Early prenatal diagnosis of triploidy

Complete Molar Pregnancies with a Coexisting Fetus: Pregnancy Outcomes and Review of Literature

Objective  The objective of the study was to review the obstetric outcomes of complete hydatidiform molar pregnancies with a coexisting fetus (CHMCF), a rare clinical entity that is not well described. Materials and Methods  We performed a retrospective case series with pathology-confirmed HMCF. The cases were collected via solicitation through a private maternal-fetal medicine physician group on social media. Each contributing institution from across the United States ( n  = 9) obtained written informed consent from the patients directly, obtained institutional data transfer agreements as required, and transmitted the data using a Health Insurance Portability and Accountability Act of 1996 (HIPAA) compliant modality. Data collected included maternal, fetal/genetic, placental, and delivery characteristics. For descriptive analysis, continuous variables were reported as median with standard deviation and range. Results  Nine institutions contributed to the 14 cases collected. Nine (64%) cases of CHMCF were a product of assisted reproductive technology and one case was trizygotic. The median gestational age at diagnosis was 12 weeks and 2 days (9 weeks-19 weeks and 4 days), and over half were diagnosed in the first trimester. The median human chorionic gonadotropin (hCG) at diagnosis was 355,494 mIU/mL (49,770-700,486 mIU/mL). Placental mass size universally enlarged over the surveillance period. When invasive testing was performed, insufficient sample or no growth was noted in 40% of the sampled cases. Antenatal complications occurred in all delivered patients, with postpartum hemorrhage (71%) and hypertensive disorders of pregnancy (29%) being the most frequent outcomes. Delivery outcomes were variable. Four patients developed gestational trophoblastic neoplasia. Conclusion  This series is the largest report of obstetric outcomes for CHMCF to date and highlights the need to counsel patients about the severe maternal and fetal complications in continuing pregnancies, including progression to gestational trophoblastic neoplastic disease. Key Points CHMCF is a rare obstetric complication and may be associated with the use of assisted reproductive technology.Universally, patients with CHMCF who elected to manage expectantly developed antenatal complications.The risk of developing gestational trophoblastic neoplasia after CHMCF is high, and termination of the pregnancy did not decrease this risk.

Distribution of diandric and digynic triploidy depending on gestational age

Purpose

To establish the distribution of diandric and digynic triploidy depending on gestational age.

Methods

107 triploid samples tested prospectively in a single genetic department during a four-year period were analyzed for parental origin of triploidy by Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) (n=95) with the use of matching parental samples or by MS-MLPA (n=12), when parental samples were unavailable. Tested pregnancies were divided into three subgroups with regard to the gestational age at spontaneous pregnancy loss: <11 gestational weeks, 11–14 gestational weeks, and >14 gestational weeks.

Results

Diandric triploidy constituted overall 44.9% (46.5% in samples miscarried <11 gestational weeks, 64.3% in samples miscarried between 11 and 14 gestational weeks, and 27.8% in pregnancies which survived >14 gestational weeks).

Conclusions

The distribution of diandric and digynic triploidy depends on gestational age. The majority of diandric triploid pregnancies is lost in the first trimester of pregnancy. In the second trimester, diandric cases are at least twice less frequent than digynic ones.

Triploidy in a Live-Born Extremely Low Birth Weight Twin: Clinical Aspects

Triploidy is a rare chromosomal aberration characterized by a karyotype with 69 chromosomes. Triploid fetuses usually are miscarried in early pregnancy. We present a case of a triploid twin and a genetically unaffected co-twin, conceived through in vitro fertilization. A discordant growth was registered at 20 weeks of gestation. Cesarean section was performed at 355/7 gestational week. The second twin was extremely growth restricted female (780 g) with oligohydramnios and severe respiratory distress, and died at 20 hours of age. The autopsy revealed unilobar left lung, bilobar right lung, and cysts of the terminal bronchioles. Quantitative fluorescent polymerase chain reaction detected triploidy compatible pattern. So, early intrauterine growth restriction may be a sign of triploidy, which must be proven by pre or postnatal genetic testing.

Ultrasound diagnosis of complete and partial hydatidiform moles in early pregnancy failure: An inter-observer study

We evaluated the accuracy of the ultrasound signs suggestive of complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) in a cohort of women with histologically confirmed hydatidiform mole (HM) who presented with early pregnancy failure, including 103 CHM and 95 PHM for which ultrasound images were available. The accuracy of the differential diagnosis was significantly (p < 0.001) greater during secondary examination of ultrasound images compared with the original primary ultrasound examination. The interobserver agreement analysis indicated only a fair to moderate agreement between the two examinations (kappa value 0.41; 95% CI 0.29-0.53). Most HM present as early pregnancy failure and identification of early ultrasound signs can improve the differential diagnosis between CHM and PHM.

Maternal complications in molecularly confirmed diandric and digynic triploid pregnancies: single institution experience and literature review

Objectives

Assessment of the maternal complications in molecularly confirmed diandric and digynic triploid pregnancies.

Methods

Sonographic features, biochemical results, and clinical presentation were analyzed. Beta-hCG level was controlled after diandric triploidy.

Results

The study included nine diandric and twelve digynic triploid pregnancies at the mean gestational age at diagnosis of 14.9 and 18.0 weeks, respectively (p = 0.0391). Mean value of total-hCG was 979 703.6 U/ml in diandric cases and 5 455.4 U/ml in digynic ones (p < 0.000). Maternal complications occurred in 88.9% of diandric triploid pregnancies, including: thecalutein cysts (44.4%), hyperemesis gravidarum (44.4%), symptomatic hyperthyreosis (33.3%), early onset gestational hypertension (22.2%) and vaginal bleeding (11.1%). No case of proteinuria, preeclampsia or HELLP syndrome was observed. Only maternal complication observed in digynic triploidy was vaginal bleeding (50.0%). The mean time of beta-hCG normalization after diandric triploid pregnancies was 84 days (range 11–142 days). No case of gestational trophoblastic neoplasia (GTN) was observed.

