The advent of high-resolution transvaginal ultrasound (TVS) has revolutionized our understanding of the pathophysiology and the management of early pregnancy failure. Knowledge of the ultrasound appearances of normal early pregnancy development and a good understanding of its pitfalls are essential for the diagnosis and management of early pregnancy failure. Ultrasound imaging has rapidly replaced all other techniques used to study normal human development in the first trimester, and ultrasound features of the early gestational sac have corroborated anatomical studies showing that the first structures to appear are the celomic cavity and the secondary yolk sac. No single ultrasound measurement of the different anatomical features in the first trimester has been shown to have a high predictive value for determining early pregnancy outcome. Similarly, Doppler studies have failed to demonstrate abnormal blood flow indices in the first-trimester uteroplacental circulation of pregnancies that subsequently end in miscarriage. Ultrasound parameters combined with maternal serum hormone levels, maternal age, smoking habits, obstetric history and the occurrence of vaginal bleeding have all been combined in multivariate analyses, with mixed results. Combined ultrasound and in-vitro experiments have demonstrated that the maternal circulation inside the placenta starts at the periphery at around 9 weeks of gestation and that this is associated with a physiological oxidative stress which could be the trigger for the formation of the placental membranes. Abnormal development of these membranes can result in subchorionic hemorrhage and threatened miscarriage with subsequent long-term consequences such as preterm rupture of the membranes and preterm labor, irrespective of the finding of a hematoma on ultrasound. In both euploid and aneuploid missed miscarriages there is clear ultrasound evidence for excessive entry of maternal blood at a very early stage inside the developing placenta resulting in oxidative stress and subsequent degeneration of villous tissue. The finding of blood flow in the intervillous space in cases of first-trimester miscarriage using color Doppler also appears to be useful in the prediction of success of expectant management. Miscarriages with blood flow within the intervillous space are up to four times more likely to complete with expectant management. TVS is considered the gold standard in the diagnosis and management of incomplete miscarriage. Expectant management of miscarriage, using ultrasound parameters to determine eligibility, could significantly reduce the number of unnecessary evacuations of the retained products of conception, depending on the criteria used.

https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1002/uog.1892

The role of ultrasound imaging in diagnosing and investigating early pregnancy failure

Measurement of embryonic or foetal size using the greatest length of the embryo or foetal crown rump length can be used to accurately determine the gestational age of a normal first trimester pregnancy to within three to five days. Transvaginal ultrasound scan can be used to measure the size of an embryo and gestation sac earlier than transabdominal ultrasound. The original Robinson curve used for dating pregnancies is still valid in most cases. Ultrasound dating in the first trimester is now recommended for all women with spontaneous pregnancies, even those with certain menstrual dates. First trimester growth in normal pregnancy is not uniform and is influenced by both maternal and foetal factors. Early foetal growth restriction is demonstrated in many pregnancies that subsequently end in first trimester miscarriage and is also demonstrated in fetuses with triploidy, trisomy 18 and possibly trisomy 13. Pregnancies which are small at the 11–14 week ultrasound scan appear to be at risk of later intrauterine growth restriction, preeclampsia and preterm delivery. Cross-sectional and serial measurement of foetal growth in the first trimester may be helpful in predicting both miscarriage and adverse late pregnancy outcomes.

Dating and growth in the first trimester.

BACKGROUND: The recent introduction of virtual reality (VR) enables us to use all three dimensions in a three-dimensional (3D) image. The aim of this prospective study was to evaluate an innovative VR technique for automated 3D volume measurements of the human embryo and yolk sac in first trimester pregnancies. METHODS: We analysed 180 3D first trimester ultrasound scans of 42 pregnancies. Scans were transferred to an I-Space VR system and visualized as 3D 'holograms' with the V-Scope volume-rendering software. A semi-automatic segmentation algorithm was used to calculate the volumes. The logarithmically transformed outcomes were analysed using repeated measurements ANOVA. Interobserver and intraobserver agreement was established by calculating intraclass correlation coefficients (ICCs). RESULTS: Eighty-eight embryonic volumes (EVs) and 118 yolk sac volumes (YSVs) were selected and measured between 5 +5 and 12 +6 weeks of gestational age (GA). EV ranged from 14 to 29 877 mm 3 and YSV ranged from 33 to 424 mm 3 . ANOVA calculations showed that when the crown-rump length (CRL) doubles, the mean EV increases 6.5-fold and when the GA doubles, the mean EV increases 500-fold (P < 0.001). Furthermore, it was found that a doubling in GA results in a 3.8-fold increase of the YSV and when the CRL doubles, the YSV increases 1.5-fold (P < 0.001). Interobserver and intraobserver agreement were both excellent with ICCs of 0.99. CONCLUSION: We measured the human EV and YSV in early pregnancy using a VR system. This innovative technique allows us to obtain unique information about the size of the embryo using all dimensions, which may be used to differentiate between normal and abnormal human development.

