuchal translucency raises the detection rate above 95% with a false-positive rate below 5%.

Impact of COVID-19 and Vaccination During Pregnancy on Placenta-Mediated Complications (COVIGRO Study).

OBJECTIVES: COVID-19 has been associated with preterm birth (PTB) and placental-mediated complications, including fetal growth restriction and preeclampsia (PE). This study aimed to estimate the impact of COVID-19 and vaccination on adverse pregnancy outcomes and markers of placental function. METHODS: We performed a study on a prospective cohort of women recruited in the first trimester of pregnancy during the early COVID-19 pandemic period (December 2020 to December 2021). At each trimester of pregnancy, the assessment included a questionnaire on COVID-19 and vaccination status; serological tests for COVID-19 (for asymptomatic infection); measurement of placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt-1) in maternal blood; measurement of mean uterine artery pulsatility index (UtA-PI); and pregnancy outcomes (PTB, PE, birth weight below the fifth and the tenth percentile). RESULTS: Among 788 patients with complete data, we observed 101 (13%) cases of symptomatic infection and 74 (9%) cases of asymptomatic infection with SARS-CoV-2. Most cases (73%) of infection were among women with previous vaccination or COVID-19 infection before pregnancy. COVID-19 infection was not associated with adverse pregnancy outcomes, abnormal fetal growth, sFlt-1/PlGF ratio, or mean UtA-PI. Vaccination during pregnancy did not influence these outcomes either. We observed no case of severe COVID-19 infection requiring respiratory support. CONCLUSION: Mild symptomatic or asymptomatic COVID-19 during pregnancy did not influence the risk of adverse pregnancy outcomes and the markers of placental function in predominantly vaccinated women. Fetal growth monitoring is unlikely to be mandatory in women with mild symptoms of COVID-19.

Cumulative exposure to psychosocial stressors at work and global cognitive function: the PROspective Quebec Study on Work and Health.

OBJECTIVES: Psychosocial stressors at work have been proposed as modifiable risk factors for mild cognitive impairment (MCI). This study aimed to evaluate the effect of cumulative exposure to psychosocial stressors at work on cognitive function. METHODS: This study was conducted among 9188 white-collar workers recruited in 1991-1993 (T1), with follow-ups 8 (T2) and 24 years later (T3). After excluding death, losses to follow-up and retirees at T2, 5728 participants were included. Psychosocial stressors at work were measured according to the Karasek's questionnaire. Global cognitive function was measured with the Montreal Cognitive Assessment. Cumulative exposures to low psychological demand, low job control, passive job and high strain job were evaluated using marginal structural models including multiple imputation and inverse probability of censoring weighting. RESULTS: In men, cumulative exposures (T1 and T2) to low psychological demand, low job control or passive job were associated with higher prevalences of more severe presentation of MCI (MSMCI) at T3 (Prevalence ratios (PRs) and 95% CIs of 1.50 (1.16 to 1.94); 1.38 (1.07 to 1.79) and 1.55 (1.20 to 2.00), respectively), but not with milder presentation of MCI. In women, only exposure to low psychological demand or passive job at T2 was associated with higher prevalences of MSMCI at T3 (PRs and 95% CI of 1.39 (0.97 to 1.99) and 1.29 (0.94 to 1.76), respectively). CONCLUSIONS: These results support the deleterious effect of a low stimulating job on cognitive function and the cognitive reserve theory. Psychosocial stressors at work could be part of the effort for the primary prevention of cognitive decline.

First-Trimester Preterm Preeclampsia Screening in Nulliparous Women: The Great Obstetrical Syndrome (GOS) Study.