Conclusions

Maternal complications (except for vaginal bleeding) are associated with diandric triploidy. The relatively low incidence of hypertensive maternal complications and their less severe course in our cohort may be attributed to the earlier prenatal diagnosis. The frequency of GTN after diandric triploidy may be lower than previously reported.

Prenatal sonographic features can accurately determine parental origin in triploid pregnancies

Objective

To describe the prenatal sonographic features and maternal biochemical markers in triploid pregnancies and to assess whether prenatal phenotype can determine genetic origin.

Methods

We performed a retrospective multicenter cohort study that included all triploid pregnancies diagnosed between 2000 and 2018 in two Fetal Medicine Units in Amsterdam. Fetal growth, presence of structural anomalies, extra‐fetal anomalies, and maternal biochemical markers were retrieved. Asymmetrical intrauterine growth restriction was diagnosed when the head‐to‐abdominal circumference (HC/AC) ratio was >95th centile. Parental origin was analyzed via molecular genotyping in 46 cases (38.3%).

Results

One hundred and twenty triploid pregnancies were identified, of which 86 cases (71.6%) were detected before 18 weeks of gestation. Triploidy of maternal origin was found in 32 cases (69.6%) and was associated with asymmetrical growth restriction, a thin placenta, and low pregnancy‐associated plasma protein A and free beta‐human chorionic gonadotrophin (β‐hCG) levels. Triploidy of paternal origin was found in 14 cases (30.4%) and was associated with an increased nuchal translucency, placental molar changes, and a high free β‐hCG. Prospective prediction of the parental origin of the triploidy was made in 30 of the 46 cases based on phenotypical ultrasound presentation, and it was correct in all cases.

Conclusion

Asymmetrical growth restriction with severe HC/AC discrepancy is pathognomonic of maternal triploidy. Placental molar changes indicate a paternal triploidy. Moreover, triploidy can present with an abnormal first trimester combined test, with serum levels on the extreme end. When available results of maternal serum markers can support the diagnosis of parental origin of the triploidy, an accurate assessment of the parental origin based on prenatal sonographic features is possible, making DNA analysis redundant.

A Pictorial Ultrasound Essay of Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD) includes a wide variety of clinical and histopathologic entities that require prompt identification and definition by the integration of clinical, laboratory, and imaging data. Recently, the role of grayscale ultrasound and spectral and power/color Doppler techniques has become pivotal in the diagnosis, staging, and management of GTD, thanks to both technical improvements and the growing expertise of dedicated operators. The aim of this essay is to summarize the most recent data on the ultrasound and Doppler findings of GTD and to provide a pictorial overview, including useful prognostic and therapeutic implications for clinical practice.

Early prenatal detection of triploidy: a 9-year experience in mainland China

Objective: In this study, we report the indications for prenatal cytogenetic diagnosis of triploid cases, in an attempt to identify clues to early diagnosis.Study design: This was a retrospective analysis of prenatal cases of triploidy during a 9-year period at mainland China. Clinical data were reviewed for these cases, including maternal demographics, indications for invasive testing, fetal ultrasound findings, and pregnancy outcomes.Results: A total of 22 singleton pregnancies affected with triploid fetuses were detected. The fetal karyotype included 69,XXX (72.7%) and 69,XXY (27.3%). Eighteen cases were identified by the first trimester screening program. One case was missed by maternal cell-free DNA testing, but detected by second trimester anatomy scan. Three cases escaped the first trimester screening and were detected by second trimester anatomy scan.Conclusions: The present study demonstrates that most triploid cases can be diagnosed prenatally during the first trimester. The early asymmetrical fetal growth restriction, structural anomalies, and extremely high risk serum screening result for trisomy 21 or 18 should alert the physicians to the investigation of triploidy.Key Message: Ultrasound-based first-trimester screening plays a major role in early diagnosis of fetal triploidy. Future replacement of routine first-trimester screening by cell-DNA testing might miss the chance of early diagnosis and management of triploid pregnancies.

Digynic triploidy in a fetus presenting with semilobar holoprosencephaly

OBJECTIVE

We present digynic triploidy in a fetus with semilobar holoprosencephaly (HPE).

CASE REPORT

A 32-year-old, gravid 1, para 0, woman underwent prenatal ultrasound examination at 12 weeks of gestation, and the ultrasound showed relative macrocephaly, a small non-cystic placenta, and a fetus with absent nasal bone and semilobar HPE. The pregnancy was terminated subsequently, and a 50-g fetus was delivered with a relatively enlarged head and premaxillary agenesis. The placenta was small and non-cystic. Postnatal cytogenetic analysis of the umbilical cord revealed a karyotype of 69, XXX. Postnatal DNA marker analysis using quantitative fluorescent polymerase chain reaction assays and the polymorphic short tandem repeat markers for chromosome 18 and 20 on the placental tissues showed a diallelic pattern with a dosage of 1:2 (paternal allele to maternal allele ratio), indicating a maternal origin of the triploidy.

CONCLUSION

Fetuses with digynic triploidy may present relative macrocephaly, semilobar HPE and a small placenta on prenatal ultrasound.

Fetal fraction-based risk algorithm for non-invasive prenatal testing: screening for trisomies 13 and 18 and triploidy in women with low cell-free fetal DNA

OBJECTIVE

To identify pregnancies at increased risk for trisomy 13, trisomy 18 or triploidy attributable to low fetal fraction (FF).

