Ultrasonographic findings of fetal aneuploidies in the second trimester--our experiences

Indications, types, and diagnostic implications of prenatal genetic testing in Sub-Saharan Africa: A descriptive study

OBJECTIVE

To describe indications, test types, and results of prenatal diagnostic genetic amniocentesis among Ethiopian pregnant women.

METHODS

This study was a descriptive study on prenatal diagnostic genetic testing among Ethiopian pregnant women with certain indications and it was conducted at St. Paul's Hospital Millennium Medical College (Addis Ababa, Ethiopia) from January 2017 to April 2023. Data on sociodemographic characteristics, genetic testing indications, types, and results were collected electronically. Data were analysed using SPSS version 23.

RESULTS

A total of 159 cases were analysed. The commonest indication for genetic testing among the study subjects was major fetal structural anomalies identified on specialized prenatal anatomic scanning of the index pregnancy detected in 71(44.7%) cases. Down syndrome and Edward syndrome were the commonest genetic aberrations detected accounting for 6.3% (10/159) and 4.4% (7/159), respectively. Among the rare genetic aberration detected were Di-George syndrome (0.6%) and Duchenne muscular dystrophy (0.6%).

CONCLUSION

Findings of our study underscore the importance of diagnostic prenatal testing in a Sub-Saharan Africa setting, as common (trisomy 21&18) and rare genetic defects were identified using this important prenatal diagnostic testing. Considering the implications of detecting chromosomal abnormalities for future counselling and care, carrier state in parents for some chromosomal anomalies, and planning post-natal management of some abnormalities that are associated with aneuploidies (notably cardiac anomalies), initiation of diagnostic prenatal genetic testing service at tertiary public health facilities should be acted up on.

Choroid Plexus Cysts: Single Nucleotide Polymorphism Array Analysis of Associated Genetic Anomalies and Resulting Obstetrical Outcomes

Objective

Choroid plexus cysts (CPC) are pseudocysts in the fetal choroid plexus and can be detected during ultrasound examination. However, the etiology of fetuses with CPC is still unknown. This study aimed to evaluate the genetic anomalies of fetuses with CPC using single nucleotide polymorphism (SNP) array analysis, as well as their obstetrical outcomes.

Patients and Methods

Among 201 fetuses, 108, 69, and 24 had isolated CPC (iCPC), CPC with sonographic soft markers, and CPC with sonographic structural malformations, respectively. All fetuses underwent conventional karyotyping analysis and SNP array analysis.

Results

Among 201 fetuses with CPC, 15 had chromosomal abnormalities (7.5%, 15/201), including nine fetuses with trisomy 18. Further, SNP array results were consistent with the conventional karyotype analysis and additionally revealed 6.0% (12/201) abnormal copy number variations (CNVs). The rates of pathogenic CNVs in fetuses with iCPC, CPC combined with sonographic soft markers, and CPC combined with sonographic structural malformations were 6.5%, 6.0%, and 45.8%, respectively, with significant differences among the groups.

Conclusion

The results of the SNP array affected the obstetrical outcomes. CPC is thus associated with pathogenic CNVs in approximately 10.9% of cases. Therefore, SNP array should be offered for prenatal testing of fetuses with CPC.

Termination of pregnancy following a Down Syndrome diagnosis: decision-making process and influential factors in a Muslim but secular country, Turkey

OBJECTIVES

This study aims to present the termination of pregnancy (TOP) rates and elucidate the decision-making process following a prenatal diagnosis of Trisomy 21 in Turkey.

METHODS

This retrospective single-center study was conducted with 146 pregnant women between January 2016 and December 2019 in a tertiary hospital. Data on maternal characteristics, sonographic findings, indications for chromosome analysis, and educational, religious, and economic factors that can influence the parental decision process were collected.

RESULTS

The TOP rate of Down syndrome (DS) in our center was 78.8%. We concluded that maternal age, earlier diagnosis, indication for chromosome analysis, and previous pregnancies had no effect on the TOP decision. On the other hand, not having a minor or a major sonographic sign, employed mothers, middle- and high-income families, and families having a secondary or higher education tended to terminate the pregnancy affected by DS at statistically higher rates.

