Current controversies in prenatal diagnosis 2: are we ready to screen for fetal anomalies with first trimester ultrasound?

[Ultrasound screening for birth defects: A medico-economic review]

OBJECTIVES

The systematic use of ultrasound during pregnancy aims at birth defect detection. Our objective was to assess the economic efficiency of prenatal ultrasound screening for fetal malformations.

METHODS

We carried out a literature review on Medline via PubMed between 1985 and 2015, from the economic perspective of the prenatal ultrasound screening for fetal malformations.

RESULTS

The literature on this subject was sparse and we selected only twelve articles presenting relevant economic data, of which only eight were proper medico-economic studies. We found arguments for the economic effectiveness of ultrasound screening for fetal malformation detection, which is largely linked to the terminations of pregnancies and to the cost of the handicaps "avoided". However, none of the reviewed articles could reach medico-economic conclusions. Additionally, we highlighted various elements making economic analyses more complex in this field: the choice of the method, the uncertainty around two essential parameters (the efficiency of ultrasound and the costs of procedures) and the difficulties to compare or to generalize results. We also noticed important methodological heterogeneity among the studies and the absence of French study.

CONCLUSIONS

Previously published data are insufficient to assess the economic efficiency of prenatal ultrasound screening for fetal malformations.

The Performance of First-Trimester Anatomy Scan: A Decision Analysis

Introduction First-trimester ultrasound (US) for anatomy assessment may improve anomaly detection, but it may also increase overall US utilization. We sought to assess the utility of first-trimester US for evaluation of fetal anatomy. Materials and Methods A decision analytic model was created to compare first- plus second-trimester anatomy scans to second-trimester scan alone in four populations: general, normal weight women, obese women, and diabetics. Probability estimates were obtained from the literature. Outcomes considered were number of: major structural anomalies detected, US performed, and false-positive US. Multivariable sensitivity analyses were performed to evaluate the consistency of the model with varying assumptions. Results A strategy of first- plus second-trimester US detected the highest number of anomalies but required more US examinations per anomaly detected. The addition of a first-trimester anatomy US was associated with a small increase in the false-positive US (< 10/10,000). In populations with higher anomaly prevalence and lower second-trimester US sensitivity (i.e., diabetes, obesity), the number of additional US performed per anomaly detected with the first-trimester US was < 60. Discussion In high-risk populations, a first-trimester US in addition to a second-trimester US may be a beneficial approach to detecting anomalies.

Fetal Kidneys Ultrasound Appearance in the First Trimester - Clinical Significance and Limits of Counseling

OBJECTIVE

The objective of this study was to determine the visualizing rate of fetal kidneys at various gestational ages in late first trimester (FT) and to establish the clinical significance of their two-dimensional ultrasound (2DUS) appearance in the FT.

METHODS

In a prospective cross-sectional study, 1456 women from an unselected population underwent a detailed assessment of fetal anatomy at 11+0 -13+4 weeks of gestation with the use of transabdominal sonography. Information on the ultrasound findings, antenatal course and perinatal outcome was obtained in 1331 cases.

RESULTS

44 cases in which a congenital kidney disease was detected by ultrasound in the prenatal period were identified. The renal pathology was suspected in the FT in 8 cases, and confirmed by a standard test (postmortem autopsy or second-trimester scan) in 4 cases. The standard detailed second-trimester scan at 18-22 weeks diagnosed another 23 cases but refuted suspicion in 4 FT positive cases. The third trimester added another 17, all confirmed by the postpartum scan. For FT presence or absence of congenital renal anomalies, sensitivity, specificity, +LRs and -LRs of 2DUS were 9.09%, 99.69%, 29.25, and 0.91.

CONCLUSION

FT prenatal kidneys' visualization is critically dependent on the gestational age. FT diagnosis holds uncertainty. An early diagnosis carries a risk of providing a false-positive or a false-negative result, because the differentiation of the renal system is delayed or the diagnosis is not amenable yet to prenatal ultrasound. No FT findings can exclude the mid-trimester follow-up ultrasound scan. Second and third trimester scan are relevant for congenital kidney diseases.

2014 First-trimester ultrasound forum from the Korean Society of Ultrasound in Obstetrics and Gynecology

A first-trimester ultrasound scan has become an essential part of antenatal care. The Korean Society of Ultrasound in Obstetrics and Gynecology held a first-trimester ultrasound forum on April 5, 2014. The forum aimed to present an updated review of the literature on the topic of first-trimester ultrasound in specific lectures and to host a panel discussion on several important issues regarding first-trimester scans. The forum provided evidence- and consensus-based best practice patterns for obstetricians in Korea. Here, we report the review and checklists presented from the forum.

Fetal diagnostic indications for second and third trimester outpatient pregnancy termination

OBJECTIVE

To determine the frequency of diagnostic indications among women seeking to terminate pregnancies for reasons of fetal abnormality, spontaneous fetal demise, or a genetic disorder in a private outpatient clinic specializing in late outpatient abortion procedures.

METHOD

A total of 1005 women requested termination of pregnancy for reasons of genetic disorder, fetal anomaly, or fetal demise over 20 years (1992-2012). Gestational ages ranged from 12 to 39 weeks. In all cases, a documented diagnosis of fetal abnormality or fetal demise was made prior to referral. Records were reviewed to verify fetal diagnosis for all patients seeking termination of pregnancy for reasons of fetal disorder. Major complications included major unintended surgery, hemorrhage requiring transfusion, or pelvic infection.

RESULTS

Preoperative diagnoses included the following: chromosomal abnormalities (n = 378), genetic syndromes and single gene disorders (n = 30), structural anomalies (n = 494), and other conditions (n = 103). These include 26 cases of spontaneous fetal demise and nine selective terminations of one abnormal twin. The major complication rate was 0.5%.

CONCLUSIONS

The majority of diagnoses were in the categories of genetic disorder and neurologic abnormality.