METHODS

A FF-based risk (FFBR) model was built using data from more than 165 000 singleton pregnancies referred for single-nucleotide polymorphism (SNP)-based non-invasive prenatal testing (NIPT). Based on maternal weight and gestational age (GA), FF distributions for normal, trisomy 13, trisomy 18 and triploid pregnancies were constructed and used to adjust prior risks for these abnormalities. A risk cut-off of ≥ 1% was chosen to define pregnancies at high risk for trisomy 13, trisomy 18 or triploidy (high FFBR score). The model was evaluated on an independent blinded set of pregnancies for which SNP-based NIPT did not return a result, and for which pregnancy outcome information was gathered retrospectively.

RESULTS

The evaluation cohort comprised 1148 cases, of which approximately half received a high FFBR score. Compared with rates expected based on maternal age (MA) and GA, cases with a high FFBR score had a significantly increased rate of trisomy 13, trisomy 18 or triploidy combined (5.7% vs 0.7%; P < 0.001) and also of unexplained pregnancy loss (14.7% vs 10.4%; P < 0.001). For cases that did not receive a high FFBR score, the incidence of a chromosomal abnormality or pregnancy loss was not significantly different from that expected based on MA and GA. In this study cohort, the sensitivity of the FFBR model for detection of trisomy 13, trisomy 18 or triploidy was 91.4% (95% CI, 76.9-98.2%) with a positive predictive value of 5.7% (32/564; 95% CI, 3.9-7.9%).

CONCLUSIONS

For pregnancies with a FF too low to receive a result on standard NIPT, the FFBR algorithm identified a subset of cases at increased risk for trisomy 13, trisomy 18 or triploidy. For the remainder of cases, the risk of a fetal chromosomal abnormality was unchanged from that expected based on MA and GA. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Distribution of PAPP-A and total hCG between 11 and 13 weeks of gestation in Japanese pregnant women

Objectives: To establish the reference values for PAPP-A and total hCG between 11 and 13 weeks of gestation for the use of risk assessment of fetal aneuploidy in Japanese pregnant women.Methods: A multicenter prospective study was conducted. The subjects included only Japanese pregnant women with viable singleton who requested the first trimester combined (nuchal translucency and maternal serum marker) screening for fetal aneuploidy. Reference values of PAPP-A and total hCG in Japanese population were made and compared with them in Caucasian.Results: Overall 1,751 Japanese pregnant women were analyzed. Median vales of maternal serum concentration in Japanese pregnant women from 11 + 0-13 + 6 weeks' gestation were ranged from 3.01 to 9.51 mIU/mL for PAPP-A and from 70.2 to 58.3 IU/mL for total-hCG, respectively. Regression curve of median maternal serum PAPP-A and total-hCG concentration against gestational days are significantly higher in Japanese comparing with Caucasian. At most distant values, Japanese serum concentration indicated 1.45 MoM for total-hCG and 1.70 MoM for PAPP-A based on Caucasian regression curves.Conclusion: A modification of the equations by specific reference values is necessary for Japanese pregnant women at the risk assessment of chromosomal abnormalities using the first trimester maternal serum marker.

Radiological Aspect of Klippel-Trénaunay Syndrome: A Case Series With Review of Literature

Klippel-Trénaunay syndrome (KTS) is a rare angio-osteo-hypertrophic syndrome characterized by vascular malformations, soft tissue and/or bone hypertrophy, and varicose veins. For the purpose of describing the imaging findings and elucidating the role of medical imaging in the diagnosis and assessment of patient with KTS, we have reviewed the imaging data of 14 KTS patients. The imaging features on different imaging modalities were analyzed. Unilateral lower limb involvement was evident in 71% of cases (n=10) and bilateral but asymmetric lower limb involvement in the remaining 29% of cases (n=4). The most commonly depicted imaging features were varicosities in 93% (n=13), muscle hypertrophy in 79% (n=11) and venous anomalies in 64% (n=9). Other less common imaging findings included lymphedema in 29% (n=4), arterial malformations 29% (n=4), soft tissue hemangiomas 21% (n=3), pelvic and thigh phleboliths 21% (n=3), venous aneurysms 21% (n=3), bone abnormalities 14% (n=2) and lymphadenopathy 14% (n=2). A severe unilateral lower limb deformity resulting in contractures and muscle atrophy of the whole limb was depicted in 1 case. The pathognomonic marginal vein of Servelle was identified in 2 cases. AV shunt was highly suspected in 4 cases and was confirmed by DSA in 1 case, making Klippel-Trénaunay-Weber syndrome a more apt diagnosis. Associated ipsilateral duplicated renal artery was found in 1 case. We have concluded that medical imaging is the cornerstone in the diagnosis and assessment of severity and complications, follow-up and differentiation of KTS from other similar conditions. Different imaging modalities play complementary roles in the evaluation of KTS patients.

Genetic Counseling and Prenatal Diagnosis of Triploidy During the Second Trimester of Pregnancy

Introduction:

Triploidy is a lethal chromosomal numeric abnormality, characterized on extra haploid set of chromosomes. It occurs in 2 to 3% of conceptuses and accounts for approximately 20% of chromosomally abnormal first-trimester miscarriages. As such, triploidy is estimated to occur in 1 of 3,500 pregnancies at 12 weeks’, 1 in 30,000 at 16 weeks’, and 1 in 250,000 at 20 weeks’ gestation.

Case report:

We present a case of second-trimester triploidy diagnosed prenataly at our center. 28-years-old gravida with a first spontaneous pregnancy had early gestational hypertension. Ultrasound examination in 14^6/7 weeks’ gestation revealed asymmetric intrauterine growth retardation. We recommended biochemical maternal serum screening during second trimester of pregnancy (AFP, HCG, uE3). Result of biochemical screening was indication for cytogenetic analysis from amniotic fluid cells and we recommended early amniocentesis in 15^6/7 weeks’ gestation. Result showed abnormal karyotype of the fetus (69,XXX triploidy), and DNA analysis confirmed Type-2 Diginy. Parents decided to terminate this pregnancy, and it was done at 22 weeks’ gestation.

