Impact of the delay between fetal death and delivery on the success of postmortem ultrasound following termination of pregnancy

OBJECTIVE

To evaluate the impact of the delay between fetal death and delivery on the nondiagnostic rates of post-mortem ultrasound (PM-US), following the termination of pregnancy (TOP).

METHODS

We reviewed 204 cases of fetal two-dimensional PM-US performed in our center as part of a post-mortem imaging research program, over the last 5 years. Informed consent was obtained from the parents for all cases. PM-US was performed and reported according to a prespecified template with operators blinded to the prenatal diagnosis. In order to calculate the precise delay between the fetal death and the delivery, we included 107 fetal TOP's ≥ 20 weeks of gestational age (GA), where feticide was performed using an injection of lidocaine 2% prior to induction of labor. Logistic regression analysis was conducted to analyze the impact of delay between fetal death and delivery (in hours), the GA at TOP (in weeks) and the method of feticide (intracardiac versus intraumbilical injection) on the PMUS nondiagnostic rates.

RESULTS

The delay between fetal death and delivery increased the nondiagnostic rate of PM-US for cerebral examinations (OR: 1.04, IC 95%: 1.01-1.08, p < .05). For PM-US cardiac examination, the delay did not influence the nondiagnostic rate. However, GA (OR: 1.25, IC 95%: 1.10-1.46, p < .01) and feticide with intracardiac injection (OR: 4.29, IC 95%: 1.68-12.02, p < .01) were associated with higher nondiagnostic rates. For noncardiac thoracic and abdominal examinations, none of the studied variables influenced the nondiagnostic rate.

CONCLUSION

The success rate of cerebral PM-US was influenced by the delay between fetal death and delivery, suggesting a possible advantage of performing the feticide closer to the delivery where the examination of the brain is planned. For cardiac abnormalities, feticide by intraumbilical, rather than intracardiac injection improves diagnostic rates of cardiac PM-US.

Magnetic resonance imaging for prenatal estimation of birthweight in pregnancy: review of available data, techniques, and future perspectives

Fetuses at the extremes of growth abnormalities carry a risk of perinatal morbidity and death. Their identification traditionally is done by 2-dimensional ultrasound imaging, the performance of which is not always optimal. Magnetic resonance imaging superbly depicts fetal anatomy and anomalies and has contributed largely to the evaluation of high-risk pregnancies. In 1994, magnetic resonance imaging was introduced for the estimation of fetal weight, which is done by measuring the fetal body volume and converting it through a formula to fetal weight. Approximately 10 studies have shown that magnetic resonance imaging is more accurate than 2-dimensional ultrasound imaging in the estimation of fetal weight. Yet, despite its promise, the magnetic resonance imaging technique currently is not implemented clinically. Over the last 5 years, this technique has evolved quite rapidly. Here, we review the literature data, provide details of the various measurement techniques and formulas, consider the application of the magnetic resonance imaging technique in specific populations such as patients with diabetes mellitus and twin pregnancies, and conclude with what we believe could be the future perspectives and clinical application of this challenging technique. The estimation of fetal weight by ultrasound imaging is based mainly on an algorithm that takes into account the measurement of biparietal diameter, head circumference, abdominal circumference, and femur length. The estimation of fetal weight by magnetic resonance imaging is based on one of the 2 formulas: (1) magnetic resonance imaging-the estimation of fetal weight (in kilograms)=1.031×fetal body volume (in liters)+0.12 or (2) magnetic resonance imaging-the estimation of fetal weight (in grams)=1.2083×fetal body volume (in milliliters)ˆ0.9815. Comparison of these 2 formulas for the detection of large-for-gestational age neonates showed similar performance for preterm (P=.479) and for term fetuses (P=1.000). Literature data show that the estimation of fetal weight with magnetic resonance imaging carries a mean or median relative error of 2.6 up to 3.7% when measurements were performed at <1 week from delivery; whereas for the same fetuses, the relative error at 2-dimensional ultrasound imaging varied between 6.3% and 11.4%. Further, in a series of 270 fetuses who were evaluated within 48 hours from birth and for a fixed false-positive rate of 10%, magnetic resonance imaging detected 98% of large-for-gestational age neonates (≥95th percentile for gestation) compared with 67% with ultrasound imaging estimates. For the same series, magnetic resonance imaging applied to the detection of small-for-gestational age neonates ≤10th percentile for gestation, for a fixed 10% false-positive rate, reached a detection rate of 100%, compared with only 78% for ultrasound imaging. Planimetric measurement has been 1 of the main limitations of magnetic resonance imaging for the estimation of fetal weight. Software programs that allow semiautomatic segmentation of the fetus are available from imaging manufacturers or are self-developed. We have shown that all of them perform equally well for the prediction of large-for-gestational age neonates, with the advantage of the semiautomatic methods being less time-consuming. Although many challenges remain for this technique to be generalized, a 2-step strategy after the selection of a group who are at high risk of the extremes of growth abnormalities is the most likely scenario. Results of ongoing studies are awaited (ClinicalTrials.gov Identifier # NCT02713568).

Profile of women choosing the Harmony® Prenatal Test

INTRODUCTION

The Harmony® Prenatal Test, a noninvasive cell-free DNA (cfDNA) method for major trisomies has been available since January 2013 at our unit, and tests were sent to the Ariosa Clinical Laboratory Improvement Amendments (CLIA) laboratory in California. From July 2017 onward, prenatal cfDNA has been reimbursed in Belgium for all pregnancies; however, since then samples are sent to a local laboratory. Little data are available on patient's profile and choices toward cfDNA and on the performance of local technology transfer centers. Areas covered: The profiles and choices of women regarding this test were evaluated. Further, the performance of cfDNA at the local laboratory was compared to the one in California. Our results showed that women from the Netherlands, as compared to Belgium, were more likely to undergo cfDNA testing for maternal request and would be less likely to undergo karyotyping if cfDNA were unavailable, therefore are better candidates for cfDNA testing, when this is used as first-line screening. Expert commentary: Our findings highlight the importance of conducting these types of studies, before decisions about clinical implementation are made by national governments and ministries of health.

Protocol for the prospective observational clinical study: estimation of fetal weight by MRI to PREdict neonatal MACROsomia (PREMACRO study) and small-for-gestational age neonates

INTRODUCTION

Macrosomia refers to growth beyond a specific threshold, regardless of gestational age. These fetuses are also frequently referred to as large for gestational age (LGA). Various cut-offs have been used but for research purposes, a cut-off above the 95th centile for birth weight is often preferred because it defines 90% of the population as normal weight. The use of centiles, rather than estimated weights, also accommodates preterm macrosomic infants, although most of the complications, maternal and fetal, arise during the delivery of large babies at term. This means that accurate identification of LGA fetuses (≥95th centile) may play an important role in guiding obstetric interventions, such as induction of labour or caesarean section. Traditionally, identification of fetuses suspected of macrosomia has been based on biometric measurements using two-dimensional (2D) ultrasound (US), yet this method is rather sub-optimal. We present a protocol (V.2.1, date 19 May 2016) for the estimation of fetal weight (EFW) by MRI to PREdict neonatal MACROsomia (PREMACRO study), which is a prospective observational clinical study designed to determine whether MRI at 36 + 0 to 36 + 6 weeks of gestation, as compared with 2D US, can improve the identification of LGA neonates ≥95th centile.

METHODS AND ANALYSIS

All eligible women attending the 36-week clinic will be invited to participate in the screening study for LGA fetuses ≥95th centile and will undergo US-EFW and MRI-EFW within minutes of each other. From these estimations, a centile will be derived which will be compared with the centile of birth weight used as the gold standard. Besides birth weight, other pregnancy and neonatal outcomes will be collected and analysed. The first enrolment for the study was in May 2016. As of September 2018, 2004 women have been screened and recruited to the study. The study is due to end in April 2019.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the International Conference on Harmonisation for good clinical practice and the appropriate regulatory requirement(s). A favourable ethical opinion was obtained from the Ethics Committee of the University Hospital Brugmann, reference number CE2016/44. Results will be published in peer-reviewed journals and disseminated at international conferences.

