Dépistage de la trisomie 21 par les marqueurs sériques maternels : justification des commentaires appliqués par les biologistes

Usefulness of early morphological ultrasound in association with cell-free DNA testing in case of atypical serum markers in first trimester of pregnancy: A retrospective study over 5 years

BACKGROUND

Early morphologic ultrasound, generally carried out in case of atypical first trimester serum markers (PAPP-A and/or free hCGβ <0.30 MoM), has not been re-evaluated since the possibility of performing a cell-free fetal DNA analysis in this indication. Our objective was to evaluate the usefulness of early morphological ultrasound in case of atypical profile of serum markers performed in association with Non-Invasive Prenatal Testing (NIPT).

METHODS

This was a single-center retrospective study in a tertiary maternity. Between January 2017 and December 2021, women with an atypical first trimester serum markers and low/intermediate risk for trisomy 21 (<1/50) were included. The clinical data, results of first trimester serum markers, NIPT, early morphological ultrasound and subsequent ultrasounds and other investigations (amniocentesis, pregnancy outcomes) were analyzed.

RESULTS

After exclusion of women with high-risk of trisomy 21 and lost to follow-up, 163 women were included. In 72 % of cases (117/163), women had a low risk of trisomy 21, and 39 % (59/163) had an early morphological ultrasound. Early morphological ultrasound was useful to detect severe IUGR leading to the suspicion of triploidy (3/163, 1.8 %). In all other situations, it did not allow earlier management. After analysis of the 3 triploidy cases, a collapsed profile for both serum markers was demonstrated (<0.25 MoM).

CONCLUSIONS

Systematic early morphological ultrasound in case of an atypical serum marker profile seems useless considering the performance of NIPT. An ultrasound restricted to women with both markers below 0.25 MoM would allow the early detection of triploidy.

Multiple pregnancy with complete hydatidiform mole and coexisting normal fetus in a retrospective cohort of 141 patients

BACKGROUND

Multiple pregnancy with a complete hydatidiform mole and a normal fetus is prone to severe obstetrical complications and malignant transformation after birth. Prognostic information is limited for this rare form of gestational trophoblastic disease.

OBJECTIVE

This study aimed to determine obstetrical outcomes and the risk of gestational trophoblastic neoplasia in women with multiple pregnancy with complete hydatidiform mole and coexisting normal fetus, and to identify risk factors for poor obstetrical and oncological outcomes to improve patient information and management.

STUDY DESIGN

This was a retrospective national cohort study of 11,411 records from the French National Center for Trophoblastic Disease registered between January 2001 and January 2022.

RESULTS

Among 11,411 molar pregnancies, 141 involved histologically confirmed multiple pregnancy with complete hydatidiform mole and coexisting normal fetus. Roughly a quarter of women (23%; 33/141) decided to terminate pregnancy because of presumed poor prognosis or by choice. Among the 77% of women (108/141) who continued their pregnancy, 16% of pregnancies (17/108) were terminated because of maternal complications, and 37% (40/108) ended in spontaneous miscarriage before 24 weeks' gestation. The median gestational age at delivery in the remaining 47% of pregnancies (51/108) was 32 weeks. The overall neonatal survival rate at day 8 was 36% (39/108; 95% confidence interval, 27-46) after excluding elective pregnancy terminations. Patients with free beta human chorionic gonadotropin levels <10 multiples of the median were significantly more likely to reach 24 weeks' gestation compared with those with free beta human chorionic gonadotropin levels >10 multiples of the median (odds ratio, 7.0; 95% confidence interval, 1.3-36.5; P=.022). A lower free beta human chorionic gonadotropin level was also associated with better early neonatal survival (the median free beta human chorionic gonadotropin level was 9.4 multiples of the median in patients whose child was alive at day 8 vs 20.0 multiples of the median in those whose child was deceased; P=.02). The overall rate of gestational trophoblastic neoplasia after a multiple pregnancy with complete hydatidiform mole and a normal fetus was 26% (35/136; 95% confidence interval, 19-34). All 35 patients had low-risk International Federation of Gynecology and Obstetrics scores, and the cure rate was 100%. Termination of pregnancy on patient request was not associated with lower risk of gestational trophoblastic neoplasia. Maternal complications such as preeclampsia and postpartum hemorrhage were not associated with higher risk of gestational trophoblastic neoplasia, and neither were high human chorionic gonadotropin levels or newborn survival at day 8.