CONCLUSIONS

There are many studies worldwide investigating the TOP preferences for DS. However, there is limited data about TOP rates and influential factors affecting the decision-making process in Muslim countries. This study contributes by clarifying the factors in the decision-making process and elucidating perspectives about TOP in a Muslim country with a unique status: Turkey.

Imaging findings in association with altered maternal alpha-fetoprotein levels during pregnancy

Maternal serum alpha-fetoprotein is a valuable laboratory test used in pregnant women as an indicator to detect certain clinical abnormalities. These can be grouped into four main categories: fetal factors, pregnancy complications, placental abnormalities, and maternal factors. Imaging is an invaluable tool to investigate the various etiologies leading to altered maternal serum alpha-fetoprotein. By reading this article, the radiologist, sonologist, or other health care practitioner should be able to define the probable pathology leading to the laboratory detected abnormal maternal serum levels, thus helping the clinician to appropriately manage the pregnancy and counsel the patient.

Can fetal fractions in the cell-free DNA test predict the onset of fetal growth restriction?

Objective To investigate the possible predictive value of fetal fraction in the cell-free DNA (cfDNA) test in pregnancies with early- and late-onset fetal growth restriction (FGR). Methods This retrospective study comprised 247 women who were screened using the cfDNA test for aneuploidies during the first or second trimester and had deliveries at our institution from January 2016 to December 2019. The fetal fractions of women with early- (n = 14) and late-onset (n = 83) FGR and those with uncomplicated pregnancies (n = 150) were compared. Results The median fetal fractions for the early-onset FGR, late-onset FGR, and control groups were 5.7 [interquartile range (IQR) 2.65], 7 (IQR 5), and 7.35 (IQR 3.65), respectively. The fetal fractions were significantly lower in the early-onset FGR group than in the late-onset FGR and control groups (P = 0.047 and P = 0.037, respectively). There was no difference in fetal fractions between the late-onset FGR and control groups (P = 1.00). Conclusion As a placenta-related disease, early-onset FGR had lower fetal fractions in the cfDNA test than uncomplicated pregnancies. For clinical use, lower fetal fractions can contribute as a biomarker for screening asymptomatic women for possible placenta-related diseases, such as early-onset FGR. However, more studies are needed to define the "lower" limit.

Assessment of the Nasal Bone by 2-Dimensional Ultrasound in 2 Different Planes: Do They Give the Same Results?

OBJECTIVES

Measurement of the nasal bone is an important part of the genetic sonogram. This study aimed to compare nasal bone length measurements taken in 2 different planes and to determine whether there is consistency between the measurements.

METHODS

The nasal bone was measured in 103 fetuses whose mothers were admitted to our clinic for second-trimester ultrasound examinations and who did not have any accompanying diseases. In this prospective study, the gestational ages of fetuses ranged from 19 to 23 weeks. Nasal bones were measured in both coronal and midsagittal planes, and the similarity between the measurements was evaluated. Pearson correlation, Wilcoxon signed rank, and Kruskal-Wallis tests were used to evaluate the results.

RESULTS

The median nasal bone length increased with increasing gestational age in both planes, as expected. There were no statistically significant differences between the fetal nasal bone lengths taken in the midsagittal and coronal planes at 19 to 23 weeks' gestation (P > .05).

CONCLUSIONS

The coronal plane may be used as an alternative to evaluate the nasal bone in the second trimester of pregnancy.

Prenatal diagnosis of prevalence of the right heart: associated anomalies and outcome predictors

OBJECTIVES

To analyze the characteristics, associations, and outcomes of prevalence of the right heart and to evaluate the use of sonography to predict the risk of a poor prognosis in fetuses with this condition.