TRIAL REGISTRATION NUMBER

NCT02713568.

Postmortem examination of human fetuses: comparison of two-dimensional ultrasound with invasive autopsy

OBJECTIVE

To assess the diagnostic accuracy of postmortem ultrasound performed by operators blinded to prenatal findings and to invasive autopsy results in fetuses at different gestational ages and to investigate the effect of various parameters on its diagnostic success.

METHODS

We performed postmortem two-dimensional ultrasound examination, blinded to clinical details, on 163 fetuses at 13-42 weeks' gestation. Logistic regression analysis was used to investigate the effect of: (i) gestational age at postmortem ultrasound, (ii) presence of maceration and (iii) mode of death, on whether the exam succeeded or failed to reach a diagnosis. In 123 cases in which invasive autopsy was available, the diagnostic accuracy of ultrasound in detecting major organ abnormalities was evaluated, using invasive autopsy as the gold standard.

RESULTS

For the fetal brain, postmortem ultrasound exam was non-diagnostic in significantly more fetuses with maceration (39.5%; 17/43) vs those without maceration (20.0%; 24/120) (P = 0.013). For the fetal thorax, the exam was non-diagnostic in 34.1% (15/44) of fetuses < 20 weeks of gestation and in 10.9% (13/119) of fetuses ≥ 20 weeks (P < 0.001). For the heart and abdominal organs, there was no association between non-diagnostic postmortem ultrasound and the variables tested. For fetuses < 20 weeks, specificity of postmortem ultrasound examination was 83.3% for detection of anomalies of the brain, 68.6% for the thorax and 77.4% for the heart. For fetuses ≥ 20 weeks, sensitivity and specificity were, respectively, 61.9% and 74.2% for detection of anomalies of the brain, 29.5% and 87.0% for the thorax and 65.0% and 83.1% for the heart. For the fetal abdominal organs, sensitivity was 60.7% and specificity 75.8%, and postmortem ultrasound was particularly useful for detection of abnormalities of the kidneys, irrespective of gestational age.

CONCLUSION

Although maceration may lead to failure of postmortem ultrasound examination in some cases, this technique achieves diagnostically acceptable levels of accuracy for fetal brain and abdominal organs, compared with conventional autopsy. It may therefore play a role as a first-line examination before other virtual autopsy techniques are indicated. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Autoimmune disorders but not heparin are associated with cell-free fetal DNA test failure

Background

Recent studies have suggested a possible association between heparin treatment at the time of cell-free DNA (cfDNA) testing and a non-reportable result. However, these studies lack of proper methodology and had a low level of proof to firmly incriminate heparin. Our objective was to investigate further the relationship between heparin treatment and cfDNA test results.

Methods

Two complementary approaches were used for the demonstration. First, we conducted a retrospective analysis of a cohort of patients with a singleton pregnancy, screened for aneuploidies by using cfDNA, but with a non-reportable cfDNA result. We included patients between 2013 and 2016 including the patients from the DEPOSA study as controls. CfDNA testing was performed by massive parallel sequencing by using a whole-genome approach. A multiple logistic regression was used to account for the influence of the variables included. Second, we performed in vitro experiments on mimic samples containing increased concentrations of heparin.

Results

Of 9867 singleton pregnancies tested during the inclusion period, 58 (0.59%) had a non-reportable result and were compared to 295 control patients. Fifteen (25.9%) and 20 (6.8%) patients were treated with heparin in the group with a non-reportable cfDNA result and with a successful assay, respectively. In multivariable analysis, an increased calculated risk at the first-trimester combined screening (OR 28.8 CI 9.76–85.15, p < 0.001), maternal weight (OR 1.03, CI 1.01–1.06, p = 0.01), and the presence of an autoimmune disease (OR 10.38, CI 1.62–66.53, p = 0.01) were the only characteristics associated with a non-reportable result. In vitro experiments showed that heparin had no impact on fetal fraction measurement or the final result, no matter what the dose tested.

Conclusions

Treatment by heparin had no impact on cfDNA screening test for aneuploidies, while the presence of an autoimmune disorder is an independent predictor of a non-reportable result.

Screening for pre-eclampsia by maternal factors and biomarkers at 11-13 weeks' gestation

OBJECTIVE

To examine the performance of screening for early, preterm and term pre-eclampsia (PE) at 11-13 weeks' gestation by maternal factors and combinations of mean arterial pressure (MAP), uterine artery (UtA) pulsatility index (PI), serum placental growth factor (PlGF) and serum pregnancy-associated plasma protein-A (PAPP-A).

METHODS

The data for this study were derived from three previously reported prospective non-intervention screening studies at 11 + 0 to 13 + 6 weeks' gestation in a combined total of 61 174 singleton pregnancies, including 1770 (2.9%) that developed PE. Bayes' theorem was used to combine the prior distribution of gestational age at delivery with PE, obtained from maternal characteristics, with various combinations of biomarker multiples of the median (MoM) values to derive patient-specific risks of delivery with PE at < 37 weeks' gestation. The performance of such screening was estimated.

RESULTS

In pregnancies that developed PE, compared to those without PE, the MoM values of UtA-PI and MAP were increased and those of PAPP-A and PlGF were decreased, and the deviation from normal was greater for early than late PE for all four biomarkers. Combined screening by maternal factors, UtA-PI, MAP and PlGF predicted 90% of early PE, 75% of preterm PE and 41% of term PE, at a screen-positive rate of 10%; inclusion of PAPP-A did not improve the performance of screening. The performance of screening depended on the racial origin of the women; on screening by a combination of maternal factors, MAP, UtA-PI and PlGF and using a risk cut-off of 1 in 100 for PE at < 37 weeks in Caucasian women, the screen-positive rate was 10% and detection rates for early, preterm and term PE were 88%, 69% and 40%, respectively. With the same method of screening and risk cut-off in women of Afro-Caribbean racial origin, the screen-positive rate was 34% and detection rates for early, preterm and term PE were 100%, 92% and 75%, respectively.

CONCLUSION

Screening by maternal factors and biomarkers at 11-13 weeks' gestation can identify a high proportion of pregnancies that develop early and preterm PE. © 2018 Crown copyright. Ultrasound in Obstetrics & Gynecology © 2018 ISUOG.

Prenatal prediction of postnatal large-for-dates neonates using a simplified MRI method: comparison with conventional 2D ultrasound estimates

OBJECTIVE

To evaluate the performance of a simple semi-automated method for estimation of fetal weight (EFW) using magnetic resonance imaging (MRI) as compared with two-dimensional (2D) ultrasound (US) for the prediction of large-for-dates neonates.

METHODS

Data of two groups of women with singleton pregnancy between March 2011 and May 2016 were retrieved from our database and evaluated retrospectively: the first group included women who underwent US-EFW and MRI-EFW within 48 h before delivery and the second group included women who had these evaluations between 35 + 0 weeks and 37 + 6 weeks of gestation, more than 48 h before delivery. US-EFW was based on Hadlock et al. and MRI-EFW on the formula described by Baker et al. For MRI-EFW, planimetric measurement of the fetal body volume (FBV) was performed using a semi-automated method and the time required for measurement was noted. Outcome measure was the performance of MRI-EFW vs US-EFW in the prediction of large-for-dates neonates, both ≤ 48 h and > 48 h before delivery. Receiver-operating characteristics (ROC) curves for each method were compared using the DeLong method.