CONCLUSION

Multiple pregnancy with complete hydatidiform mole and coexisting fetus carries a high risk of obstetrical complications. In patients who continued their pregnancy, approximately one-third of neonates were alive at day 8, and roughly 1 in 4 patients developed gestational trophoblastic neoplasia. Therefore, the risk of malignant transformation appears to be higher compared with singleton complete moles. Low levels of free beta human chorionic gonadotropin may be indicative of better early neonatal survival, and this relationship warrants further study.

[Discordant Down syndrome risk calculation with low maternal serum markers: About five cases of digynic triploidies]

OBJECTIVE

We compare the risk of Down syndrome among five patients carrying a foetus with digynic triploidy and suggest a course of action for these particular serological profiles.

METHODS

The concentrations of the different markers used are transformed into multiples of the median by using each of the three software types present on the French market which then determine the risk of Down syndrome.

RESULTS

For comparable biochemical and ultrasound profiles, the risk of Down syndrome turns out to be vastly different depending on the type of software employed. The relevance of an immediate diagnostic procedure, of a cell free DNA test or of a basic ultrasound follow-up then arises, leading to a potentially variable care pathway for the patient.

CONCLUSIONS

This study confirms that for this type of biochemical profile, the laboratory's advisory service is fundamental, that a control ultrasound is essential and that an invasive procedure must be used almost invariably due to the extremely substantial risk factors.

Association between blastocyst morphology and maternal first trimester serum markers in ongoing pregnancies obtained after single fresh blastocyst transfer

OBJECTIVE

Is there an association between blastocyst morphology and maternal first trimester serum markers in In Vitro Fertilization (IVF) pregnancies obtained after fresh single blastocyst transfer?

STUDY DESIGN

This bi-centric retrospective study was conducted between January 2012 and August 2018. We included 122 women aged from 18 to 43 years-old, whose pregnancy progressed at least beyond 13 weeks after a single blastocyst transfer and who participated in the first trimester combined screening test. Day 5 and day 6 blastocysts were evaluated according to Gardner and Schoolcraft classification. Patients were classified into three groups according to blastocysts morphological quality: excellent (≥ 3AA), good (3-6AB, 3-6BA, B2), and medium to poor (3-6BB, 3-6AC, 3-6CA, B1, 3-6CB, 3-6BC). First trimester serum markers were measured in maternal blood between 9 and 11 + 6 gestational weeks. Univariate and multivariate analyses were performed.

RESULTS

Female body mass index, smoking status, type of infertility, geographical origin, anti-mullerian hormone level, ovarian stimulation characteristics, pregnancy outcomes and obstetrical complications were comparable between the three groups. Patient's age was not distributed evenly across groups, with women in group "Medium to Poor" appearing to be slightly younger than in other groups. There were no significant differences in mean first trimester serum markers between the three groups (PAPP-A: excellent: 1.23 ± 0.59 MoM; good: 1.45 ± 0.71 MoM; medium to poor: 1.22 ± 0.52 MoM; p = 0,20; free beta-HCG: excellent: 1.66 ± 1.38 MoM; good: 1.19 ± 0.76 MoM; medium to poor: 1.81 ± 1.34 MoM; p = 0,12). No significant difference was found either between mean first trimester serum markers and inner cell mass morphology (PAPP-A: grade A: 1.23 ± 0.58 MoM; grade B: 1.26 ± 0.60 MoM; medium to poor: 1.64 ± 0.87 MoM; p = 0,67 ; free beta-HCG: grade A: 1.66 ± 1.36 MoM; grade B: 1.52 ± 1.10 MoM; medium to poor: 1.57 ± 0.39 MoM p = 0,60), trophectoderm cells morphology (PAPP-A: grade A: 1.25 ± 0.63 MoM; grade B: 1.26 ± 0.51 MoM; medium to poor: not comparable; p = 0,66; free beta-HCG: grade A: 1.60 ± 1.34 MoM; grade B: 1.69 ± 1.14 MoM; medium to poor: not comparable; p = 0,25), or blastocoel expansion (PAPP-A: B1: 1.08 ± 0.51MoM; B2: 1.57 ± 0.70 MoM; B3: 1.26 ± 0.61 MoM; B4: 1.28 ± 0.62 MoM; B5: 1.04 ± 0.38 MoM; p = 0,22; free beta-HCG: B1: 2.01 ± 1.88 MoM; B2: 1.07 ± 0.49 MoM; B3: 1.43 ± 0.87 MoM; B4: 1.68 ± 1.28 MoM ; B5: 1.82 ± 2.03 MoM; p = 0,48). After adjustment on potential confounding factors (female age, type of gonadotropin, parity, number of oocytes retrieved and occurrence of ovarian hyperstimulation syndrome), we did not observe any association between PAPP-A or free beta-HCG levels and blastocyst morphology.