OBJECTIVES: To estimate the ability of a combination of first-trimester markers to predict preterm preeclampsia in nulliparous women. METHODS: We conducted a prospective cohort study of nulliparous women with singleton gestations, recruited between 110 and 136 weeks gestation. Data on the following were collected: maternal age; ethnicity; chronic diseases; use of fertility treatment; body mass index; mean arterial blood pressure (MAP); serum levels of pregnancy-associated plasma protein A (PAPP-A), placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), alpha fetoprotein (AFP), free beta human chorionic gonadotropin (ß-hCG); and mean uterine artery pulsatility index (UtA-PI). We constructed a proportional hazard model for the prediction of preterm preeclampsia selected based on the Akaike information criterion. A receiver operating characteristic curve was created with the predicted risk from the final model. Our primary outcome was preterm preeclampsia and our secondary outcome was a composite of preeclampsia, small for gestational age, intrauterine death, and preterm birth. RESULTS: Among 4659 nulliparous women with singleton gestations, our final model included 4 variables: MAP MoM, log10PlGF MoM, log10AFP MoM and log10UtA-PI MoM. We obtained an area under the curve of 0.84 (95% CI 0.75-0.93) with a detection rate of preterm preeclampsia of 55% (95% CI 37%-73%) and a false-positive rate of 10%. Using a risk cut-off with a false-positive rate of 10%, the positive predictive value for our composite outcome was 33% (95% CI 29%-37%). CONCLUSIONS: The combination of MAP, maternal serum PlGF and AFP, and UtA-PI are useful to identify nulliparous women at high risk of preterm preeclampsia but also at high risk of other great obstetrical syndromes.

Cord blood S100B: reference ranges and interest for early identification of newborns with brain injury.

Background Neurological complications are common in the premature and full-term neonates admitted to the intensive care unit, but the diagnosis of these complications is often difficult to make. S100B protein, measured in cord blood, may represent a valuable tool to better identify patients at risk of brain injury. Methods As a first step, we established S100B cord blood serum reference intervals from 183 preterm and 200 full-term neonates. We then measured cord blood serum S100B to identify neurological complications in 272 neonates hospitalized at the neonatal intensive care unit (NICU). Diagnosis of brain injury relied on imaging examination. Results The 95th percentiles of S100B concentration in cord blood were established as 1.21 µg/L for the 383 neonates, 0.96 µg/L for full-term neonates and 1.36 µg/L for premature neonates. Among the 272 neonates hospitalized at the NICU, 11 presented neurological complications. Using 1.27 µg/L as the optimal sensitivity/specificity threshold, S100B differentiate neonates with and without neurological complications with a sensitivity of 45.5% (95% confidence intervals [CI]: 16.7-76.6) and a specificity of 88.9% (95% CI: 84.4-92.4) (p = 0.006). In combination with arterial pH (<7.25), sensitivity increased to 90.9% (95% CI: 58.7-99.8), while specificity was 51.2% (95% CI: 44.8-57.7). The sensitivity is significantly (p = 0.03) increased in comparison to S100B alone. The specificity is significantly higher with S100B only than with pH + S100B (p < 0.001). Conclusions Cord blood S100B protein, in combination with arterial cord blood pH, has the potential to help clinicians to detect at birth neurological complications in neonates hospitalized in an NCIU.

Measuring the chronology of the translational process of molecular genetic discoveries.

Background The process of technology validation and transfer of new molecular diagnostic tests towards the clinic faces challenges and needs to be improved. There is no empirical measure of the chronology and pace of technology transfer of molecular genetic discoveries. Methods We studied these for 29 molecular genetic test discoveries in order to (1) provide estimates of the timeframe between discovery of a clinical application and complete clinical implementation, and (2) compare the trajectories between different new tests to identify common patterns. We identified 11 publicly available "timestamps" for the technology transfer process ranging from discovery of the marker to use in a clinical setting. For each test selected, we searched public databases to identify available timestamps and dates. We plotted and compared trajectories of individual tests, including chronology. Results We show that there is much variability in the chronology of transfer between biomarkers. The median time between discovery of the marker and availability of the clinical test was 9.5 years (minimum 1). There was a median time of 18 years between test discovery and FDA approval (minimum 7 years), and it took a median of 17 years between discovery and the availability of a certified reference material for the 10 assays that have one (minimum 9 years). Conclusions We conclude that new molecular genetic tests take significant time between discovery and clinical implementation, and that further work is needed to pinpoint key factors, including policy and organization factors, that may allow for improving and streamlining this process.

Use of antidepressants and anxiolytics in early pregnancy and the risk of preeclampsia and gestational hypertension: a prospective study.