Conclusion:

We emphasize the importance of non-invasive prenatal exminationes-biochemical serum screening during second trimester of pregnancy, and ultrasound examinations in prenatal screening of syndroma Down and other chromosomal abnormalities.

Update and Review: Maternal Serum Screening

Maternal serum levels of alpha fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) can be used to screen pregnancies for neural tube defects, Down syndrome, Trisomy 18, and pregnancy complications. This article summarizes the most recent information regarding maternal serum screening, including genetic counseling issues.

Triploid pregnancies: genetic and clinical features of 158 cases

OBJECTIVE

The purpose of this study was to analyze the correlation between the genetic constitution and the phenotype in triploid pregnancies.

STUDY DESIGN

One hundred fifty-eight triploid pregnancies were identified in hospitals in Western Denmark from April 1986 to April 2010. Clinical data and karyotypes were collected retrospectively, and archived samples were retrieved. The parental origin of the genome, either double paternal contribution (PPM) or double maternal contribution (MMP) was determined by an analysis of methylation levels at imprinted sites.

RESULTS

There were significantly more PPM than MMP cases (P < .01). In MMP cases, the possible karyotypes had similar frequencies, whereas, in PPM cases, 43% had the karyotype 69,XXX, 51% had the karyotype 69,XXY, and 6% had the karyotype 69,XYY. Molar phenotype was seen only in PPM cases. However, PPM cases with a nonmolar phenotype were also seen. For both parental genotypes, various fetal phenotypes were seen at autopsy. Levels of human chorionic gonadotropin in maternal serum were low in MMP cases and varying in PPM cases, some being as low as in the MMP cases.

CONCLUSION

In a triploid pregnancy, suspicion of hydatidiform mole at ultrasound scanning, by macroscopic inspection of the evacuated tissue, at histology, or because of a high human chorionic gonadotropin in maternal serum level each predict the parental type PPM with a very high specificity. In contrast, the sensitivity of these observations was <100%.

Detection of triploidy at 11-14 weeks' gestation: a cohort study of 198 000 pregnant women

OBJECTIVES

To assess the detection rate of triploidy at first-trimester screening for trisomy 21 and evaluate outcome in triploid pregnancies.

METHODS

From 2008 to 2011, 198 427 women with singleton pregnancies underwent first-trimester screening between 11 + 2 and 14 + 0 weeks' gestation. Screening parameters included nuchal translucency, maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A). In all triploid fetuses, these parameters were re-evaluated. Karyotypes were established by invasive testing (chorionic villus sampling or amniocentesis) or postabortem and obtained from the Danish Cytogenetic Central Register and the Danish Fetal Medicine Database.

RESULTS

A total of 30 triploid fetuses underwent first-trimester screening. Twenty-five were diagnosed as a result of abnormal first-trimester scan findings, a detection rate of 83.3%. Twenty-three fetuses were identified due to a high risk for trisomy 13, 18 or 21 and two fetuses due to structural abnormalities. The incidence of triploidy at first-trimester screening was 1:6614. A smaller crown-rump length than that estimated by date of last menstrual period was found in 95% of the fetuses with data available for evaluation. Eight fetuses had a larger biparietal diameter than expected for gestational age. Fetuses with a 69,XXX karyotype had significantly lower multiples of the median values for β-hCG and PAPP-A than did 69,XXY fetuses (P = 0.045 and P = 0.02 forβ-hCG and PAPP-A, respectively). No infants with triploidy were born in the study period. Among the triploid gestations detected on first-trimester screening, 20 (80.0%) women chose termination of pregnancy, four (16.0%) had spontaneous miscarriage and one (4.0%) was stillborn.

CONCLUSION

First-trimester screening for trisomy 21 also provides a high detection rate for triploidy.

Prenatal detection of fetal triploidy from cell-free DNA testing in maternal blood

OBJECTIVE

To investigate potential performance of cell-free DNA (cfDNA) testing in maternal blood in detecting fetal triploidy.

METHODS

Plasma and buffy coat samples obtained at 11-13 weeks' gestation from singleton pregnancies with diandric triploidy (n=4), digynic triploidy (n=4), euploid fetuses (n=48) were sent to Natera, Inc. (San Carlos, Calif., USA) for cfDNA testing. Multiplex polymerase chain reaction amplification of cfDNA followed by sequencing of single nucleotide polymorphic loci covering chromosomes 13, 18, 21, X, and Y was performed. Sequencing data were analyzed using the NATUS algorithm which identifies copy number for each of the five chromosomes.

RESULTS

cfDNA testing provided a result in 44 (91.7%) of the 48 euploid cases and correctly predicted the fetal sex and the presence of two copies each of chromosome 21, 18 and 13. In diandric triploidy, cfDNA testing identified multiple paternal haplotypes (indicating fetal trisomy 21, trisomy 18 and trisomy 13) suggesting the presence of either triploidy or dizygotic twins. In digynic triploidy the fetal fraction corrected for maternal weight and gestational age was below the 0.5th percentile.

CONCLUSIONS

cfDNA testing by targeted sequencing and allelic ratio analysis of single nucleotide polymorphisms covering chromosomes 21, 18, 13, X, and Y can detect diandric triploidy and raise the suspicion of digynic triploidy.

Distribution of nuchal translucency thickness in Japanese fetuses

AIM

To establish reference values for the nuchal translucency (NT) thickness in Japanese fetuses.