CONCLUSION

Our study concluded that first trimester serum markers were not associated with blastocyst morphological characteristics. Although this needs further confirmation, this suggests that blastocyst morphology would not have an impact on placentation. Therefore, these findings are reassuring for couples undergoing IVF and blastocyst transfer.

Usefulness and reliability of cell free fetal DNA screening for main trisomies in case of atypical profile on first trimester maternal serum screening

Background

Patients with atypical values of HCG and/or PAPP-A are at higher risk of chromosomal abnormality and vascular complications of pregnancy. The performance of cfDNA in this particular population has not yet been evaluated.

Objectives

The primary objective was to evaluate the usefulness and reliability of cfDNA in screening for trisomy 21, 18 and 13 for patients with HCG < 0.25 multiple of median (MoM), HCG > 5.0 MoM and/or PAPP-A < 0.25 MoM, PAPP-A > 2.5 MoM. The secondary objective was to evaluate the contribution of cfDNA assay for the prediction of pregnancy’s vascular complications.

Method

Between June 2016 and July 2017, we analysed a women cohort from all over France who had at least one first trimester serum biomarker outside of normal range, in a retrospective, observational and multicentre study. Patients were included if they had a single pregnancy, normal first trimester ultrasound examination, whatever the result of the combined first trimester screening test was. The cfDNA was analysed by massive parallel sequencing technique. The accuracy of cfDNA assay was evaluated by calculation of sensitivity and specificity, and multivariate regression analysis was used to search for predictive factors for pregnancy’s vascular complications.

Results

Among the 498 patients who underwent a cfDNA assay in this context, twenty-one (4.2%) were excluded because of loss to follow-up. Out of 477, test failure occurred for four patients initially, reduced to two patients (0.4%) after redrawn. CfDNA was positive for Trisomy 21 (n = 19), Trisomy 18 (n = 6) and Trisomy 13 (n = 1) and negative in 449. The sensitivity of cfDNA assay for trisomy 21 screening was 100% (19/19) (IC 95% 82.4–100) and specificity 100% (458/458) (IC 95% 99.2–100). Among the 447 patients included for prediction of vascular complications, there were four cases of pregnancy induced hypertension and 10 cases of preeclampsia, for which no predictive factor was identified. Intra Uterine growth restriction under 5th percentile (n = 44, 9.8%) was significantly associated with a low fetal fraction (OR = 0.87, IC 95% 0.79–0.96, p = 0.006).

Conclusion

cfDNA assay is an effective and reliable tool for women with atypical profile of first trimester serum biomarkers.

Effect of Cell-Free DNA Screening vs Direct Invasive Diagnosis on Miscarriage Rates in Women With Pregnancies at High Risk of Trisomy 21: A Randomized Clinical Trial

IMPORTANCE

Cell-free DNA (cfDNA) tests are increasingly being offered to women in the first trimester of pregnancies at a high risk of trisomy 21 to decrease the number of required invasive fetal karyotyping procedures and their associated miscarriages. The effect of this strategy has not been evaluated.

OBJECTIVE

To compare the rates of miscarriage following invasive procedures only in the case of positive cfDNA test results vs immediate invasive testing procedures (amniocentesis or chorionic villus sampling) in women with pregnancies at high risk of trisomy 21 as identified by first-trimester combined screening.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial conducted from April 8, 2014, to April 7, 2016, in 57 centers in France among 2111 women with pregnancies with a risk of trisomy 21 between 1 in 5 and 1 in 250 following combined first-trimester screening.