BACKGROUND: We investigated the association between antidepressant and anxiolytic exposure during the first and early second trimester of pregnancy (< 16 weeks), and hypertensive disorders of pregnancy (including preeclampsia and gestational hypertension) in women with singleton pregnancy. METHODS: This study is based on a large prospective cohort of 7866 pregnant women. We included pregnant women aged 18 years or older without chronic hepatic or renal disease at the time of recruitment. Participants lost to the follow-up, with multiple pregnancies and pregnancy terminations, miscarriages or fetal deaths before 20 weeks of gestation were excluded from the study, as well as women with no data on the antidepressant/anxiolytic medication use during pregnancy. Information concerning antidepressant or anxiolytic medication use was extracted from hospital records after delivery. The associations between their use and the risk of gestational hypertension or preeclampsia were calculated. RESULTS: The final sample for analysis included 6761 participants including 218 (3.2%) women who were exposed to antidepressant and/or anxiolytic medication before the 16th week of gestation. Forty-one women had a non-medicated depression or anxiety during the pregnancy. Moreover, 195 (2.9%) and 122 (1.8%) women developed gestational hypertension and preeclampsia respectively. When compared to women unexposed to antidepressant/anxiolytic medication, depression and anxiety, those using antidepressant and/or anxiolytic drugs before the 16th week of gestation were at increased risk of preeclampsia (adjusted odd ratio (aOR) 3.09 [CI95% 1.56-6.12]), especially if they continued their medication after the 16th week (aOR 3.41 [CI95% 1.66-7.02]) compared to those who did not (1.60 [CI95% 0.21-12.34]). CONCLUSIONS: Women exposed to antidepressant and/or anxiolytic medication before the 16th week of pregnancy have a 3-fold increased risk for preeclampsia when compared to women unexposed to antidepressant/anxiolytic medication, depression and anxiety. Also, our results suggested that women who stopped their medication before the 16th week of pregnancy could be benefit from reduced preeclampsia risk.

First-Trimester Placental Growth Factor for the Prediction of Preeclampsia in Nulliparous Women: The Great Obstetrical Syndromes Cohort Study.

BACKGROUND: First-trimester maternal serum markers have been associated with preeclampsia (PE). We aimed to evaluate the performance of first-trimester placental growth factor (PlGF) for the prediction of PE in nulliparous women. SUBJECTS AND METHODS: We conducted a prospective cohort study of nulliparous women with singleton pregnancy at 11-13 weeks. Maternal serum PlGF concentration was measured using B·R·A·H·M·S PlGFplus KRYPTOR automated assays and reported in multiple of the median adjusted for gestational age. We used proportional hazard models, along with receiver operating characteristic curves and areas under the curve (AUC). RESULTS: Out of 4,652 participants, we observed 232 (4.9%) cases of PE including 202 (4.3%) term and 30 (0.6%) preterm PE. PlGF was associated with the risk of term (AUC = 0.61, 95% confidence interval [CI] 0.57-0.65) and preterm PE (AUC = 0.73, 95% CI 0.64-0.83). The models were improved with the addition of maternal characteristics (AUC for term PE 0.66, 95% CI 0.62-0.71; AUC for preterm PE 0.81, 95% CI 0.72-0.91; p < 0.01). At a false-positive rate of 10%, PlGF combined with maternal characteristics could have predicted 26% of term and 55% of preterm PE. The addition of pregnancy-associated plasma protein A did not significantly improve the prediction models. CONCLUSION: First-trimester PlGF combined with maternal characteristics is useful to predict preterm PE in nulliparous women.

Hypersuccinylacetonaemia and normal liver function in maleylacetoacetate isomerase deficiency.

BACKGROUND: A high level of succinylacetone (SA) in blood is a sensitive, specific newborn screening marker for hepatorenal tyrosinemia type 1 (HT1, MIM 276700) caused by deficiency of fumarylacetoacetate hydrolase (FAH). Newborns with HT1 are usually clinically asymptomatic but show liver dysfunction with coagulation abnormalities (prolonged prothrombin time and/or high international normalised ratio). Early treatment with nitisinone (NTBC) plus dietary restriction of tyrosine and phenylalanine prevents the complications of severe liver disease and neurological crises. METHODS AND RESULTS: Six newborns referred for hypersuccinylacetonaemia but who had normal coagulation testing on initial evaluation had sequence variants in the GSTZ1 gene, encoding maleylacetoacetate isomerase (MAAI), the enzyme preceding FAH in tyrosine degradation. Initial plasma SA levels ranged from 233 to 1282 nmol/L, greater than normal (<24 nmol/L) but less than the initial values of patients with HT1 (16 944-74 377 nmol/L, n=15). Four individuals were homozygous for c.449C>T (p.Ala150Val). One was compound heterozygous for c.259C>T (p.Arg87Ter) and an intronic sequence variant. In one, a single heterozygous GSTZ1 sequence variant was identified, c.295G>A (p.Val99Met). Bacterial expression of p.Ala150Val and p.Val99Met revealed low MAAI activity. The six individuals with mild hypersuccinylacetonaemia (MHSA) were not treated with diet or nitisinone. Their clinical course has been normal for up to 13 years. CONCLUSIONS: MHSA can be caused by sequence variants in GSTZ1. Such individuals have thus far remained asymptomatic despite receiving no specific treatment.