METHODS

We conducted a retrospective cohort study of 182 fetuses with prevalence of the right heart. At the initial evaluation, the left ventricle (LV) and right ventricle (RV) sizes, left atrium and right atrium sizes, great artery diameters, appearance of the aortic arch and ductus arteriosus arch, and flow direction across the foramen ovale and aortic arch were documented. Malformations were documented in fetuses with intracardiac anomalies, who were divided into groups with and without coexisting extracardiac defects. The RV-LV diameter ratio and main pulmonary artery-to-aortic root diameter ratio were calculated and compared. The following variables were analyzed: coexisting intracardiac anomalies, associated extracardiac anomalies, diagnosis before 24 gestational weeks, fetal growth restriction, reversed flow across the foramen ovale, reversed flow in the aortic arch, and RV-LV ratio greater than 2.0. Relationships between these sonographic findings and the prognosis were evaluated by multivariable logistic regression.

RESULTS

Of the 182 fetuses, 1 (0.5%) had intrauterine death, and 25 (13.7%) had neonatal death; 1 (0.5%) had selective reduction, and 106 (58.2%) underwent termination of pregnancy; 49 (26.9%) survived at this writing. The mean RV-LV ratio was 1.67. Multivariable logistic regression revealed that only 2 sonographic parameters, coexisting intracardiac anomalies (odds ratio, 17.75; 95% confidence interval, 4.18-75.26) and diagnosis before 24 weeks (odds ratio, 17.26; 95% confidence interval, 1.80-165.39) were significantly associated with a poor prognosis.

CONCLUSIONS

The sonographic parameters of coexisting intracardiac anomalies and diagnosis before 24 gestational weeks are significant independent predictors of a poor prognosis in fetuses with prevalence of the right heart. Combinations of these risk factors may be useful in prenatal consultation.

Polyhydramnios: Causes, Diagnosis and Therapy

Polyhydramnios is defined as a pathological increase of amniotic fluid volume in pregnancy and is associated with increased perinatal morbidity and mortality. Common causes of polyhydramnios include gestational diabetes, fetal anomalies with disturbed fetal swallowing of amniotic fluid, fetal infections and other, rarer causes. The diagnosis is obtained by ultrasound. The prognosis of polyhydramnios depends on its cause and severity. Typical symptoms of polyhydramnios include maternal dyspnea, preterm labor, premature rupture of membranes (PPROM), abnormal fetal presentation, cord prolapse and postpartum hemorrhage. Due to its common etiology with gestational diabetes, polyhydramnios is often associated with fetal macrosomia. To prevent the above complications, there are two methods of prenatal treatment: amnioreduction and pharmacological treatment with non-steroidal anti-inflammatory drugs (NSAIDs). However, prenatal administration of NSAIDs to reduce amniotic fluid volumes has not been approved in Germany. In addition to conventional management, experimental therapies which would alter fetal diuresis are being considered.

Second trimester prenatal ultrasound for the detection of pregnancies at increased risk of Trisomy 18 based on serum screening

OBJECTIVE

To describe ultrasound findings in fetuses with Trisomy 18.

METHODS

Prospective population-based cohort study of second trimester ultrasound among Californian women who were at increased risk of chromosome abnormality based on serum screening between November 1999 and April 2001. Structural anomalies plus the following soft markers were assessed: nuchal fold thickening, choroid plexus cyst (CPC), echogenic intracardiac focus, echogenic bowel, renal pyelectasis, clenched hands; clinodactyly; short femur, short humerus and a single umbilical artery (SUA).

RESULTS

Overall, 8763 women underwent ultrasound evaluation, including 56 whose fetuses had Trisomy 18. Ultrasound anomalies were seen in 89% of Trisomy 18 fetuses, as compared with 14% of normal fetuses. If the genetic sonogram was normal (no structural anomaly and no soft marker), the risk was reduced by approximately 90%. The ultrasound soft markers were typically seen in conjunction with structural anomalies in affected fetuses and in the absence of a structural anomaly, most isolated ultrasound soft markers were not associated with Trisomy 18. The only exception was an isolated CPC, seen as the only finding in 11% of fetuses with Trisomy 18.

CONCLUSIONS

If the genetic sonogram is used as a sequential test following serum biochemistry, a normal ultrasound study reduces the likelihood of Trisomy 18 substantially even if a woman has abnormal serum biochemistry. The presence of an isolated CPC raises the risk, but not high enough to prompt invasive testing.