INTERVENTIONS

Patients were randomized to receive either cfDNA testing followed by invasive testing procedures only when cfDNA tests results were positive (n = 1034) or to receive immediate invasive testing procedures (n = 1017). The cfDNA testing was performed using an in-house validated method based on next-generation sequencing.

MAIN OUTCOMES AND MEASURES

The primary outcome was number of miscarriages before 24 weeks' gestation. Secondary outcomes included cfDNA testing detection rate for trisomy 21. The primary outcome underwent 1-sided testing; secondary outcomes underwent 2-sided testing.

RESULTS

Among 2051 women who were randomized and analyzed (mean age, 36.3 [SD, 5.0] years), 1997 (97.4%) completed the trial. The miscarriage rate was not significantly different between groups at 8 (0.8%) vs 8 (0.8%), for a risk difference of -0.03% (1-sided 95% CI, -0.68% to ∞; P = .47). The cfDNA detection rate for trisomy 21 was 100% (95% CI, 87.2%-100%).

CONCLUSIONS AND RELEVANCE

Among women with pregnancies at high risk of trisomy 21, offering cfDNA screening, followed by invasive testing if cfDNA test results were positive, compared with invasive testing procedures alone, did not result in a significant reduction in miscarriage before 24 weeks. The study may have been underpowered to detect clinically important differences in miscarriage rates.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02127515.

[Overview of feelings and practices of gynecologists and obstetricians for the noninvasive prenatal testing in France]

OBJECTIVES

To evaluate the feelings and practices of French obstetrician-gynecologists in prescribing the noninvasive prenatal testing (NIPT) before the release of the French High Authority of Health recommendations.

METHODS

Descriptive, declarative and transversal study, analyzing the feelings and practices of obstetrician-gynecologists, members of the French College of Gynecologists and Obstetricians (CNGOF) between February and May 2017 using an online questionnaire. Practitioners' feedback was self-assessed for several clinical situations using a numerical scale ranging from 1 to 10. This experience was rated as "good" (grades 6 to 10) or "bad" (grades 1-5).

RESULTS

Overall, 529 practitioners (29.2%) of 1812 CNGOF members, answered the online questionnaire. A "good" feeling was found for more than 65% of the practitioners audited. Feelings were significantly better for obstetricians, sonographers (P<0.05) and CPDPN members (P=0.003) compared to other practitioners. Situations where the DPNI was proposed "systematically" were risks greater than 1/250 (70.9%), between 1/250 and 1/500 (59.4%), greater than 1/250 associated with history of spontaneous miscarriages and/or fetal death in utero (66%), greater than 1/250 associated with pregnancy resulting from PMA (68.3%), history of fetal aneuploidy (54%) and a parent carrying a Robertsonian translocation (51.6%).

CONCLUSION

This study highlights a good overall feeling of the practitioners with the NIPT.

[The noninvasive prenatal testing for Down's Syndrome. Retrospective study of 8821 patients]

OBJECTIVE

To demonstrate the decrease in intrauterine invasive procedures through analysis of DNA fetoplacental free circulating in maternal blood: Non Invasive Prenatal Test (NIPT), in Prenatal Diagnosis Center of American Hospital of Paris (AHP).

MATERIALS AND METHODS

Retrospective descriptive study of 8821 patients in Prenatal Diagnosis Center at the AHP between 01/01/2012 and 09/25/2014. The NIPT is available to patients since 1st January 2013.

RESULTS

The number of invasive procedures decreased significantly (P<0.0001) between 2012 (n=1177, i.e. 42 % of the global activity of the Prenatal Diagnosis Center at the AHP in 2012) and 2013 (n=987 or 28.5 %) and between 2013 and 2014 (n=599 or 23.4 %). The NIPT calculated performance statistics are: sensitivity≥99.9 %; specificity=99.8 %; Positive Predictive Value=90.4 %; Negative Predictive Value≥99.9 %; False Positives=3. While the actual screening statistic values are: sensitivity≥95.4 %; specificity=82.5 %; Positive Predictive Value=6.5 %; Negative Predictive Value=99.9 %; False Positives=1197. The NIPT has reduced the number of invasive procedures at the Prenatal Diagnosis Center at the AHP. The NIPT performances are superior to those of the actual screening.