First Trimester Screening for Fetal Aneuploidies Using Placental Growth Factor: The Great Obstetrical Syndrome (GOS) Study.

OBJECTIVE: This study sought to estimate the ability of first trimester maternal serum placental growth factor (PlGF) to identify fetal aneuploidies. METHODS: A prospective cohort study of singleton pregnancy at 11 to 13 weeks was conducted. Maternal serum PlGF concentration was measured using BRAHMS PlGF plus KRYPTOR automated assays (Thermo Scientific BRAHMS, Hennigsdorf, Germany). PlGF and nuchal translucency were log-transformed and reported as multiples of the median (MoM) adjusted for crown-rump length. Detection rates were calculated using receiver-operator characteristic curves. RESULTS: The study observed 21 cases of fetal aneuploidies (0.4%) out of 4765 participants. Trisomy 21 (13 cases; 0.85 MoM; interquartile range [IQR] 0.80-0.93), trisomy 18 (two cases; 0.77 MoM; IQR 0.66-0.87) and trisomy 13 (two cases; 0.68 MoM; IQR 0.61-0.75) were associated with low PlGF concentrations. The low PlGF values observed in the cases of monosomy X (two cases; 0.85 MoM; IQR 0.82-0.88, P = 0.05), triploidy (0.78 MoM, P = 0.11), and 47,XX,i(22)(p10) (0.18 MoM, P = 0.08) were not statistically different from the controls. A model including maternal age, nuchal translucency, and PlGF could have identified all (95% CI 83%-100%) cases of trisomy 21 and six of the other fetal aneuploidies (75%) at a false-positive rate of 9%. CONCLUSION: Low first trimester PlGF is associated with an increased risk of fetal aneuploidy. PlGF combined with first trimester ultrasound (nuchal translucency, uterine artery Doppler, and early fetal anatomy) could identify not only women at high risk for preeclampsia, but also fetuses at high risk of aneuploidy for optimal further testing (non-invasive testing for common aneuploidy screening or chorionic villus sampling for full screening and diagnosis).

Does Low PAPP-A Predict Adverse Placenta-Mediated Outcomes in a Low-Risk Nulliparous Population? the Great Obstetrical Syndromes (GOS) Study.

OBJECTIVE: First-trimester low concentration of pregnancy-associated plasma protein A (PAPP-A) has been associated with adverse perinatal outcomes in high-risk populations. This study aimed to estimate the ability of PAPP-A to identify adverse outcomes in a low-risk population. METHODS: The study investigators recruited nulliparous women with singleton pregnancy at their 11-13-week ultrasound scan. Serum samples were collected, and maternal PAPP-A concentration was measured using the B⋅R⋅A⋅H⋅M⋅S PAPP-A KRYPTOR (ThermoFisher Scientific, Hennigsdorf, Germany) automated assay. PAPP-A was reported in multiple of median (MoM) adjusted for GA. Participants were followed until delivery for pregnancy outcomes including preeclampsia (PE), SGA <3rd percentile, and fetal death. Receiver operating characteristic curves with the area under the curve (AUC) were used to evaluate the predictive value of PAPP-A. The investigators calculated the detection rates (DRs) and positive predictive values (PPVs) of a PAPP-A < 0.4 MoM. RESULTS: The study investigators recruited 4739 eligible participants at a mean GA of 13 ± 6 weeks. The investigators observed 232 (4.9%) cases of PE, 84 (1.8%) cases of SGA, and 14 (0.3%) fetal deaths. PAPP-A was moderately associated with PE (AUC 0.57; 95% CI 0.53-0.61) and SGA (AUC 0.62; 95% CI 0.56-0.69), but not with fetal death (AUC 0.43; 95% CI 0.23-0.63). PAPP-A < 0.4 MoM was observed in 364 (7.7%) participants and had poor predictive values for PE (DR 9.8%; PPV 6.3%), SGA (DR 18.1%; PPV 4.4%), and fetal death (DR 21.4%; PPV 0.9%). CONCLUSION: Isolated first trimester PAPP-A has a limited predictive value for adverse pregnancy outcomes (other than trisomies). Low PAPP-A (<0.4 MoM) should be used in combination with other markers for the prediction of PE, SGA, or fetal death, and it does not constitute an indication for low-dose aspirin.