RESULTS

Of the 270 women included in the first group, 48 (17.8%) newborns had birth weight ≥ 90^th centile and 30 (11.1%) ≥ 95^th centile. The second group included 83 women, and nine (10.8%) newborns had birth weight ≥ 95^th centile. Median time needed for FBV planimetric measurements in all 353 fetuses was 3.5 (range, 1.5-5.5) min. The area under the ROC curve (AUC) for prediction of large-for-dates neonates by prenatal MRI performed within 48 h before delivery was significantly higher than that by US (for birth weight ≥ 90^th centile, difference between AUCs = 0.085, standard error (SE) = 0.020, P < 0.001; for birth weight ≥ 95^th centile, difference between AUCs = 0.036, SE = 0.014, P = 0.01). Similarly, MRI-EFW was better than US-EFW in predicting birth weight ≥ 95^th centile when both examinations were performed > 48 h prior to delivery (difference between AUCs = 0.077, SE = 0.039, P = 0.045).

CONCLUSION

MRI planimetry using our purpose-designed semi-automated method is not time-consuming. The predictive performance of MRI-EFW performed immediately prior to or remote from delivery is significantly better than that of US-EFW for the prediction of large-for-dates neonates. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Prediction and prevention of small-for-gestational-age neonates: evidence from SPREE and ASPRE

OBJECTIVES

To examine the effect of first-trimester screening for pre-eclampsia (PE) on the prediction of delivering a small-for-gestational-age (SGA) neonate and the effect of prophylactic use of aspirin on the prevention of SGA.

METHODS

The data for this study were derived from two multicenter studies. In SPREE, we investigated the performance of screening for PE by a combination of maternal characteristics and biomarkers at 11-13 weeks' gestation. In ASPRE, women with a singleton pregnancy identified by combined screening as being at high risk for preterm PE (> 1 in 100) participated in a trial of aspirin (150 mg/day from 11-14 until 36 weeks' gestation) compared to placebo. In this study, we used the data from the ASPRE trial to estimate the effect of aspirin on the incidence of SGA with birth weight < 10^th , < 5^th and < 3^rd percentile for gestational age. We also used the data from SPREE to estimate the proportion of SGA in the pregnancies with a risk for preterm PE of > 1 in 100.

RESULTS

In SPREE, screening for preterm PE by a combination of maternal factors, mean arterial pressure, uterine artery pulsatility index and serum placental growth factor identified a high-risk group that contained about 46% of SGA neonates < 10^th percentile born at < 37 weeks' gestation (preterm) and 56% of those born at < 32 weeks (early); the overall screen-positive rate was 12.2% (2014 of 16 451 pregnancies). In the ASPRE trial, use of aspirin reduced the overall incidence of SGA < 10^th percentile by about 40% in babies born at < 37 weeks' gestation and by about 70% in babies born at < 32 weeks; in babies born at ≥ 37 weeks, aspirin did not have a significant effect on incidence of SGA. The aspirin-related decrease in incidence of SGA was mainly due to its incidence decreasing in pregnancies with PE, for which the decrease was about 70% in babies born at < 37 weeks' gestation and about 90% in babies born at < 32 weeks. On the basis of these results, it was estimated that first-trimester screening for preterm PE and use of aspirin in the high-risk group would potentially reduce the incidence of preterm and early SGA by about 20% and 40%, respectively.

CONCLUSION

First-trimester screening for PE by the combined test identifies a high proportion of cases of preterm SGA that can be prevented by the prophylactic use of aspirin. © 2018 Crown copyright. Ultrasound in Obstetrics & Gynecology © 2018 ISUOG.

Cell-Free DNA Analysis in Maternal Blood: Differences in Estimates between Laboratories with Different Methodologies Using a Propensity Score Approach

OBJECTIVES

To evaluate the failure rate and performance of cell-free DNA (cfDNA) testing, mainly in terms of detection rates for trisomy 21, performed by 2 laboratories using different analytical methods.

METHODS

cfDNA testing was performed on 2,870 pregnancies with the HarmonyTM Prenatal Test using the targeted digital analysis of selected regions (DANSR) method, and on 2,635 pregnancies with the "Cerba test" using the genome-wide massively parallel sequencing (GW-MPS) method, with available outcomes. Propensity score analysis was used to match patients between the 2 groups. A comparison of the detection rates for trisomy 21 between the 2 laboratories was made.

RESULTS

In all, 2,811 patients in the Harmony group and 2,530 patients in the Cerba group had no trisomy 21, 18, or 13. Postmatched comparisons of the patient characteristics indicated a higher no-result rate in the Harmony group (1.30%) than in the Cerba group (0.75%; p = 0.039). All 41 cases of trisomy 21 in the Harmony group and 93 cases in the Cerba group were detected.

CONCLUSIONS

Both methods of cfDNA testing showed low no-result rates and a comparable performance in detecting trisomy 21; yet GW-MPS had a slightly lower no-result rate than the DANSR method.

ASPRE trial: incidence of preterm pre-eclampsia in patients fulfilling ACOG and NICE criteria according to risk by FMF algorithm

OBJECTIVE

To report the incidence of preterm pre-eclampsia (PE) in women who are screen positive according to the criteria of the National Institute for Health and Care Excellence (NICE) and the American College of Obstetricians and Gynecologists (ACOG), and compare the incidence with that in those who are screen positive or screen negative by The Fetal Medicine Foundation (FMF) algorithm.

METHODS

This was a secondary analysis of data from the ASPRE study. The study population consisted of women with singleton pregnancy who underwent prospective screening for preterm PE by means of the FMF algorithm, which combines maternal factors and biomarkers at 11-13 weeks' gestation. The incidence of preterm PE in women fulfilling the NICE and ACOG criteria was estimated; in these patients the incidence of preterm PE was then calculated in those who were screen negative relative to those who were screen positive by the FMF algorithm.

RESULTS

A total of 34 573 women with singleton pregnancy delivering at ≥ 24 weeks' gestation underwent prospective screening for preterm PE, of which 239 (0.7%) cases developed preterm PE. At least one of the ACOG criteria was fulfilled in 22 287 (64.5%) pregnancies and the incidence of preterm PE was 0.97% (95% CI, 0.85-1.11%); in the subgroup that was screen positive by the FMF algorithm the incidence of preterm PE was 4.80% (95% CI, 4.14-5.55%), and in those that were screen negative it was 0.25% (95% CI, 0.18-0.33%), with a relative incidence in FMF screen negative to FMF screen positive of 0.051 (95% CI, 0.037-0.071). In 1392 (4.0%) pregnancies, at least one of the NICE high-risk criteria was fulfilled, and in this group the incidence of preterm PE was 5.17% (95% CI, 4.13-6.46%); in the subgroups of screen positive and screen negative by the FMF algorithm, the incidence of preterm PE was 8.71% (95% CI, 6.93-10.89%) and 0.65% (95% CI, 0.25-1.67%), respectively, and the relative incidence was 0.075 (95% CI, 0.028-0.205). In 2360 (6.8%) pregnancies fulfilling at least two of the NICE moderate-risk criteria, the incidence of preterm PE was 1.74% (95% CI, 1.28-2.35%); in the subgroups of screen positive and screen negative by the FMF algorithm the incidence was 4.91% (95% CI, 3.54-6.79%) and 0.42% (95% CI, 0.20-0.86%), respectively, and the relative incidence was 0.085 (95% CI, 0.038-0.192).

