Umbilical Artery Doppler Ultrasound for the Determination of Chorionicity in Twin Pregnancies
Bibliographic record
Abstract
Background: Maternal and perinatal complications are higher in twins than in singleton pregnancies. This complications rate is directly related to placental chorionicity in twin pregnancies. Early diagnosis of twins and their chorionicity is necessary to reduce the perinatal mortality. It can be determined by different methods in the first trimester. Ultrasonography is a valuable tool in management of twin pregnancy. Ultrasound in evaluation of the chorionicity decreases later in gestational weeks. The aim of this study is to determine the chorionicity by using Doppler ultrasonography in second and third trimesters. Methods: Patients were divided into two groups according to their chorionicity. Pregnancies with dichorionic placentas were included into group 1, while with monochorionic placentas were included into group 2. In both groups, PI, RI and S/D indices of umbilical artery were measured in each fetus. Whether there is a significant difference between the groups in the Doppler parameters was evaluated. Results: The PI, RI and S/D indices of umbilical artery doppler ultrasonography were different between the twins with dichorionic placentas (p < 0.05), but they were similar in twins with monochorionic placentas. Conclusions: Based on our study results, we suggest that the Doppler ultrasonography can be useful method for chorionicity determination of twin pregnancies at second and third trimesters, if chorionicity has not determined until the end of second trimester. doi:10.4021/ jcgo29w
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".