MATERIAL AND METHODS

Ultrasonographic measurements of the crown-rump length (CRL) and NT were performed from 11 to 13 + 6 weeks of gestation in consecutive Japanese fetuses examined during prenatal visits between February 2011 and January 2012. The median, 5th and 95th percentiles of the NT thickness with 5 mm intervals of the CRL were confirmed.

RESULTS

A total of 970 cases were enrolled in the study. The median NT thickness for a CRL between 45 and 80 mm ranged from 1.2 mm to 1.9 mm, and the 95th percentile of these values ranged from 2.1 mm to 3.2 mm, respectively.

CONCLUSION

The reference values for the NT thickness in Japanese fetuses were determined. These values should be useful for fetal biometry, morphological assessment and first trimester screening for chromosomal abnormalities in Japan.

Absent mandibular gap in the retronasal triangle view: a clue to the diagnosis of micrognathia in the first trimester

OBJECTIVE

To describe a new ultrasound technique that may be useful for the diagnosis of micrognathia in the first trimester of pregnancy.

METHODS

The retronasal triangle (RNT) view is a technique that captures the coronal plane of the face in which the primary palate and the frontal processes of the maxilla are visualized simultaneously. Normal first-trimester fetuses display a characteristic gap between the right and left body of the mandible in this view (the 'mandibular gap'). The presence or absence of this gap was evaluated and measured prospectively during real-time scanning (n = 154) and retrospectively by analyzing three-dimensional (3D) datasets (n = 50) in normal first-trimester fetuses undergoing screening for aneuploidy at 11-13 weeks' gestation. 3D datasets from 12 fetuses with suspected micrognathia were also collected and examined retrospectively for the same features.

RESULTS

The mandibular gap was identified in all 204 normal fetuses and increased linearly with increasing crown-rump length (y = 0.033x + 0.435; R(2) = 0.316), with no statistically significant differences between measurements obtained by two-dimensional ultrasound and 3D offline analysis. Among fetuses with suspected micrognathia, three 3D datasets were excluded from analysis because of poor image quality in one and the diagnosis of a normal chin in two. In the remaining nine fetuses, the mandibular gap was absent and was replaced by a bony structure representing the receding chin in seven (77.8%) cases and was not visualized due to severe retrognathia in the remaining two (22.2%) cases. All fetuses with micrognathia had associated anomalies, including seven with aneuploidy and two with skeletal dysplasia.

CONCLUSIONS

The RNT view may be a helpful technique for detecting micrognathia in the first trimester. The absence of the mandibular gap or failure to identify the mandible in this view is highly suggestive of micrognathia and should prompt a targeted ultrasound scan to assess for other anomalies. Further research is needed to determine the false-positive and false-negative rates of this technique.

Twin gestation with complete hydatidiform mole and a coexisting live fetus: case report and brief review of literature

Complete hydatidiform (also referred to as hydatiform) mole with coexisting live fetus is an exceedingly rare event. The fetus usually has a normal karyotype, and approximately 25-40% chance of survival, if pregnancy is allowed to continue until reasonable fetal lung maturity is achieved. However, risk of maternal complications including preeclampsia and subsequent trophoblastic disease are significant. We report a case of a 19-year-old primigravida, at 25 weeks gestation with a complete hydatidiform mole and a coexisting live fetus. She developed severe preeclampsia with uncontrolled hypertension, and pregnancy was terminated by caesarean section, after a short course of dexamethasone to accelerate fetal lung maturity. A morphologically normal live female fetus and placenta were delivered without complications, along with a separate mass of complete mole. The postpartum course was complicated by uterine choriocarcinoma with metastases to lung and left kidney, which responded to chemotherapy. Our case is a rare example of a twin gestation composed of a complete hydatidiform mole with a coexisting live fetus, and illustrates the associated spectrum of maternal complications that mandate close pre- and post-natal surveillance.

Clinical findings of multiple pregnancy with a complete hydatidiform mole and coexisting fetus

OBJECTIVE

The aim of this series was to evaluate the clinical features, management, and outcomes of multiple pregnancy with a complete hydatidiform mole and coexisting fetus (CHMCF).

METHODS

Between 1998 and 2008, we investigated 6 women with a diagnosis of a CHMCF. The gestational age at diagnosis, symptoms, serum b-human chorionic gonadotropin levels, cytogenetic and molecular analysis findings, complications, routes of delivery, and pregnancy outcomes were assessed.

RESULTS

All cases were diagnosed before 14 weeks' gestation by sonography. Only 1 ended with the delivery of a live-born neonate, whereas the other 5 cases required termination of pregnancy (TOP) before 21 weeks' gestation because of severe maternal complications (eg, preeclampsia, thyrotoxicosis, lung metastasis, and heavy bleeding) or intrauterine fetal death. The pathologic diagnosis of a complete hydatidiform mole was confirmed in all cases. Two patients required methotrexate for treatment of persistent trophoblastic disease (PTD).

CONCLUSIONS

On the basis of our experience, in cases with a normal karyotype and no gross fetal abnormalities on sonography, we carefully recommend continuation of pregnancy as long as maternal complications are absent or controllable. However, updated treatment criteria are still needed, and intensive maternal follow-up is necessary in the postpartum period because maternal complications during pregnancy and PTD after TOP are not uncommon.

Fetal and placental malignancies: prenatal diagnosis and management

Fetal and placental malignancies are rare complications during pregnancy, but when they occur they may present significant challenges for the perinatology team. Owing to their rarity, there is limited information on many of these entities, with much data derived from individual case reports or small case series. Prenatal diagnosis of these entities is rare and inconsistent, usually in the form of isolated case reports. In the majority of fetal tumors, prenatal features are those of a mass lesion, with or without other non-specific features of fetal compromise such as polyhydramnios, fetal hydrops or intrauterine death, the final diagnosis in most cases being based on postnatal pathological examination.Expectant management is almost always indicated antenatally, with serial ultrasound examinations performed to detect rapid enlargement, metastasis or secondary fetal complications, such as non-immune hydrops, which may require intervention. Delivery should be planned in a specialist center in conjunction with pediatric surgeons and oncologists to allow appropriate neonatal management. Placental malignancy is most commonly in the form of gestatational trophoblastic disease, which requires assessment and management in specialist centers.