CONCLUSION

In women who are screen positive for preterm PE by the ACOG or NICE criteria but screen negative by the FMF algorithm, the risk of preterm PE is reduced to within or below background levels. The results provide further evidence to support the personalized risk-based screening method that combines maternal factors and biomarkers. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Aspirin for Evidence-Based Preeclampsia Prevention trial: effect of aspirin on length of stay in the neonatal intensive care unit

BACKGROUND

Preeclampsia is a major pregnancy complication with adverse short- and long-term implications for both the mother and baby. Screening for preeclampsia at 11-13 weeks' gestation by a combination of maternal demographic characteristics and medical history with measurements of biomarkers can identify about 75% of women who develop preterm preeclampsia with delivery at <37 weeks' gestation and 90% of those with early preeclampsia at <32 weeks, at a screen-positive rate of 10%. A recent trial (Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-Based Preeclampsia Prevention) has reported that in women identified by first-trimester screening as being at high risk for preeclampsia, use of aspirin (150 mg/d from the first to the third trimester), compared to placebo, reduced the incidence of preterm preeclampsia, which was the primary outcome, by 62% (95% confidence interval, 26-80%) and the incidence of early preeclampsia by 89% (95% confidence interval, 53-97%). The surprising finding of the trial was that despite the reduction in preeclampsia the incidence of admission to the neonatal intensive care unit, which was one of the secondary outcomes, was not significantly affected (odds ratio, 0.93; 95% confidence interval, 0.62-1.40).

OBJECTIVE

We sought to examine the effect of prophylactic use of aspirin during pregnancy in women at high risk of preeclampsia on length of stay in the neonatal intensive care unit.

STUDY DESIGN

This was a secondary analysis of data from the Aspirin for Evidence-Based Preeclampsia Prevention trial to assess evidence of differences in the effect of aspirin on length of stay in neonatal intensive care. Bootstrapping was used for the comparison of mean length of stay between the aspirin and placebo groups. Logistic regression was used to assess treatment effects on stay in the neonatal intensive care unit.

RESULTS

In the trial there were 1620 participants and 1571 neonates were liveborn. The total length of stay in neonatal intensive care was substantially longer in the placebo than aspirin group (1696 vs 531 days). This is a reflection of significantly shorter mean lengths of stay in babies admitted to the neonatal intensive care unit from the aspirin than the placebo group (11.1 vs 31.4 days), a reduction of 20.3 days (95% confidence interval, 7.0-38.6; P = .008). Neonatal intensive care of babies born at <32 weeks' gestation contributed 1856 (83.3%) of the total of 2227 days in intensive care across both treatment arms. These occurred in 9 (1.2%) of the 777 livebirths in the aspirin group and in 23 (2.9%) of 794 in the placebo group (odds ratio, 0.42; 95% confidence interval, 0.19-0.93; P = .033). Overall, in the whole population, including 0 lengths of stay for those not admitted to the neonatal intensive care unit, the mean length of stay was longer in the placebo than aspirin group (2.06 vs 0.66 days; reduction of 1.4 days; 95% confidence interval, 0.45-2.81; P = .014). This corresponds to a reduction in length of stay of 68% (95% confidence interval, 20-86%).

CONCLUSION

In pregnancies at high risk of preeclampsia administration of aspirin reduces the length of stay in the neonatal intensive care unit by about 70%. This reduction could essentially be attributed to a decrease in the rate of births at <32 weeks' gestation, mainly because of prevention of early preeclampsia. The findings have implications for both short- and long-term health care costs as well as infant survival and handicap.

Comparison of conventional 2D ultrasound to magnetic resonance imaging for prenatal estimation of birthweight in twin pregnancy

BACKGROUND

During prenatal follow-up of twin pregnancies, accurate identification of birthweight and birthweight discordance is important to identify the high-risk group and plan perinatal care. Unfortunately, prenatal evaluation of birthweight discordance by 2-dimensional ultrasound has been far from optimal.

OBJECTIVE

The objective of the study was to prospectively compare estimates of fetal weight based on 2-dimensional ultrasound (ultrasound-estimated fetal weight) and magnetic resonance imaging (magnetic resonance-estimated fetal weight) with actual birthweight in women carrying twin pregnancies.

STUDY DESIGN

Written informed consent was obtained for this ethics committee-approved study. Between September 2011 and December 2015 and within 48 hours before delivery, ultrasound-estimated fetal weight and magnetic resonance-estimated fetal weight were conducted in 66 fetuses deriving from twin pregnancies at 34.3-39.0 weeks; gestation. Magnetic resonance-estimated fetal weight derived from manual measurement of fetal body volume. Comparison of magnetic resonance-estimated fetal weight and ultrasound-estimated fetal weight measurements vs birthweight was performed by calculating parameters as described by Bland and Altman. Receiver-operating characteristic curves were constructed for the prediction of small-for-gestational-age neonates using magnetic resonance-estimated fetal weight and ultrasound-estimated fetal weight. For twins 1 and 2 separately, the relative error or percentage error was calculated as follows: (birthweight - ultrasound-estimated fetal weight (or magnetic resonance-estimated fetal weight)/birthweight) × 100 (percentage). Furthermore, ultrasound-estimated fetal weight, magnetic resonance-estimated fetal weight, and birthweight discordance were calculated as 100 × (larger estimated fetal weight-smaller estimated fetal weight)/larger estimated fetal weight. The ultrasound-estimated fetal weight discordance and the birthweight discordance were correlated using linear regression analysis and Pearson's correlation coefficient. The same was done between the magnetic resonance-estimated fetal weight and birthweight discordance. To compare data, the χ², McNemar test, Student t test, and Wilcoxon signed rank test were used as appropriate. We used the Fisher r-to-z transformation to compare correlation coefficients.

RESULTS

The bias and the 95% limits of agreement of ultrasound-estimated fetal weight are 2.99 (-19.17% to 25.15%) and magnetic resonance-estimated fetal weight 0.63 (-9.41% to 10.67%). Limits of agreement were better between magnetic resonance-estimated fetal weight and actual birthweight as compared with the ultrasound-estimated fetal weight. Of the 66 newborns, 27 (40.9%) were of weight of the 10th centile or less and 21 (31.8%) of the fifth centile or less. The area under the receiver-operating characteristic curve for prediction of birthweight the 10th centile or less by prenatal ultrasound was 0.895 (P < .001; SE, 0.049), and by magnetic resonance imaging it was 0.946 (P < .001; SE, 0.024). Pairwise comparison of receiver-operating characteristic curves showed a significant difference between the areas under the receiver-operating characteristic curves (difference, 0.087, P = .049; SE, 0.044). The relative error for ultrasound-estimated fetal weight was 6.8% and by magnetic resonance-estimated fetal weight, 3.2% (P < .001). When using ultrasound-estimated fetal weight, 37.9% of fetuses (25 of 66) were estimated outside the range of ±10% of the actual birthweight, whereas this dropped to 6.1% (4 of 66) with magnetic resonance-estimated fetal weight (P < .001). The ultrasound-estimated fetal weight discordance and the birthweight discordance correlated significantly following the linear equation: ultrasound-estimated fetal weight discordance = 0.03 + 0.91 × birthweight (r = 0.75; P < .001); however, the correlation was better with magnetic resonance imaging: magnetic resonance-estimated fetal weight discordance = 0.02 + 0.81 × birthweight (r = 0.87; P < .001).

CONCLUSION

In twin pregnancies, magnetic resonance-estimated fetal weight performed immediately prior to delivery is more accurate and predicts small-for-gestational-age neonates significantly better than ultrasound-estimated fetal weight. Prediction of birthweight discordance is better with magnetic resonance imaging as compared with ultrasound.

How Does Imaging of Congenital Zika Compare with Imaging of Other TORCH Infections?

The acronym TORCH is used to refer to congenital infections, such as toxoplasmosis, other infections (such as syphillis, varicella-zoster, and parvovirus B19), cytomegalovirus, and herpes simplex virus. The classic findings in patients with TORCH infections include rash in the mother during pregnancy and ocular findings in the newborn. Zika virus has emerged as an important worldwide congenital infection. It fits well with other congenital TORCH infections since there is a rash in the mother and there are commonly ocular abnormalities in the newborn. TORCH infections are recognized to have neurologic effects, such as ventriculomegaly, intraventricular adhesions, subependymal cysts, intracerebral calcifications, and microcephaly; however, the Zika virus is intensely neurotropic. Thus, it targets neural progenitor cells, leading to a more severe spectrum of central nervous system abnormalities than is typically seen in other TORCH infections, while relatively sparing the other organ systems. In this review, nonspecific findings of congenital infections initially will be described, then individual TORCH infections will be described and compared with the imaging findings associated with congenital Zika virus infection. For the radiologist, awareness of imaging features of common congenital infections may facilitate early diagnosis and may, at times, lead to prompt initiation of therapy. Online supplemental material is available for this article.