Maternal Characteristics for the Prediction of Preeclampsia in Nulliparous Women: The Great Obstetrical Syndromes (GOS) Study.

OBJECTIVE: Low-dose aspirin started in early pregnancy significantly reduces the risk of preeclampsia (PE) in high-risk women, especially preterm PE. This study aimed to evaluate the influence of maternal characteristics on the risk of PE in nulliparous women. METHODS: The Great Obstetrical Syndromes (GOS) study recruited nulliparous women with singleton pregnancies at 11 to 13 weeks. The following maternal characteristics were collected: age, BMI, ethnicity, chronic diseases, smoking, and assisted reproductive technologies. Relative weight analyses were conducted, and predictive multivariate proportional hazard models were constructed. Receiver operating characteristic curve analyses with their area under the curve (AUC) were used to evaluate the value of each factor for the prediction of PE and preterm PE. The study also evaluated the SOGC guidelines for identification of women at high risk of PE. RESULTS: Of 4739 participants, 232 (4.9%) developed PE, including 30 (0.6%) with preterm PE. In univariate analyses, only BMI was significantly associated with the risk of PE (AUC 0.60; 95% CI 0.55-0.65) and preterm PE (AUC 0.64; 95% CI 054-0.73). Adding other maternal characteristics to BMI had a non-significant and marginal impact on the discriminative ability to the models for PE (AUC 0.62; 95% CI 0.58-0.66) and preterm PE (AUC 0.65; 95% CI 0.56-0.74). At a false-positive rate of 10%, maternal characteristics could have predicted 23% of PE and 19% of preterm PE. The SOGC guidelines were not discriminant for PE (detecting 96% of PE and 93% of preterm PE with a 94% false-positive rate). CONCLUSION: In nulliparous women, BMI is the most discriminant maternal characteristic for the prediction of PE. Maternal characteristics should not be used alone to identify nulliparous women at high risk of PE.

Cell-Free DNA-Based Non-invasive Prenatal Screening for Common Aneuploidies in a Canadian Province: A Cost-Effectiveness Analysis.

OBJECTIVE: Yearly, 450 000 pregnant Canadians are eligible for voluntary prenatal screening for trisomy 21. Different screening strategies select approximately 4% of women for invasive fetal chromosome testing. Non-invasive prenatal testing (NIPT) using maternal blood cell-free DNA could reduce those invasive procedures but is expensive. This study evaluated the cost-effectiveness of NIPT strategies compared with conventional strategies. METHODS: This study used a decision analytic model to estimate the cost-effectiveness of 13 prenatal screening strategies for fetal aneuploidies: six frequently used strategies, universal NIPT, and six strategies incorporating NIPT as a second-tier test. The study considered a virtual cohort of pregnant women of similar size and age as women in Quebec. Model data were obtained from published sources and government databases. The study predicted the number of chromosomal anomalies detected (trisomies 21, 13, and 18), invasive procedures and euploid fetal losses, direct costs, and incremental cost-effectiveness ratios. RESULTS: Of the 13 strategies compared, eight identified fewer cases at a higher cost than at least one of the remaining five strategies. Integrated serum screening with conditional NIPT had the lowest cost, and the cost per case detected was $63 139, with a 90% reduction of invasive procedures. The number of cases identified was improved with four other screening strategies, but with increasing of incremental costs per case (from $61 623 to $1 553 615). Results remained robust, except when NIPT costs and risk cut-offs varied. CONCLUSION: NIPT as a second-tier test for high-risk women is likely to be cost-effective as compared with screening algorithms not involving NIPT.

Genomics-based non-invasive prenatal testing for detection of fetal chromosomal aneuploidy in pregnant women.

