Fetal transabdominal anatomy scanning using standard views at 11 to 14 weeks' gestation

Fetal Therapy for Renal Anhydramnios

The most severe forms of congenital anomalies of the kidney and urinary tract present in fetal life with early pregnancy renal anhydramnios and are considered lethal due to pulmonary hypoplasia without fetal therapy. Due to the high rate of additional structural anomalies, genetic abnormalities, and associated syndromes, detailed anatomic survey and genetic testing are imperative when stratifying which pregnancies are appropriate for fetal intervention. Restoring amniotic fluid around the fetus is the principal goal of prenatal treatment. The ongoing multi-center Renal Anhydramnios Fetal Therapy (RAFT) trial is assessing the safety and efficacy of serial amnioinfusions to prevent pulmonary hypoplasia so that the underlying renal disease can be addressed.

First trimester examination of fetal anatomy: clinical practice guideline by the World Association of Perinatal Medicine (WAPM) and the Perinatal Medicine Foundation (PMF)

This recommendation document follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation. We aim to bring together groups and individuals throughout the world for precise standardization to implement the ultrasound evaluation of the fetus in the first trimester of pregnancy and improve the early detection of anomalies and the clinical management of the pregnancy. The aim is to present a document that includes statements and recommendations on the standard evaluation of the fetal anatomy in the first trimester, based on quality evidence in the peer-reviewed literature as well as the experience of perinatal experts around the world.

Feasibility and learning curve of performing first trimester fetal anatomy screening among operators with varying experience using the protocol of the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG)

OBJECTIVE

To compare the feasibility of performing a complete first trimester fetal anatomy screening between two operators with different levels of experience using the protocol of the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), and to compare the duration of scan and learning curve of each operator as secondary outcomes.

METHODS

A prospective study was conducted on singleton pregnancies at 11⁺⁰-13⁺⁶ weeks of gestation. Transabdominal ultrasound anatomy screening was performed by a maternal fetal medicine (MFM) staff (operator 1) or a first year MFM fellow (operator 2) following ISUOG guidelines. The visibility of fetal structures and time taken by each operator were recorded and analyzed.

RESULTS

Data from 98 participants in operator 1 group and 96 participants in operator 2 group were analyzed. The success rate of visualizing all structures was feasible in 87.8% and 91.7% (p = .370) of cases in operator 1 and operator 2, respectively. The significant improvement in visualization success rate was observed between the first 50 and the last 50 scans in both groups (p = .004 vs. p = .006). Average time spent on the exam by operator 1 was significantly shorter than the time spent by operator 2 (11.3 ± 4.8 min vs. 15.0 ± 6.2 min; p < .001).

CONCLUSION

Completeness of first trimester fetal anatomy screening following ISUOG protocol were feasible with no statistical difference between the two different levels of experienced operators. Moreover, time allocatable with a brief learning curve were demonstrated in both groups.

Detection of structural abnormalities in fetuses with normal karyotype at 11-13 weeks using the anatomic examination protocol of the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG)

Objective: To assess the performance of sonography in the detection of fetal nonchromosomal abnormalities using a standard anatomic examination protocol proposed by International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) at 11⁺⁰-13⁺⁶ weeks.Materials and methods: A prospective observational study was conducted between June 2013-May 2017 in singleton pregnancies attending for a routine scan at 11⁺⁰-13⁺⁶ weeks. All examinations were performed by maternal-fetal medicine specialists certified by the Fetal Medicine Foundation according to the anatomic examination protocol described in the ISUOG guidelines. First-trimester findings were compared to those of the anomaly scan at 20⁺⁰-23⁺⁶ weeks and the postnatal examination. The primary outcome was the detection rate of major structural abnormalities in fetuses with normal karyotype at 11⁺⁰-13⁺⁶ weeks.Results: After excluding 17 chromosomal abnormalities, major fetal structural defects were detected in 57 (1.7%) of the remaining 3361 cases. Of these, 27 (47.3%) were detected at 11⁺⁰-13⁺⁶ weeks, including all cases of acrania (4), exomphalos (4), megacystis (2) and body stalk anomaly (2). Furthermore, there was a first-trimester diagnosis in 36.4% (4/11) of major cardiac defects, 38% (6/16) of limb defects, and 100% (2/2) of facial clefts.Discussion: Targeted ultrasound examination may identify all the so called "always" detectable major abnormalities and a significant proportion of the "sometimes", detectable at 11⁺⁰-13⁺⁶ weeks.