Prenatal Screening for 22q11.2 Deletion Using a Targeted Microarray-Based Cell-Free DNA Test

OBJECTIVE

To determine the performance of a targeted microarray-based cell-free DNA (cfDNA) test (Harmony Prenatal Test®) for the identification of pregnancies at increased risk for 22q11.2 deletion.

METHODS

Test performance was determined in 2 steps including a total of 1,953 plasma samples. Analytical validation was performed in 1,736 plasma samples. Clinical verification of performance was performed in an additional 217 prospectively ascertained samples from pregnancies with fetal deletion status determined by diagnostic testing.

RESULTS

Analytical sensitivity was 75.4% (95% CI: 67.1-82.2%) based on 122 samples with deletions ranging from 1.96 to 3.25 Mb. In 1,614 presumed unaffected samples, specificity was determined to be at least 99.5% (95% CI: 99.0-99.7%). In the clinical cohort, 5 of 7 samples from pregnancies affected with 22q11.2 deletion were determined to have a high probability of deletion. There were no false positive results in the 210 unaffected samples in this cohort. These clinical data are consistent with the performance demonstrated in the analytical validation.

CONCLUSIONS

cfDNA testing using a targeted microarray-based technology is able to identify pregnancies at increased risk for 22q11.2 deletions of 3.0 Mb and smaller while maintaining a low false positive rate.

Aspirin for Evidence-Based Preeclampsia Prevention trial: effect of aspirin in prevention of preterm preeclampsia in subgroups of women according to their characteristics and medical and obstetrical history

BACKGROUND

The Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-Based Preeclampsia Prevention trial demonstrated that in women who were at high risk for preterm preeclampsia with delivery at <37 weeks' gestation identified by screening by means of an algorithm that combines maternal factors and biomarkers at 11-13 weeks' gestation, aspirin administration from 11 to 14 until 36 weeks' gestation was associated with a significant reduction in the incidence of preterm preeclampsia (odds ratio 0.38; 95% confidence interval, 0.20 to 0.74; P=0.004).

OBJECTIVE

We sought to examine whether there are differences in the effect of aspirin on the incidence of preterm preeclampsia in the Aspirin for Evidence-Based Preeclampsia Prevention trial in subgroups defined according to maternal characteristics and medical and obstetrical history.

STUDY DESIGN

This was a secondary analysis of data from the Aspirin for Evidence-Based Preeclampsia Prevention trial. Subgroup analysis was performed to assess evidence of differences in the effect of aspirin on incidence of preterm preeclampsia in subgroups defined by maternal age (<30 and ≥30 years), body mass index (<25 and ≥25 kg/m²), racial origin (Afro-Caribbean, Caucasian and other), method of conception (natural and assisted), cigarette smoking (smoker and non-smoker), family history of preterm preeclampsia (present and absent), obstetrical history (nulliparous, multiparous with previous preterm preeclampsia and multiparous without previous preterm preeclampsia), history of chronic hypertension (present and absent). Interaction tests were performed on the full data set of patients in the intention to treat population and on the data set of patients who took ≥ 90% of the prescribed medication. Results are presented as forest plot with P values for the interaction effects, group sizes, event counts and estimated odds ratios. We examined whether the test of interaction was significant at the 5% level with a Bonferroni adjustment for multiple comparisons.

RESULTS

There was no evidence of heterogeneity in the aspirin effect in subgroups defined according to maternal characteristics and obstetrical history. In participants with chronic hypertension preterm preeclampsia occurred in 10.2% (5/49) in the aspirin group and 8.2% (5/61) in the placebo group (adjusted odds ratio, 1.29; 95% confidence interval, 0.33-5.12). The respective values in those without chronic hypertension were 1.1% (8/749) in the aspirin group and 3.9% (30/761) in the placebo group (adjusted odds ratio, 0.27; 95% confidence interval, 0.12-0.60). In all participants with adherence of ≥90% the adjusted odds ratio in the aspirin group was 0.24 (95% confidence interval, 0.09-0.65); in the subgroup with chronic hypertension it was 2.06 (95% confidence interval, 0.40-10.71); and in those without chronic hypertension it was 0.05 (95% confidence interval, 0.01-0.41). For the complete data set the test of interaction was not significant at the 5% level (P = .055), but in those with adherence ≥90%, after adjustment for multiple comparisons, the interaction was significant at the 5% level (P = .0019).

CONCLUSION

The beneficial effect of aspirin in the prevention of preterm preeclampsia may not apply in pregnancies with chronic hypertension. There was no evidence of heterogeneity in the aspirin effect in subgroups defined according to maternal characteristics and obstetrical history.

ASPRE trial: performance of screening for preterm pre-eclampsia

OBJECTIVE

To examine the performance of screening for preterm and term pre-eclampsia (PE) in the study population participating in the ASPRE (Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-Based Preeclampsia Prevention) trial.

METHODS

This was a prospective first-trimester multicenter study on screening for preterm PE in 26 941 singleton pregnancies by means of an algorithm that combines maternal factors, mean arterial pressure, uterine artery pulsatility index and maternal serum pregnancy-associated plasma protein-A and placental growth factor at 11-13 weeks' gestation. Eligible women with an estimated risk for preterm PE of > 1 in 100 were invited to participate in a double-blind trial of aspirin (150 mg per day) vs placebo from 11-14 until 36 weeks' gestation, which showed that, in the aspirin group, the incidence of preterm PE was reduced by 62%. In the screened population, the detection rates (DRs) and false-positive rates (FPRs) for delivery with PE < 37 and ≥ 37 weeks were estimated after adjustment for the effect of aspirin in those receiving this treatment. We excluded 1144 (4.2%) pregnancies because of loss to follow-up or study withdrawal (n = 716), miscarriage (n = 243) or termination (n = 185).

RESULTS

The study population of 25 797 pregnancies included 180 (0.7%) cases of preterm PE, 450 (1.7%) of term PE and 25 167 (97.6%) without PE. In combined first-trimester screening for preterm PE with a risk cut-off of 1 in 100, the DR was 76.7% (138/180) for preterm PE and 43.1% (194/450) for term PE, at screen-positive rate of 10.5% (2707/25 797) and FPR of 9.2% (2375/25 797).

CONCLUSION

The performance of screening in the ASPRE study was comparable with that of a study of approximately 60 000 singleton pregnancies used for development of the algorithm; in that study, combined screening detected 76.6% of cases of preterm PE and 38.3% of term PE at a FPR of 10%. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Screening for Sex Chromosome Aneuploidy by Cell-Free DNA Testing: Patient Choice and Performance

OBJECTIVE

To study patient choice regarding testing for sex chromosome aneuploidy (SCA) and the performance of cell-free DNA (cfDNA) screening for SCA.

METHODS

Patient choice regarding screening for SCA and factors influencing this choice were evaluated in a single center. In a subsequent two-center study, cases that screened positive for SCA were analyzed to determine the positive predictive value (PPV) for each SCA.