BACKGROUND: Common fetal aneuploidies include Down syndrome (trisomy 21 or T21), Edward syndrome (trisomy 18 or T18), Patau syndrome (trisomy 13 or T13), Turner syndrome (45,X), Klinefelter syndrome (47,XXY), Triple X syndrome (47,XXX) and 47,XYY syndrome (47,XYY). Prenatal screening for fetal aneuploidies is standard care in many countries, but current biochemical and ultrasound tests have high false negative and false positive rates. The discovery of fetal circulating cell-free DNA (ccfDNA) in maternal blood offers the potential for genomics-based non-invasive prenatal testing (gNIPT) as a more accurate screening method. Two approaches used for gNIPT are massively parallel shotgun sequencing (MPSS) and targeted massively parallel sequencing (TMPS). OBJECTIVES: To evaluate and compare the diagnostic accuracy of MPSS and TMPS for gNIPT as a first-tier test in unselected populations of pregnant women undergoing aneuploidy screening or as a second-tier test in pregnant women considered to be high risk after first-tier screening for common fetal aneuploidies. The gNIPT results were confirmed by a reference standard such as fetal karyotype or neonatal clinical examination. SEARCH METHODS: We searched 13 databases (including MEDLINE, Embase and Web of Science) from 1 January 2007 to 12 July 2016 without any language, search filter or publication type restrictions. We also screened reference lists of relevant full-text articles, websites of private prenatal diagnosis companies and conference abstracts. SELECTION CRITERIA: Studies could include pregnant women of any age, ethnicity and gestational age with singleton or multifetal pregnancy. The women must have had a screening test for fetal aneuploidy by MPSS or TMPS and a reference standard such as fetal karyotype or medical records from birth. DATA COLLECTION AND ANALYSIS: Two review authors independently carried out study selection, data extraction and quality assessment (using the QUADAS-2 tool). Where possible, hierarchical models or simpler alternatives were used for meta-analysis. MAIN RESULTS: Sixty-five studies of 86,139 pregnant women (3141 aneuploids and 82,998 euploids) were included. No study was judged to be at low risk of bias across the four domains of the QUADAS-2 tool but applicability concerns were generally low. Of the 65 studies, 42 enrolled pregnant women at high risk, five recruited an unselected population and 18 recruited cohorts with a mix of prior risk of fetal aneuploidy. Among the 65 studies, 44 evaluated MPSS and 21 evaluated TMPS; of these, five studies also compared gNIPT with a traditional screening test (biochemical, ultrasound or both). Forty-six out of 65 studies (71%) reported gNIPT assay failure rate, which ranged between 0% and 25% for MPSS, and between 0.8% and 7.5% for TMPS.In the population of unselected pregnant women, MPSS was evaluated by only one study; the study assessed T21, T18 and T13. TMPS was assessed for T21 in four studies involving unselected cohorts; three of the studies also assessed T18 and 13. In pooled analyses (88 T21 cases, 22 T18 cases, eight T13 cases and 20,649 unaffected pregnancies (non T21, T18 and T13)), the clinical sensitivity (95% confidence interval (CI)) of TMPS was 99.2% (78.2% to 100%), 90.9% (70.0% to 97.7%) and 65.1% (9.16% to 97.2%) for T21, T18 and T13, respectively. The corresponding clinical specificity was above 99.9% for T21, T18 and T13.In high-risk populations, MPSS was assessed for T21, T18, T13 and 45,X in 30, 28, 20 and 12 studies, respectively. In pooled analyses (1048 T21 cases, 332 T18 cases, 128 T13 cases and 15,797 unaffected pregnancies), the clinical sensitivity (95% confidence interval (CI)) of MPSS was 99.7% (98.0% to 100%), 97.8% (92.5% to 99.4%), 95.8% (86.1% to 98.9%) and 91.7% (78.3% to 97.1%) for T21, T18, T13 and 45,X, respectively. The corresponding clinical specificities (95% CI) were 99.9% (99.8% to 100%), 99.9% (99.8% to 100%), 99.8% (99.8% to 99.9%) and 99.6% (98.9% to 99.8%). In this risk group, TMPS was assessed for T21, T18, T13 and 45,X in six, five, two and four studies. In pooled analyses (246 T21 cases, 112 T18 cases, 20 T13 cases and 4282 unaffected pregnancies), the clinical sensitivity (95% CI) of TMPS was 99.2% (96.8% to 99.8%), 98.2% (93.1% to 99.6%), 100% (83.9% to 100%) and 92.4% (84.1% to 96.5%) for T21, T18, T13 and 45,X respectively. The clinical specificities were above 100% for T21, T18 and T13 and 99.8% (98.3% to 100%) for 45,X. Indirect comparisons of MPSS and TMPS for T21, T18 and 45,X showed no statistical difference in clinical sensitivity, clinical specificity or both. Due to limited data, comparative meta-analysis of MPSS and TMPS was not possible for T13.We were unable to perform meta-analyses of gNIPT for 47,XXX, 47,XXY and 47,XYY because there were very few or no studies in one or more risk groups. AUTHORS' CONCLUSIONS: These results show that MPSS and TMPS perform similarly in terms of clinical sensitivity and specificity for the detection of fetal T31, T18, T13 and sex chromosome aneuploidy (SCA). However, no study compared the two approaches head-to-head in the same cohort of patients. The accuracy of gNIPT as a prenatal screening test has been mainly evaluated as a second-tier screening test to identify pregnancies at very low risk of fetal aneuploidies (T21, T18 and T13), thus avoiding invasive procedures. Genomics-based non-invasive prenatal testing methods appear to be sensitive and highly specific for detection of fetal trisomies 21, 18 and 13 in high-risk populations. There is paucity of data on the accuracy of gNIPT as a first-tier aneuploidy screening test in a population of unselected pregnant women. With respect to the replacement of invasive tests, the performance of gNIPT observed in this review is not sufficient to replace current invasive diagnostic tests.We conclude that given the current data on the performance of gNIPT, invasive fetal karyotyping is still the required diagnostic approach to confirm the presence of a chromosomal abnormality prior to making irreversible decisions relative to the pregnancy outcome. However, most of the gNIPT studies were prone to bias, especially in terms of the selection of participants.