First trimester ultrasonography in screening and detection of fetal anomalies

An obstetrical ultrasound examination provides invaluable information regarding the fetus. Until the mid-1980s, ultrasound in the first trimester was limited to localization of the pregnancy, establishing viability, and accurate dating. With the advent of high-resolution ultrasound and transvaginal scanning, a significant amount of information about the fetus can be gained and provided to the patient at a very early stage in gestation. This article provides an overview of the role of first trimester (11-13 + 6 weeks' gestation) ultrasound in screening and diagnosis of fetal anomalies. The first trimester is an ideal time for screening for aneuploidy, primarily due to the advantages that nuchal translucency (NT) measurement provides. NT measurement is also useful in establishing the risk of congenital cardiac disorders and a number of genetic and non-genetic syndromes. Significant NT thickening is associated with an increase in perinatal morbidity and mortality. Potential mechanisms resulting in increased NT are discussed. A number of new ultrasound markers for fetal aneuploidy have been investigated over the past several years, some of which appear to improve the screening efficacy of early ultrasonography. The role of these is reviewed. A number of fetal anomalies can now be consistently diagnosed in the first trimester. Their appearance at this early gestational age is discussed as well. It is clear that, data obtained by first trimester ultrasound are useful in counseling expectant parents and in planning the appropriate follow-up.

First-trimester fetal limb biometry in Chinese population

OBJECTIVES

To establish reference ranges for fetal limb biometry obtained by transabdominal ultrasound examination at 12-14 weeks of gestation in Chinese women.

METHODS

A total of 1489 normal singleton fetuses between 12(+0) and 14(+6) weeks of gestation were examined transabdominally by two experienced observers. The gestation was ascertained by measurement of fetal crown-rump length (CRL) or biparietal diameter (BPD) and head circumference (HC). The lengths of the humerus and femur were prospectively worked out.

RESULTS

Gestation-specific reference ranges for limb measurements were calculated. The femur length (FL) (mean +/- SD) was 9.15 +/- 1.44 mm at 12-12(+6) weeks, 11.45 +/- 1.35 mm at 13-13(+6) weeks, and 13.64 +/- 1.60 mm at 14-14(+6) weeks; the corresponding humerus length (HL) (mean +/- SD) was 9.63 +/- 1.44 mm, 12.01 +/- 1.41 mm, 14.29 +/- 1.48 mm, respectively.

CONCLUSIONS

There was a general increase in fetal limb biometry with gestation. Fetal limb length can be an early marker of early growth restriction as well as fetal skeletal dysplasia among women in the local population.

Relation Between Increased Fetal Nuchal Translucency Thickness and Chromosomal Defects

OBJECTIVE

To examine the prevalence and distribution of all chromosomal defects in fetuses with increased nuchal translucency thickness.

METHODS

Assessment of risk for trisomy 21 was carried out by a combination of maternal age and fetal nuchal translucency thickness at 11-13 + 6 weeks. A search of the database was made to identify, first, all singleton pregnancies in which fetal karyotyping was carried out and, second, the cases where the fetal nuchal translucency was equal to or above the 95th centile for fetal crown-rump length. The prevalence and distribution of chromosomal defects were determined for each nuchal translucency category: between the 95th centile for crown-rump length and 3.4 mm, 3.5-4.4 mm, 4.5-5.4 mm, 5.5-6.4 mm, 6.5-7.4 mm, 7.5-8.4 mm, 8.5-9.4 mm, 9.5-10.4 mm, 10.5-11.4 mm, and 11.5 mm or more.

RESULTS

The search identified 11,315 pregnancies. The median maternal age was 34.5 (range 15-50) years, and the median fetal crown-rump length was 64 (range 45-84) mm. The fetal karyotype was abnormal in 2,168 (19.2%) pregnancies, and the incidence of chromosomal defects increased with nuchal translucency thickness from approximately 7% for those with nuchal translucency between the 95th centile for crown-rump length and 3.4 mm to 75% for nuchal translucency of 8.5 mm or more. In the majority of fetuses with trisomy 21, the nuchal translucency thickness was less then 4.5 mm, whereas in the majority of fetuses with trisomies 13 or 18 it was 4.5-8.4 mm, and in those with Turner syndrome it was 8.5 mm or more.

CONCLUSION

In fetuses with increased nuchal translucency, approximately one half of the chromosomally abnormal group is affected by defects other than trisomy 21. The distribution of nuchal translucency is different for each type of chromosomal defect.

LEVEL OF EVIDENCE

II-3.

Cardiac Circumference Measurement: Possible Screening Tool in Early Pregnancy for Anomalous Cardiac Development

OBJECTIVE

In this study, cardiac circumference (CC), measured by transvaginal sonography, was analyzed to determine the growth during the early stage of pregnancy and its relationship to abdominal circumference and femur length (FL).

METHODS

Biometric measurements, including CC, were obtained in 1,182 euploid fetuses at 9-16 weeks' gestation. The CC measurements were related to gestational age (GA), abdominal circumference, and FL. The corresponding 95% confidence intervals were calculated.