RESULTS

In all, 1,957 (61.9%) of the 3,162 patients undergoing cfDNA testing opted for SCA screening. Regression analysis demonstrated that independent predictors of a patient's decision for SCA were earlier gestational age, spontaneous conception, and cfDNA chosen as a primary method of screening. A total of 161 cases screened positive for SCA and follow-up data were available for 118 (73.3%). Forty-six of the 61 cases of 45,X were false-positive results and 15 were concordant with the fetal karyotype (PPV = 24.6%). Seventeen of the 22 cases of 47,XXX were false positive and 5 concordant (PPV = 22.7%). Eleven of the 30 cases of 47,XXY were false positive and 19 concordant (PPV = 63.3%). All 5 cases of 47,XYY were correctly identified, thus yielding a PPV of 100%.

CONCLUSION

More than half of the patients undergoing cfDNA aneuploidy screening also opted for SCA testing, but they were less likely to do so in the presence of an increased risk of trisomy. SCAs involving the X chromosome had a lower PPV than those involving the Y chromosome.

Aspirin versus Placebo in Pregnancies at High Risk for Preterm Preeclampsia

BACKGROUND

Preterm preeclampsia is an important cause of maternal and perinatal death and complications. It is uncertain whether the intake of low-dose aspirin during pregnancy reduces the risk of preterm preeclampsia.

METHODS

In this multicenter, double-blind, placebo-controlled trial, we randomly assigned 1776 women with singleton pregnancies who were at high risk for preterm preeclampsia to receive aspirin, at a dose of 150 mg per day, or placebo from 11 to 14 weeks of gestation until 36 weeks of gestation. The primary outcome was delivery with preeclampsia before 37 weeks of gestation. The analysis was performed according to the intention-to-treat principle.

RESULTS

A total of 152 women withdrew consent during the trial, and 4 were lost to follow up, which left 798 participants in the aspirin group and 822 in the placebo group. Preterm preeclampsia occurred in 13 participants (1.6%) in the aspirin group, as compared with 35 (4.3%) in the placebo group (odds ratio in the aspirin group, 0.38; 95% confidence interval, 0.20 to 0.74; P=0.004). Results were materially unchanged in a sensitivity analysis that took into account participants who had withdrawn or were lost to follow-up. Adherence was good, with a reported intake of 85% or more of the required number of tablets in 79.9% of the participants. There were no significant between-group differences in the incidence of neonatal adverse outcomes or other adverse events.

CONCLUSIONS

Treatment with low-dose aspirin in women at high risk for preterm preeclampsia resulted in a lower incidence of this diagnosis than placebo. (Funded by the European Union Seventh Framework Program and the Fetal Medicine Foundation; EudraCT number, 2013-003778-29 ; Current Controlled Trials number, ISRCTN13633058 .).

First-Trimester Combined Multimarker Prospective Study for the Detection of Pregnancies at a High Risk of Developing Preeclampsia Using the Fetal Medicine Foundation-Algorithm

OBJECTIVE

To evaluate the Fetal Medicine Foundation (FMF) algorithm prospectively at 11-13 weeks' gestation in the prediction of preeclampsia (PE).

METHODS

Single-center prospective screening study for PE of singleton pregnancies at 11-13 weeks. The FMF algorithm takes into account maternal characteristics and biomarkers. Detection rate (DR) for a 10% false-positive rate (FPR) for delivery with preterm and term PE was estimated.

RESULTS

Between January 2011 and December 2013, of 3,239 patients available for final analysis, 36 (1.1%) subsequently developed preterm and 44 (1.4%) term PE. In combined screening by maternal factors, mean arterial pressure, uterine artery pulsatility index, and serum placental growth factor, the DR was 80.6% (95% CI 64.0-91.8) for PE at <37 weeks and 31.8% (95% CI 18.6-47.6) for PE at ≥37 weeks, at a 10% FPR.

CONCLUSION

Our data suggest that the FMF algorithm provides effective first-trimester screening for preterm PE.

Antenatal BAY 41-2272 reduces pulmonary hypertension in the rabbit model of congenital diaphragmatic hernia

Infants with congenital diaphragmatic hernia (CDH) fail to adapt at birth because of persistent pulmonary hypertension (PH), a condition characterized by excessive muscularization and abnormal vasoreactivity of pulmonary vessels. Activation of soluble guanylate cyclase by BAY 41-2272 prevents pulmonary vascular remodeling in neonatal rats with hypoxia-induced PH. By analogy, we hypothesized that prenatal administration of BAY 41-2272 would improve features of PH in the rabbit CDH model. Rabbit fetuses with surgically induced CDH at day 23 of gestation were randomized at day 28 for an intratracheal injection of BAY 41-2272 or vehicle. After term delivery (day 31), lung mechanics, right ventricular pressure, and serum NH2-terminal-pro-brain natriuretic peptide (NT-proBNP) levels were measured. After euthanasia, lungs were processed for biological or histological analyses. Compared with untouched fetuses, the surgical creation of CDH reduced the lung-to-body weight ratio, increased mean terminal bronchial density, and impaired lung mechanics. Typical characteristics of PH were found in the hypoplastic lungs, including increased right ventricular pressure, higher serum NT-proBNP levels, thickened adventitial and medial layers of pulmonary arteries, reduced capillary density, and lower levels of endothelial nitric oxide synthase. A single antenatal instillation of BAY 41-2272 reduced mean right ventricular pressure and medial thickness of small resistive arteries in CDH fetuses. Capillary density, endothelial cell proliferation, and transcripts of endothelial nitric oxide synthase increased, whereas airway morphometry, lung growth, and mechanics remained unchanged. These results suggest that pharmacological activation of soluble guanylate cyclase may provide a new approach to the prenatal treatment of PH associated with CDH.

Increased TGF-β: a drawback of tracheal occlusion in human and experimental congenital diaphragmatic hernia?

Survivors of severe congenital diaphragmatic hernia (CDH) present significant respiratory morbidity despite lung growth induced by fetal tracheal occlusion (TO). We hypothesized that the underlying mechanisms would involve changes in lung extracellular matrix and dysregulated transforming growth factor (TGF)-β pathway, a key player in lung development and repair. Pulmonary expression of TGF-β signaling components, downstream effectors, and extracellular matrix targets were evaluated in CDH neonates who died between birth and the first few weeks of life after prenatal conservative management or TO, and in rabbit pups that were prenatally randomized for surgical CDH and TO vs. sham operation. Before tissue harvesting, lung tissue mechanics in rabbits was measured using the constant-phase model during the first 30 min of life. Human CDH and control fetal lungs were also collected from midterm onwards. Human and experimental CDH did not affect TGF-β/Smad2/3 expression and activity. In human and rabbit CDH lungs, TO upregulated TGF-β transcripts. Analysis of downstream pathways indicated increased Rho-associated kinases to the detriment of Smad2/3 activation. After TO, subtle accumulation of collagen and α-smooth muscle actin within alveolar walls was detected in rabbit pups and human CDH lungs with short-term mechanical ventilation. Despite TO-induced lung growth, mediocre lung tissue mechanics in the rabbit model was associated with increased transcription of extracellular matrix components. These results suggest that prenatal TO increases TGF-β/Rho kinase pathway, myofibroblast differentiation, and matrix deposition in neonatal rabbit and human CDH lungs. Whether this might influence postnatal development of sustainably ventilated lungs remains to be determined.

Stomach position in prediction of survival in left-sided congenital diaphragmatic hernia with or without fetoscopic endoluminal tracheal occlusion

OBJECTIVE

To investigate the value of fetal stomach position in predicting postnatal outcome in left-sided congenital diaphragmatic hernia (CDH) with and without fetoscopic endoluminal tracheal occlusion (FETO).

METHODS

This was a retrospective review of CDH cases that were expectantly managed or treated with FETO, assessed from May 2008 to October 2013, in which we graded, on a scale of 1-4, stomach position on the four-chamber view of the heart with respect to thoracic structures. Logistic regression analysis was used to investigate the effect of management center (Paris, Brussels, Barcelona, Milan), stomach grading, observed-to-expected lung area-to-head circumference ratio (O/E-LHR), gestational age at delivery, birth weight in expectantly managed CDH, gestational ages at FETO and at removal and period of tracheal occlusion, on postnatal survival in CDH cases treated with FETO.