Newborn Screening for Hereditary Tyrosinemia Type I in Québec: Update.

Hereditary tyrosinemia type I (HTI) is a rare autosomal recessive disorder caused by a fumarylacetoacetate hydrolase (FAH) deficiency. If untreated, its acute form is characterized by hepatic failure, renal dysfunction and neurological crisis, and may lead to death. Due to a genetic founder effect in the French-Canadian population, the prevalence of HTI is increased in the province of Quebec (1/19 819), with the IVS12 + 5G>A (1062 + 5G>A) splice site mutation responsible for more than 90% of mutated alleles. Universal newborn screening for (HT1) was thus established in 1970, and close to four million infants have been tested so far, allowing to identify 185 of the 190 affected newborns. During the 1970-1997 period, 2,249,000 newborns were screened at 3-7 days of life on dried filter paper blood spots by tyrosine (Tyr) concentration followed by indirect colorimetric semi-quantitative and quantitative (Q) succinylacetone (SA) testing (red blood cells δ-aminolevulinate dehydratase inhibition), with immunoreactive FAH as the confirmatory test. This approach allowed to identify 118 of 123 affected newborns. In 1998, owing to earlier hospital discharge and increased rate of breastfeeding, four cases were missed within the same year as the discriminating power of blood Tyr became inadequate. Thus, the screening algorithm was modified: indirect semi-quantitative SA measurement became the first-tier test between 1998 and 2014, and direct SA measurement by tandem mass spectrometry (MS/MS) was implemented in 2014, followed by indirect quantitative SA measurement as second tier test. Confirmation is performed by plasmatic amino acid profile and molecular testing. During the 1998-2016 period, more than 1,5 million neonates have been tested (90% sampled between 24 and 48 h of life): 67 of the 67 HTI cases were identified. Both indirect and direct SA measurement as the initial HTI screening test proved to be highly sensitive and specific, with positive and negative predicting value of 79% and 100% respectively.

Vitamin D Status and Gestational Diabetes: Effect of Smoking Status during Pregnancy.

BACKGROUND: Vitamin D status, as measured by serum 25-hydroxyvitamin D (25(OH)D), has been shown in some studies to be inversely associated with gestational diabetes risk. Recently, it has been suggested that maternal smoking status may modify this relationship. We explored the association between 25(OH)D concentration and gestational diabetes and determined if there was an interaction between smoking and 25(OH)D. METHODS: A nested case-control study was conducted in Halifax, Nova Scotia and Quebec City, Quebec. Women were recruited before 20 weeks gestation and 25(OH)D was measured. Cases were women who developed gestational diabetes and controls were frequency matched to cases on study site, gestational age at blood draw, and season and year of blood draw. Logistic regression models estimated adjusted odds ratios (aOR) and 95% confidence intervals (CI). Models were tested for multiplicative and additive interaction, which was estimated by relative excess risk due to interaction (RERI). RESULTS: The study included 395 gestational diabetes cases and 1925 controls. Women who smoked during pregnancy and had 25(OH)D concentrations <30 nmol/L had an aOR = 3.73 [95% CI 1.95, 7.14] compared to non-smokers with 25(OH)D concentrations ≥50 nmol/L. Additive interaction was detected between smoking status and 25(OH)D [RERI = 2.44, 95% CI 0.03, 4.85]. CONCLUSION: Our study supports the inverse association of vitamin D status with gestational diabetes risk, particularly among women who smoke during pregnancy. More research is needed to confirm this finding and, if confirmed, to determine the mechanism by which the combined effect of smoking and low vitamin D status increases the risk of developing gestational diabetes.