True Reproducibility of UltraSound Techniques (TRUST): systematic review of reliability studies in obstetrics and gynecology

OBJECTIVES

To examine the quality of methods used and the accuracy of the interpretation of agreement in existing studies that examine the reliability of ultrasound measurements and judgments in obstetrics and gynecology.

METHODS

A systematic search of MEDLINE was performed on 25 March 2014, looking for studies that examined the reliability of ultrasound measurements and judgments in obstetrics and gynecology with evaluation of concordance (CCC) or intraclass (ICC) correlation coefficients or kappa as a main objective.

RESULTS

Seven hundred and thirty-three records were examined on the basis of their title and abstract, of which 141 full-text articles were examined completely for eligibility. We excluded 29 studies because they did not report CCC/ICC/kappa, leaving 112 studies that were included in our analysis. Two studies reported both ICC and kappa and were counted twice, therefore, the number used as the denominator in the analyses was 114. Only 16/114 (14.0%) studies were considered to be well designed (independent acquisition and blinded analysis) and to have interpreted the results properly. Most errors occurring in the studies are likely to overestimate the reliability of the method examined.

CONCLUSIONS

The vast majority of published studies examined had important flaws in design, interpretation and/or reporting. Such limitations are important to identify as they might create false confidence in the existing measurements and judgments, jeopardizing clinical practice and future research. Specific guidelines aimed at improving the quality of reproducibility studies that examine ultrasound methods should be encouraged.

Fetal heart defects: potential and pitfalls of first-trimester detection

Congenital heart defects (CHDs) are the leading cause of infant mortality due to birth defects. In the last 15 years, with the shift in screening for aneuploidies to the first trimester, extensive research has concentrated on early screening and detection of CHDs. Early detailed assessment of the fetal heart requires a high level of expertise in early anomaly scanning and fetal echocardiography. However, the detection of major CHDs at 11-13 weeks is influenced by their association with easily detectable markers, such as the nuchal translucency, ductus venosus blood flow and tricuspid regurgitation, and a policy decision as to the objectives of this scan and the allocation of resources necessary to achieve them. The use of transvaginal ultrasound and newer techniques are likely to improve the detection rate. However, the limitations of fetal echocardiography in the first trimester must be borne in mind, and follow-up at mid-gestational echocardiography is prudent in some cases.

Improved detection rate of structural abnormalities in the first trimester using an extended examination protocol

OBJECTIVE

To assess the potential of first-trimester sonography in the detection of fetal abnormalities using an extended protocol that is achievable with reasonable resources of time, personnel and ultrasound equipment.

METHODS

This was a prospective two-center 2-year study of 5472 consecutive unselected pregnant women examined at 12 to 13 + 6 gestational weeks. Women were examined using an extended morphogenetic ultrasound protocol that, in addition to the basic evaluation, involved a color Doppler cardiac sweep and identification of early contingent markers for major abnormalities.

RESULTS

The prevalence of lethal and severe malformations was 1.39%. The first-trimester scan identified 40.6% of the cases detected overall and 76.3% of major structural defects. The first-trimester detection rate (DR) for major congenital heart disease (either isolated or associated with extracardiac abnormalities) was 90% and that for major central nervous system anomalies was 69.5%. In fetuses with increased nuchal translucency (NT), the first-trimester DR for major anomalies was 96%, and in fetuses with normal NT it was 66.7%. Most (67.1%) cases with major abnormalities presented with normal NT.

CONCLUSIONS

A detailed first-trimester anomaly scan using an extended protocol is an efficient screening method to detect major fetal structural abnormalities in low-risk pregnancies. It is feasible at 12 to 13 + 6 weeks with ultrasound equipment and personnel already used for routine first-trimester screening. Rate of detection of severe malformations is greater in early- than in mid-pregnancy and on postnatal evaluation. Early heart investigation could be improved by an extended protocol involving use of color Doppler.