RESULTS

We identified 67 expectantly managed CDH cases and 47 CDH cases that were treated with FETO. In expectantly managed CDH, stomach position and O/E-LHR predicted postnatal survival independently. In CDH treated with FETO, stomach position and gestational age at delivery predicted postnatal survival independently.

CONCLUSION

In left-sided CDH with or without FETO, stomach position is predictive of postnatal survival.

Performance of screening for aneuploidies by cell-free DNA analysis of maternal blood in twin pregnancies

OBJECTIVES

To report clinical implementation of cell-free DNA (cfDNA) analysis of maternal blood in screening for trisomies 21, 18 and 13 in twin pregnancies and examine variables that could influence the failure rate of the test.

METHODS

cfDNA testing was performed in 515 twin pregnancies at 10-28 weeks' gestation. The failure rate of the test to provide results was compared with that in 1847 singleton pregnancies, and logistic regression analysis was used to determine which factors among maternal and pregnancy characteristics were significant predictors of test failure.

RESULTS

Failure rate of the cfDNA test at first sampling was 1.7% in singletons and 5.6% in twins. Of those with a test result, the median fetal fraction in twins was 8.7% (range, 4.1-30.0%), which was lower than that in singletons (11.7% (range, 4.0-38.9%)). Multivariable regression analysis demonstrated that twin pregnancy, higher maternal weight and conception by in-vitro fertilization provided significant independent prediction of test failure. Follow-up was available in 351 (68.2%) of the twin pregnancies and comprised 334 with euploid fetuses, 12 discordant for trisomy 21 and five discordant for trisomy 18. In all 323 euploid cases with a result, the risk score for each trisomy was < 1:10 000. In 11 of the 12 cases with trisomy 21 and in the five with trisomy 18, the cfDNA test gave a high-risk result, but in one case of trisomy 21, the score was < 1:10 000.

CONCLUSION

In twin pregnancies screening by cfDNA testing is feasible, but the failure rate is higher and detection rate may be lower than in singletons.

Parental acceptance of minimally invasive fetal and neonatal autopsy compared with conventional autopsy

OBJECTIVE

To determine parental acceptance of minimally invasive autopsy (MIA) involving postmortem imaging and organ tissue sampling compared with conventional autopsy and to compare the acceptability of percutaneous versus laparoscopic-guided biopsy.

METHODS

Following termination of pregnancy parents were offered the option of traditional autopsy and subsequently interviewed about their acceptance of MIA. The McNemar test for paired samples was used to assess the difference in acceptance of MIA and conventional autopsy. The Wilcoxon signed-rank test for paired samples was used to compare the acceptance score for percutaneous versus laparoscopic-guided biopsy. Logistic regression was selected to study the association of parental acceptance of conventional autopsy and MIA with different variables.

RESULTS

Conventional autopsy was accepted by 42 (60.0%) of the 70 parents. Regression analysis showed that non-Muslim faith was the only factor significantly associated with acceptance of conventional autopsy (p = 0.030). Of 28 parents who initially refused conventional autopsy, 13(46.4%) subsequently accepted MIA, increasing acceptance to 78.6% (p < 0.001). Regression analysis showed that none of the factors significantly affected MIA acceptance. Parents expressed no preference between postmortem percutaneous versus laparoscopic-guided biopsy (p = 0.061).

CONCLUSION

Post-mortem imaging combined with systematic organ biopsies is highly acceptable among all parents independent of their religion and the method used for organ biopsy.

Arabin cervical pessary in women at high risk of preterm birth: a magnetic resonance imaging observational follow-up study

OBJECTIVE

To help elucidate the mechanism of action of the Arabin cervical pessary in pregnancies at high risk for preterm delivery.

METHODS

Cervical length and uterocervical angle were evaluated in relation to gestational age in 198 pregnancies not at high risk for preterm birth that underwent clinical fetal magnetic resonance imaging (MRI). Additionally, in 73 singleton pregnancies at high risk for preterm birth, an Arabin cervical pessary was placed at 14-33 weeks' gestation. We performed MRI of the cervix immediately before and after placement and at monthly follow-up until removal of the pessary. In a subgroup of 54 pregnancies with a short cervix and pessary placement at 17-31 weeks' gestation, the uterocervical angle and cervical length at follow-up were compared with the preplacement values.

RESULTS

In pregnancies not at high risk for preterm birth, the uterocervical angle did not vary, but cervical length showed a significant decrease with gestational age (r = -0.15, P < 0.05). Among the high-risk patients, the cervical pessary was successfully placed at first attempt in 60 (82.2%) and by the second attempt in 66 (90.4%), remaining well positioned until removal. In five patients we failed to place the pessary after two attempts, in one patient the pessary dislodged during follow-up and in one case the pessary was partly placed in the external cervical canal and triggered labor the next day. Among the subgroup of 54 patients, the median uterocervical angle immediately after pessary placement was significantly more acute than that prior to placement in the 46 (85.2%) who delivered after 34 weeks (132° vs 146°, P < 0.01), but was unchanged in the eight patients who delivered before 34 weeks (143° vs 152°, P > 0.05).

CONCLUSION

In patients at high risk for preterm delivery, correct placement of the Arabin cervical pessary should be checked immediately; this can be performed quickly and easily using MRI. This study provides some evidence that, in singleton pregnancies with a short cervix, a cervical pessary delays birth through a mechanical effect on the uterocervical angle.

Alveolarization genes modulated by fetal tracheal occlusion in the rabbit model for congenital diaphragmatic hernia: a randomized study

Background

The mechanisms by which tracheal occlusion (TO) improves alveolarization in congenital diaphragmatic hernia (CDH) are incompletely understood. Therefore transcriptional and histological effects of TO on alveolarization were studied in the rabbit model for CDH. The question of the best normalization strategy for gene expression analysis was also addressed.

Methods

Fetal rabbits were randomized for CDH or sham operation on gestational day 23/31 and for TO or sham operation on day 28/31 resulting in four study groups. Untouched littermates were added. At term and before lung harvest, fetuses were subjected to mechanical ventilation or not. Quantitative real-time PCR was performed on lungs from 4–5 fetuses of each group with and without previous ventilation. Stability of ten housekeeping genes (HKGs) and optimal number of HKGs for normalization were determined, followed by assessment of HKG expression levels. Expression levels of eleven target genes were studied in ventilated lungs, including genes regulating elastogenesis, cell-environment interactions, and thinning of alveolar walls. Elastic staining, immunohistochemistry and Western blotting completed gene analysis.

Results

Regarding HKG expression, TO increased β-actin and β-subunit of ATP synthase. Mechanical ventilation increased β-actin and β2-microglobulin. Flavoprotein subunit of succinate dehydrogenase and DNA topoisomerase were the most stable HKGs. CDH lungs showed disorganized elastin deposition with lower levels for tropoelastin, fibulin-5, tenascin-C, and α6-integrin. After TO, CDH lungs displayed a normal pattern of elastin distribution with increased levels for tropoelastin, fibulin-5, tenascin-C, α6-integrin, ß1-integrin, lysyl oxidase, and drebrin. TO increased transcription and immunoreactivity of tissue inhibitor of metalloproteinase-1.

Conclusions

Experimental TO might improve alveolarization through the mechanoregulation of crucial genes for late lung development. However part of the transcriptional changes involved genes that were not affected in CDH, raising the question of TO-induced disturbances of alveolar remodeling. Attention should also be paid to selection of HKGs for studies on mechanotransduction-mediated gene expressions.

Fetal weight estimation: comparison of two-dimensional US and MR imaging assessments

PURPOSE

To prospectively define fetal density in the second half of pregnancy by using magnetic resonance (MR) imaging and to compare estimates of fetal weight based on ultrasonography (US) and MR imaging with actual birth weight.