RESULTS

A linear growth function was observed between CC (mm) and GA (days) (r2 = 0.601; p < 0.0001; y = 0.573 GA - 24.185). Similarly, a good correlation is described with a linear function between CC (mm) and abdominal circumference (mm) (r2 = 0.70; p < 0.0001; y = 0.343 AC + 3.696) and between CC (mm) and FL (mm) (r2 = 0.626; p < 0.0001; y = 1.335 FL + 14.444). The regression analysis that best correlates the dependent variable CC (mm) with the independent variables, GA (days), abdominal circumference (mm), and FL (mm), is: y = 0.137 GA + 0.235 AC + 0.199 FL - 3.303 (r2 = 0.708; p < 0.0001).

CONCLUSION

Our results provide normative data of the growth of the CC in early pregnancy. The good correlation described between CC and abdominal circumference and FL suggests that cardiac measurements in early pregnancy alone, or related to other fetal biometric parameters, could be used as a screening tool to identify fetuses at risk for abnormal heart development.

Fetal head-to-trunk volume ratio in chromosomally abnormal fetuses at 11 + 0 to 13 + 6 weeks of gestation

OBJECTIVE

To determine the pattern of early growth disturbance in chromosomally abnormal fetuses by comparing the volume of the fetal head to that of the trunk.

METHODS

The fetal trunk and head volume was measured using three-dimensional (3D) ultrasound in 145 chromosomally abnormal fetuses at a median gestational age of 12 (range, 11 + 0 to 13 + 6) weeks. The head volume was measured separately and then subtracted from the total head and trunk volume to obtain the volume of the fetal trunk. The head-to-trunk ratios were then calculated and the Mann-Whitney U-test was used to determine the significance of differences from 500 chromosomally normal fetuses.

RESULTS

The fetal head volume for crown-rump length (CRL) was significantly smaller than normal in trisomy 21, trisomy 13 and Turner syndrome (P < 0.001, P < 0.001 and P = 0.001, respectively), whereas no significant differences were found in trisomy 18 and triploidy (P = 0.139 and P = 0.070, respectively). The fetal trunk volume for CRL was significantly smaller in all chromosomal abnormalities (P < 0.001) except Turner syndrome (P = 0.134). The head-to-trunk ratio for CRL was significantly larger in trisomy 18, trisomy 13 and triploidy (P < 0.001), but normal in trisomy 21 (P = 0.221) and Turner syndrome (P = 0.768).

CONCLUSIONS

In trisomy 21 and Turner syndrome, the growth deficit was symmetrical with the head and trunk being equally affected, whereas in triploidy and trisomies 18 and 13 there was asymmetrical growth restriction with the trunk being more severely compromised than the head.

Fetal trunk and head volume in chromosomally abnormal fetuses at 11+0 to 13+6 weeks of gestation

OBJECTIVE

To examine the pattern of growth in chromosomally abnormal fetuses at 11+0 to 13+6 weeks of gestation and compare the trunk and head volume to crown-rump length (CRL) in defining the growth deficit in such fetuses.

METHODS

The fetal trunk and head volume was measured using three-dimensional (3D) ultrasound in 140 chromosomally abnormal fetuses at 11+0 to 13+6 (median 12) weeks of gestation, and the values were compared to 500 chromosomally normal fetuses. In each chromosomally abnormal fetus, the observed fetal trunk and head volume was subtracted from the expected mean (delta value) of the chromosomally normal fetuses of the same gestational age, and this difference was expressed as a percentage of the appropriate normal mean. The Mann-Whitney U-test was used to determine the significance of differences between the chromosomally normal and abnormal groups.

RESULTS

In trisomy 21 (n=72) and Turner syndrome (n=14) fetuses, compared to chromosomally normal fetuses, the CRL for gestation was similar (P=0.335 and P=0.317, respectively), but the fetal trunk and head volume was about 10-15% lower (P<0.001 and P=0.004, respectively). In trisomy 18 (n=29), trisomy 13 (n=14) and triploidy (n=11), the deficit in volume was about 45% (P<0.001), whereas the deficit in CRL was less than 15% (P<0.001).

CONCLUSIONS

In the quantification of the degree of early growth impairment in chromosomally abnormal fetuses, measurement of the fetal trunk and head volume using 3D ultrasound may be better than measurement of CRL.

Fetal trunk and head volume measured by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks of gestation in chromosomally normal pregnancies

OBJECTIVE

To establish the relationship between fetal trunk and head volume measured by three-dimensional (3D) ultrasound and gestational age at 11 + 0 to 13 + 6 weeks of gestation.

METHODS

The fetal trunk and head volume were measured using 3D ultrasound in 417 chromosomally normal fetuses from singleton pregnancies at 11 + 0 to 13 + 6 (median, 12 + 0) weeks of gestation. Regression analysis was used to determine the significance of the association between fetal volume and gestational age. The Bland-Altman analysis was used to compare the measurement agreement and bias for a single examiner and between different examiners.

RESULTS

The fetal trunk and head volume increased linearly with gestation from a mean of 5.8 mL at 11 + 0 weeks to 33.3 mL at 13 + 6 weeks and 1 SD was 4.4 mL. There was also a significant linear association between fetal volume and crown-rump length (CRL), from a mean of 5.1 mL at a CRL of 45 mm to 37.5 mL at a CRL of 84 mm and 1 SD was 2.7 mL. However, within this gestational range, a doubling in CRL, from a mean of 48 mm at 11 + 0 weeks to 79 mm at 13 + 6 weeks, was associated with a 5-6-fold increase in fetal volume. The mean difference in fetal volume between paired measurements by the same sonographer was -0.87 mL (95% limits of agreement, -2.31 to 4.05 mL) and the mean difference between paired measurements by two sonographers was -1.09 mL (-5.49 to 3.32 mL).

CONCLUSIONS

3D ultrasound can provide a reproducible measurement of the fetal trunk and head volume in early pregnancy. At between 11 + 0 and 13 + 6 weeks there is a 5-6-fold increase in fetal volume but only a doubling in CRL.