Impact of tissue harmonic imaging on measurement of nuchal translucency thickness

OBJECTIVES

To evaluate the effect of tissue harmonic imaging (THI) on the measurement of fetal nuchal translucency thickness (NT).

METHODS

One-hundred and three pregnant women underwent first-trimester NT measurement according to The Fetal Medicine Foundation criteria. NT was evaluated using conventional ultrasonography (CUS) and THI without modifying any other ultrasound parameter (e.g. gain). For each patient three images with CUS and three images with THI were stored and then measured independently on the ultrasound system by two different operators. The maximum measurements using CUS and THI were compared. Differences between the values of CUS and THI NT measurements were tested using the Wilcoxon signed-rank test. Bland-Altman plots were constructed, and intraobserver and interobserver variabilities were assessed by calculation of the intraclass correlation coefficient. Probability values of < 0.05 were considered significant.

RESULTS

Mean maternal age was 32.8 (range, 20-42) years, mean gestational age at examination was 12 + 1 (11 + 0 to 13 + 6) weeks and mean crown-rump length (CRL) was 55.8 (SD, 7.2) mm. Median fetal NT was 1.4 (0.8-3.5) mm using CUS and 1.2 (0.6-3.3) mm using THI (P < 0.001) for the first operator. A second operator remeasured the first 51 cases: median fetal NT was 1.4 (0.8-3.8) mm using CUS and 1.1 (0.6-3.1) mm using THI (P < 0.001). Fetal NT measurements were above the expected median value according to CRL in 49 cases (47.6%) using CUS and in only 24 cases (23.3%) using THI.

CONCLUSIONS

THI leads to a small, but significant, reduction of the NT measurement and this could reduce the sensitivity of screening for Down syndrome.

13-14-week fetal anatomy scan: a 5-year prospective study

OBJECTIVES

To assess the potential value of an early (first-trimester) ultrasound examination in depicting fetal anomalies by transabdominal (TAS) and transvaginal (TVS) sonography, to compare it with the traditional mid-trimester anomaly ultrasound examination and to evaluate the degree of patient acceptance of early sonography by the transvaginal route.

METHODS

In this prospective study over a 5-year period (January 2002 to January 2007) 2876 pregnant women underwent a 13-14-week ultrasound examination. The scan was performed by TAS at first and then, if a full fetal anatomical survey was not achieved, by TVS. A mid-trimester fetal anatomy scan was then performed in patients who had not dropped out, miscarried or undergone pregnancy termination (n = 2834).

RESULTS

In the early scan, analyzable data for 2876 TAS and 1357 TVS examinations showed that TVS was significantly better in visualizing the cranium, spine, stomach, kidneys, bladder and upper and lower limbs (P < 0.001). Complete fetal anatomical surveys were achieved by TAS in 64% of cases versus 82% of the cases in which it was attempted by TVS (P < 0.001). Patient body mass index significantly affected the ability of the sonographer to achieve a complete anatomical survey by both TAS and TVS (P < 0.001 and P = 0.004, respectively). The duration of the scan was significantly longer using TVS. The heart and kidneys were not properly visualized in 42% and 27% of cases, respectively, at the 13-week scan compared with 1.6% and 0% at the mid-trimester scan. The total number of cases in which anomalies were detected was 31. At the first-trimester scan, anomalies were detected in 21 fetuses and in 14 of these cases the parents chose pregnancy termination. At the second-trimester scan, anomalies were detected in 17 fetuses: 10 new anomalous cases along with seven cases already detected in the first-trimester scan.

CONCLUSION

Besides its importance in screening for chromosomal abnormalities, the early scan has great potential in visualizing with precision fetal anatomy. TVS can be used to compliment difficult TAS examinations; however, patients do not always agree to undergo TVS. The mid-trimester scan remains crucial for detailed fetal anatomical survey.

Fetal abdominal cysts in the first trimester: prenatal detection and clinical significance

OBJECTIVE

In order to determine the clinical significance of fetal abdominal cysts detected in the first trimester, we reviewed our experience with such cases collected over a 5-year period.

METHODS

Five cases in which a fetal abdominal cyst was detected by ultrasound in the first trimester were identified. Information on the ultrasound findings, antenatal course and perinatal outcome was obtained in all cases.