MATERIALS AND METHODS

Written informed consent was obtained for this ethics committee-approved study. In this cross-sectional study between March 2011 and May 2012, fetal density was calculated as actual birth weight at delivery divided by fetal body volume at MR imaging in 188 fetuses between 20 weeks and 2 days and 42 weeks and 1 day of gestational age. Regression analysis was used to investigate the effect of variables, including sex, on fetal density. The US estimate of fetal weight was performed according to Hadlock et al, and the MR estimate of fetal weight was calculated based on the equation developed by Baker et al. US and MR estimates of fetal weight were compared with actual birth weights by using regression analysis.

RESULTS

Median fetal density was equal to 1.04 (range, 0.95-1.18). Fetal density was significantly associated with gestational age at delivery but not with fetal sex. In 26.6% of fetuses, the US estimate of fetal weight had a relative error of more than 10%, while a similar relative error for the MR estimate of fetal weight occurred in only 1.1% of fetuses. The limits of agreement were narrower with the MR estimate of fetal weight compared with the US estimate of fetal weight.

CONCLUSION

In the second half of pregnancy, fetal density varies with gestational age. Fetal weight estimates by using fetal MR imaging are better than those by using prenatal US.

Signaling molecules in the fetal rabbit model for congenital diaphragmatic hernia

RATIONALE AND OBJECTIVES

Little is known about molecular changes in lungs of fetal rabbits with surgically induced diaphragmatic hernia (DH). Therefore, we examined in this model gene expressions of pivotal molecules for the developing lung.

METHODS

At day 23 of gestation, DH was created in 12 fetuses from 4 does. Both lungs from six live DH fetuses and from six unoperated controls were harvested and weighed at term. Transcription of 15 genes involved in alveolarization, angiogenesis, regulation of vascular tone, or epithelial maturation was investigated by real-time quantitative polymerase chain reaction.

MAIN RESULTS

DH decreased lung-to-body weight ratio (P < 0.001). A bilateral downregulation was seen for genes encoding for tropoelastin (P < 0.01), lysyl oxidase (P < 0.05), fibulin 5 (P < 0.05), and cGMP specific phosphodiesterase 5 (P < 0.05). Lower mRNA levels for endothelial nitric oxide synthase occurred in the ipsilateral lung (P < 0.05).

CONCLUSIONS

Experimental DH in fetal rabbits disrupted transcription of genes implicated in lung growth and function. Similarities with the human disease make this model appropriate for investigation of new prenatal therapies.

First trimester fetal echocardiography: where are we now?

The detailed study of the fetal cardiac anatomy in the first trimester of pregnancy by means of ultrasound is feasible whether using a transvaginal or a transabdominal approach. There is nowadays enough evidence that ultrasound in the first trimester of pregnancy is a safe procedure provided thermal and mechanical indices are taken into account. The best timing for successful imaging of the four chambers and great arteries in early gestation appears to be between around 13 to 14 weeks rather than 11 to 12 weeks. In experienced hands, first-trimester fetal echocardiography is quite sensitive for the detection of major structural cardiac abnormalities. Besides the nasal bone, markers for first trimester screening of chromosomal abnormalities such as nuchal translucency thickness, the flow in the ductus venosus and the flow through the tricuspid valve constitute also markers for cardiac abnormalities. The finding of an increased nuchal translucency, an abnormal flow in the ductus venosus or a tricuspid regurgitation constitutes an indication for more detailed fetal cardiac assessment. Other indication for a detailed cardiac assessment is the finding of an aberrant right subclavian artery and vascular anomalies. The emerging importance of these markers has caused renewed interest in the early study of the fetal heart.

Antenatal ultrasound prediction of pulmonary hypoplasia in congenital diaphragmatic hernia: correlation with pathology

OBJECTIVE

To examine the relationship between observed to expected (o/e) lung to head circumference ratio (LHR) and lung-to-body weight ratio (LBWR) in fetuses with congenital diaphragmatic hernia (CDH).

METHODS

All consecutive fetuses with CDH and termination of pregnancy for which a postmortem examination was available, examined at three institutions between 2000 and 2010, were included in the study. Contralateral fetal lung area was measured by two-dimensional ultrasonography using the longest axis method and the o/e-LHR was calculated based on the appropriate normal mean for gestational age (GA). Regression analysis was used to determine the significance of association between the LBWR and the o/e-LHR for left and right-sided cases, and subsequently the predicted LBWR in left-sided CDH was calculated using the regression equation. Regression analysis was used to investigate the effect on the proportional difference between the predicted and observed LBWR of GA at o/e-LHR, time gap between o/e-LHR and LBWR measurement, proportional weight of the ipsilateral compared with total lung weight, presence of associated anomalies and intrathoracic herniation of the liver.

RESULTS

There were 23 fetuses with left-sided and seven fetuses with right-sided CDH. In left-sided CDH, the LBWR and the o/e-LHR correlated significantly, following the linear equation: LBWR = 0.0043 + (0.0134 × o/e-LHR) (r = 0.52, P = 0.012), but this was not the case for right-sided CDH, for which LBWR followed the equation: LBWR = 0.0107 - (0.0014 × o/e-LHR) (r = 0.08, P = 0.862), where o/e-LHR is expressed as percentage. Regression analysis showed that the proportional difference between predicted and observed LBWR in left-sided CDH was significantly and independently associated with GA at o/e-LHR measurement and proportional weight of ipsilateral vs. total lung weight.

CONCLUSION

In left-sided CDH, o/e-LHR correlates well with LBWR irrespective of the length of time between o/e-LHR and LBWR measurement, presence of associated anomalies and intrathoracic herniation of the liver. Inconsistencies between the two measurements are mainly attributable to the contribution of the ipsilateral lung to the total lung weight. In right-sided CDH, o/e-LHR does not correlate with LBWR.

Morphologic changes and methodological issues in the rabbit experimental model for diaphragmatic hernia

Fetal lung development may be impaired by some congenital anomalies or in utero events. Animal models are used to understand the pathophysiology of these diseases and explore therapeutic strategies. Our group has an interest in the prenatal management of congenital diaphragmatic hernia (CDH). Isolated CDH remains associated with a 30% mortality because of lung hypoplasia and pulmonary hypertension. On day 23 of gestation (pseudoglandular stage) CDH was created in both ovarian-end fetuses (n= 28) in 14 time-mated pregnant white rabbits (hybrid of Dendermonde and New-Zealand White). At term (day 30) all survived operated fetuses and size-matched controls were harvested. Fetuses/lungs were assigned randomly to formalin fixation either under pressure of 25 cm H2O (CDH25 n=5; CTR25 n=5) or without (0 cm H2O (CDH0 n=7; CTR0 n=7). Fetuses and lungs were first weighed, and then the lungs were processed for morphometry. Pulmonary development was evaluated by lung-to-body weight ratio (LBWR) and airway and vascular morphometry. Surgical induction of CDH does reduce the LBWR to hypoplastic levels. The contralateral lung weight is 81% of what is expected, whereas the ipsilateral lung is only 46% of the normal. This was accompagnied by a loss of conducting airway generations, precisely, terminal bronchioles (TB), which were surrounded by less alveoli. The ipsilateral CDH lung demonstrated a thickened media in the peripheral arteries as well. As a result, in the severely hypoplastic ipsilateral lung, an airway fixation pressure of 25 H2O has no significant effect on the morphometric indices. The contralateral lung has a normal amount of alveoli around a single TB, which also behave like alveoli of the normal lung, i.e. expand under pressure fixation. The present study on severely hypoplastic lungs that never respirated, shows that in contrast to normal lungs, the morphometric indices are not significantly influenced by a difference in fixation pressure. Increasing fixation pressure seems to expand the lung only when sufficient alveolated parenchyma is present.