An innovative virtual reality technique for automated human embryonic volume measurements

Objective To review the biological effects and safety of obstetric ultrasound. Outcome Outline the circumstances in which safety may be a concern with obstetric ultrasound. Evidence Medline was searched, and a review of a document on this subject published by Health Canada and of bibliographies from identified articles was conducted. Values Review by principal authors and the Diagnostic Imaging Committee of the SOGC. The level of evidence was judged as outlined by the Canadian Task Force on the Periodic Health Examination. Benefits, harms and costs Obstetric ultrasound should only be done for medical reasons, and exposure should be kept as low as reasonably achievable (ALARA) because of the potential for tissue heating. Higher energy is of particular concern for pulsed Doppler, colour flow, first trimester ultrasound with a long transvesical path (> 5 cm), second or third trimester exams when bone is in the focal zone, as well as when scanning tissue with minimal perfusion (embryonic) or in patients who are febrile. Operators can minimize risk by limiting dwell time, limiting exposure to critical structures, and following equipment generated exposure information. Recommendations 1. Obstetric ultrasound should only be used when the potential medical benefit outweighs any theoretical or potential risk (II-2A). 2. Obstetric ultrasound should not be used for nonmedical reasons, such as sex determination, producing nonmedical photos or videos, or for commercial purposes ( III-B). 3. Ultrasound exposure should be as low as reasonably achievable (ALARA) because of the potential for tissue heating when the thermal index exceeds 1. Exposure can be reduced through the use of output control and (or) by reducing the amount of time the beam is focused on one place (dwell time) (II-1A). 4. All diagnostic ultrasound devices should comply with the output display standards (MI and TI) (III-B). 5. When ultrasound is done for research or teaching purposes, exposed individuals should be informed if either the MI or TI are greater than 1 and how this exposure compares to that found in normal diagnostic practice (III-B). 6. While imaging the fetus in the first trimester, Doppler and colour Doppler should be avoided (III-B).

Ultrasound evaluation of first trimester pregnancy complications.

Objective

Our knowledge about miscarriages mainly concerns pregnancies of at least 8 weeks’ gestation. Information about the morphology and the genetic determinants of early aborted embryos remains limited. In addition, it is known that aneuploidies account for less than half of recurrent spontaneous abortions. We hypothesized that (recurrent) early pregnancy losses might have other genetic causes.



Method

Products of conception from 51 couples with at least one previous miscarriage were collected by hystero-embryoscopy. The extracted DNA was analyzed by low resolution array comparative genomic hybridization and high resolution single nucleotide polymorphism arrays to detect aneuploidies, polyploidies, submicroscopic copy number variants or copy neutral loss of heterozygosity.



Results

Chromosomal aberrations were identified in 65.6% (21/32) of miscarriages and in 89% (8/9) of anembryonic cases. Interestingly, 4/11 chromosomally euploid embryos contained regions of loss of heterozygosity >5 Mb, suggesting the miscarriages might be due to an underlying lethal recessive disease.



Conclusion

Hystero-embryoscopic biopsy followed by array comparative genomic hybridization is a valuable diagnostic tool for early and recurrent miscarriages. Genome-wide high resolution single nucleotide polymorphism microarray analysis of a larger group of miscarriages could provide more insight into the genetic causes of recurrent spontaneous abortion. © 2012 John Wiley & Sons, Ltd.

Cytogenetic and morphological analysis of early products of conception following hystero-embryoscopy from couples with recurrent pregnancy loss

The aim of this retrospetive study was to identify any consistent patterns between ultrasound findings in failed pregnancies and either normal or abnormal karyotypes. The study involved 102 women in whom the diagnosis of early pregnancy failure was made sonographically. The criteria for a failed pregnancy were: a gestational sac with a mean diameter of > 12 mm without a yolk sac; a yolk sac of > 6 mm mean diameter with or without abnormal morphology that ultimately failed to develop an embryonic structure; and an embryo with a crown--rump length (CRL) of > 5 mm without cardiac activity, or the loss of previously identified cardiac activity. All patients underwent elective dilatation and curettage (D & C) and products of conception were sent for karyotyping. Forty-four pregnancies (43%) had abnormal karyotypes. Of these, 33 (75%) were trisomies. The other 11 included four triploidies, one tetraploidy, two with monosomy X, and four others (unbalanced complement, isochromosome, terminal deletion and translocation). Fifty-eight pregnancies (57%) had normal karyotypes, of which 52 were 46,XX and six were 46,XY. The furthest sonographic anatomic landmark achieved did not differ with respect to karyotypic findings. An abnormal yolk sac was found in 10/58 cases (17.2%) with normal karyotypes and 8/44 cases (18.2%) with abnormal karyotypes. There were eight cases of trisomy 16, of which only two manifested an embryonic structure, but neither of which had cardiac activity; the largest was 4 mm. There were four cases of trisomy 22, of which three developed embryos with a CRL of > 10 mm with cardiac activity (11, 11 and 18 mm, respectively). In three cases of mosaicism, embryos developed cardiac activity, and were 9, 19 and 16 mm. Two cases of monosomy X had embryos of 14 and 24 mm. Only one out of five cases with multiple trisomies developed to a point at which any embryonic structure was identifiable on ultrasound examination. The ultrasound appearance of early pregnancy failure in terms of furthest anatomic landmark reached was not significantly different in cases with normal or abnormal karyotype. An abnormally enlarged yolk sac, presumably secondary to hydropic change, is a non-specific finding of failed pregnancy, and did not correlate with karyotypic abnormality (trisomy 22, mosaic, monosomy X) seem to develop further prior to embryonic demise than those with certain others (trisomy 16, multiple trisomies and unusual other variants.

Correlation between karyotype and ultrasound findings in patients with failed early pregnancy

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

C. Papp

Author Tools

Chat about Author

Papers

Correlation between karyotype and ultrasound findings in patients with failed early pregnancy