Early prediction of gestational diabetes: a practical model combining clinical and biochemical markers.

BACKGROUND: Gestational diabetes (GDM) is usually diagnosed late in pregnancy, precluding early preventive interventions. This study aims to develop a predictive model based on clinical factors and selected biochemical markers for the early risk assessment of GDM. METHODS: Based on a prospective cohort of 7929 pregnant women from the Quebec City metropolitan area, a nested case-control study was performed including 264 women who developed GDM. Each woman who developed GDM was matched with two women with normal glycemic profile. Risk prediction models for GDM and GDM requiring insulin therapy were developed using multivariable logistic regression analyses, based on clinical characteristics and the measurement of three clinically validated biomarkers: glycated hemoglobin (HbA1c), sex hormone binding globulin (SHBG) and high-sensitivity C-reactive protein (hsCRP) measured between 14 and 17 weeks of gestation. RESULTS: HbA1c and hsCRP were higher and SHBG was lower in women who developed GDM (p<0.001). The selected model for the prediction of GDM, based on HbA1c, SHBG, BMI, past history of GDM, family history of diabetes and soft drink intake before pregnancy yielded an area under the ROC curve (AUC) of 0.79 (0.75-0.83). For the prediction of GDM requiring insulin therapy, the selected model including the same six variables yielded an AUC of 0.88 (0.84-0.92) and a sensitivity of 68.9% at a false-positive rate of 10%. CONCLUSIONS: A simple model based on clinical characteristics and biomarkers available early in pregnancy could allow the identification of women at risk of developing GDM, especially GDM requiring insulin therapy.

Periodontal Disease and Adverse Pregnancy Outcomes: A Prospective Study in a Low-Risk Population.

BACKGROUND: Periodontal disease has been associated with systemic inflammation and adverse pregnancy outcomes, including preeclampsia and preterm birth. OBJECTIVE: To examine the relationship between periodontal disease in early pregnancy and the risk of amniotic inflammation, preterm birth, and preeclampsia. METHODS: We performed a prospective cohort study of women undergoing amniocentesis for fetal karyotype between 15 and 24 weeks' gestation. Participants underwent periodontal examination by a certified dentist, and a sample of amniotic fluid was collected. Periodontal disease was defined as the presence of one or more sites with probing depths ≥ 4 mm and ≥ 10% bleeding on probing. Matrix metalloproteinase-8 and interleukin-6 concentrations in the amniotic fluid were measured. Medical charts were reviewed for perinatal outcomes. Univariate and multivariate logistic regression analyses were used to assess the association between periodontal disease and adverse pregnancy outcomes. RESULTS: We recruited 273 women at a median gestational age of 16 weeks (range 15 to 24), and 258 (95%) agreed to undergo periodontal examination. Periodontal disease was observed in 117 of the participants (45%). We observed no significant association between periodontal disease and preterm birth (relative risk [RR] 2.27; 95% CI 0.74 to 6.96) or spontaneous preterm birth (RR 0.90; 95% CI 0.20 to 4.11). However, women with periodontal disease were more likely to develop preeclampsia, and this association remained significant after adjustment for potential confounders (adjusted RR 5.89; 95% CI 1.24 to 28.05). Periodontal disease was not associated with significant differences in the intra-amniotic concentration of matrix metalloproteinase-8 (13.0 ± 46.6 vs 5.7 ± 10.4 ng/mL, P = 0.098) or interleukin-6 (3.3 ± 20.3 vs 1.0 ± 1.6 ng/mL, P = 0.23), although a non-significant trend was observed. CONCLUSION: Periodontal disease is associated with preeclampsia but not with spontaneous preterm birth. The current study cannot exclude an association between periodontal disease and intra-amniotic inflammation.