RESULTS

The abdominal cyst was confirmed by an early second-trimester scan at 14-16 weeks in all cases, at which time no associated anomalies were detected. The standard detailed second-trimester scan at 18-22 weeks demonstrated complete resolution in three cases. These women had an uneventful antenatal course, and normal newborn infants were delivered at term. However, one of these infants had intestinal malrotation, chronic abdominal distension and midgut volvulus requiring surgery at the age of 7 months. Among the remaining two cases in which the abdominal cyst persisted, one required prenatal aspiration at 19 weeks owing to significant enlargement and resolved. The other remained stable in size and was managed conservatively, but the infant required surgery at the age of 7 weeks owing to a choledochal cyst causing intermittent episodes of acholia.

CONCLUSION

Abdominal cysts in early pregnancy often resolve spontaneously or remain small and are usually associated with a good outcome. Nevertheless, as they can also be associated with serious underlying gastrointestinal pathological conditions, close surveillance in the perinatal period is advocated.

Congenital diaphragmatic hernia in a first-trimester ultrasound aneuploidy screening program

OBJECTIVES

To review our experience with the prenatal detection of congenital diaphragmatic hernia (CDH) in fetuses presenting for ultrasound screening of chromosomal abnormalities in the first trimester.

METHODS

As part of our first-trimester ultrasound protocol, fetuses with a crown-rump length between 45 and 84 mm underwent a limited anatomical assessment in conjunction with nuchal translucency thickness measurement and nasal bone assessment. Cases of CDH diagnosed prenatally or after delivery in this population were identified.

RESULTS

Among the six cases of CDH detected (prevalence of 1 in 927), the first-trimester ultrasound findings were abnormal in five fetuses (83%), including three with increased nuchal translucency only; one with increased nuchal translucency, an intrathoracic stomach, dextrocardia and a cephalocele; and one with normal nuchal translucency thickness and a small, complex intrathoracic mass later confirmed as the fetal stomach. The diagnosis of CDH was confidently made in the first trimester in one case, in the second trimester in three cases, and after birth in the remaining two cases.

CONCLUSION

The diagnosis of CDH in the first trimester is difficult, especially in those cases in which the defect is small or late migration of the abdominal viscera occurs. Therefore, screening for CDH in the first trimester is unlikely to be effective.

Detailed screening for fetal anomalies and cardiac defects at the 11-13-week scan

OBJECTIVE

To assess the diagnostic efficacy of the first-trimester anomaly scan including first-trimester fetal echocardiography as a screening procedure in a 'medium-risk' population.

METHODS

In a prospective study, we evaluated 3094 consecutive fetuses with a crown-rump length (CRL) of 45-84 mm and gestational age between 11 + 0 and 13 + 6 weeks, using transabdominal and transvaginal ultrasonography. The majority of patients were referred without prior abnormal scan or increased nuchal translucency (NT) thickness, the median maternal age was, however, 35 (range, 15-46) years, and 53.8% of the mothers (1580/2936) were 35 years or older. This was therefore a self-selected population reflecting an increased percentage of older mothers opting for prenatal diagnosis. The follow-up rate was 92.7% (3117/3363).

RESULTS

The prevalence of major abnormalities in 3094 fetuses was 2.8% (86/3094). The detection rate of major anomalies at the 11 + 0 to 13 + 6-week scan was 83.7% (72/86), 51.9% (14/27) for NT < 2.5 mm and 98.3% (58/59) for NT >or= 2.5 mm. The prevalence of major congenital heart defects (CHD) was 1.2% (38/3094). The detection rate of major CHD at the 11 to 13 + 6-week scan was 84.2% (32/38), 37.5% (3/8) for NT < 2.5 mm and 96.7% (29/30) for NT >or= 2.5 mm.

CONCLUSION

The overall detection rate of fetal anomalies including fetal cardiac defects following a specialist scan at 11 + 0 to 13 + 6 weeks' gestation is about 84% and is increased when NT >or= 2.5 mm. This extends the possibilities of a first-trimester scan beyond risk assessment for fetal chromosomal defects. In experienced hands with adequate equipment, the majority of severe malformations as well as major CHD may be detected at the end of the first trimester, which offers parents the option of deciding early in pregnancy how to deal with fetuses affected by genetic or structural abnormalities without pressure of time.