Triploidy identified through second-trimester serum screening

OBJECTIVES

To describe the maternal serum marker patterns of triploid pregnancies and estimate the second-trimester prevalence of triploidy.

METHODS

Forty-two cases of triploidy were identified in six serum screening programmes, five in the United Kingdom, one in Canada. This study describes the serum marker patterns, serum screening results for Down syndrome, trisomy 18 and open neural tube defects, and maternal age of these triploidy cases. The risk cut-off levels were > or = 1 in 250 for Down syndrome, > or =2.5 MoMs alpha-fetoprotein for open neural tube defects and > or =1:100 for trisomy 18 screening. The estimated second-trimester prevalence of triploidy was based on 22 triploidy cases ascertained in 599 934 pregnancies from three routine screening programmes, which attempted complete ascertainment of aneuploidy cases.

RESULTS

The observed second-trimester rate of triploidy was 0.37 per 10 000 fetuses. Two different serum marker patterns were seen in triploid pregnancies, distinguished from each other by typically very high or very low levels of total hCG or free beta-hCG. The median maternal ages were respectively 33 years for triploidy with human chorionic gonadotrophin levels < 1.0 MoM, and 26 years for those with hCG levels > or =1.0 MoM. Fifty-seven percent of the pregnancies with a triploid fetus had a risk estimate > or =1:100 for trisomy 18 alone, 10% had an alpha-fetoprotein > or =2.5 MoM, 5% were screen positive for Down syndrome alone, and 19% had an increased risk or positive results for more than one anomaly.

CONCLUSION

The simultaneous use of maternal serum tests designed to screen prenatally for Down syndrome, neural tube defects, and an increased risk of trisomy 18 resulted in a screen-positive result for 90% of pregnancies with triploidy.

First-trimester screening for fetal triploidy at 11 to 14 weeks: a role for fetal biometry

OBJECTIVE

Intrauterine growth restriction in triploidy has been reported as early as in the first trimester. This study was undertaken to evaluate the ability of first-trimester crown rump length (CRL)-based charts to detect triploid fetuses.

MATERIAL AND METHODS

Analysis of fetal biometry in cases of triploidy diagnosed in the first trimester over the last three years. Biometry for abdominal circumference (AC), head circumference (HC) and biparietal diameter (BPD) was analyzed in relation to both gestational age (GA)-based charts and to CRL-based charts.

RESULTS

Five cases of fetal triploidy were diagnosed at 11 to 14 weeks. Screening based on nuchal translucency (NT) and maternal age showed a risk > 1/300 in only one of the 5 cases of triploid fetus. In all of these five cases, CRL-based biometry was grossly abnormal, although it was abnormal in only two of these five cases in relation to GA-based charts.

CONCLUSION

First-trimester CRL-based biometry charts seem to reflect early asymmetrical growth delay in triploidy more accurately than GA-based charts. CRL-based biometry is likely to improve the early detection of triploid pregnancies without leading to dating error.

Complete hydatidiform mole with coexistent live fetus in dichorionic twin gestation

CASE REPORT

A 28-year-old patient gravida 3, para 2 was admitted at 16 weeks' gestation with the diagnosis of complete hydatidiform mole with coexistent live fetus (CHMCF) in dichorionic twin gestation. The betaHCG level was 530,000 mIU/ml. The pregnancy was terminated by hysterotomy.

OUTCOME

Histopathologic analysis revealed a hydatidiform mole and a 17-week-old male fetus attached to the normal looking placenta by a double-vesseled cord. A final karyotype on cord blood samples confirmed normal 46 XY. Weekly performed serial betaHCG values showed declining trend and were undetectable by 10 weeks post delivery.

The influence of image magnification in first-trimester screening for Down syndrome by fetal nuchal translucency in Asians

OBJECTIVE

The aim of this prospective study was to evaluate the impact of image magnification in the measurements of crown-rump length (CRL) and nuchal translucency (NT) thickness for first-trimester Down syndrome screening in Asians.

METHODS

Ultrasound measurements of NT and CRL were performed in 561 consecutive Taiwanese unaffected fetuses and 11 cases of Down syndrome fetuses between 12 and 14 weeks of gestation. All sonographic images were measured by one qualified examiner to prospectively undergo first-trimester NT screening for Down syndrome. Fetal CRL and NT thickness were measured on three separated images including the original image, regular image, and the magnified image.

RESULTS

A significant mean difference (0.59 +/- 4.24 mm) of CRL was found between measurements on the original and regular image (p < 0.001). There was a significant mean difference of NT thickness measurements between the regular and magnified image (0.12 +/- 0.25 mm, p < 0.001). Seven out of the 11 cases (63.6%) of Down syndrome with NT thickness > or =2.5 mm was measured on three separated images. A significantly reduced incidence of NT thickness > or =2.5 mm on the magnified image was noted than those of the original and regular image measurements in unaffected cases (p < 0.001). Either using the assessing method by the 95th centile cutoff value of NT thickness or combined risk, our results could achieve observed detection rate of 63.6% measured on three separated images.

CONCLUSIONS

Our data indicate that the image magnification could reduce the false-positive rate by using a fixed cutoff value of NT thickness, but would have no influence on the results when using the assessing method either by the 95th centile cutoff value of NT thickness or the combined risk. In order to place the caliper more accurately, a magnified image should be recommended as a standard image in the measurements of the NT thickness.

Ethmocephaly caused by de novo translocation 18;21--prenatal diagnosis

Ethmocephaly is a rare anomaly associated with partial failure of cleavage of the prosencephalon. Morphologically, it is closely related to cyclopia. We present an extremely rare case of ethmocephaly diagnosed in utero and caused by an unbalanced de novo translocation 18;21.