Efficacy of first trimester transvaginal sonography in detecting normal fetal development.

The transvaginal probe is now commonly used by the obstetrician/gynecologist. The improved resolution offered by the probe makes it easier to study the anatomic development of the first trimester fetus in greater detail. The aim of this study was to define the gestational age at which certain fetal structures become apparent by ultrasound and to screen pregnancies at high risk for development of fetal anomalies that could be detected in the first trimester. Endovaginal ultrasound was performed on 60 pregnant women at 8 to 13 menstrual weeks. Clinical follow-up disclosed 36 normally developed fetuses at delivery, five abnormal scans, and 19 ongoing pregnancies. The results of this study show that it is possible to demonstrate most of the major fetal structures by 13 weeks' gestation. By imaging the fetus transvaginally, detection of fetal anomalies can be accomplished much earlier than with the transabdominal scanning alone.     

Four-dimensional sonographic assessment of fetal movement in the late first trimester

Objective

To evaluate, using four-dimensional (4D) sonography, the frequency of fetal movements during the late first trimester of normal singleton pregnancies.

Methods

Singleton pregnancies were studied—using transvaginal 4D sonography—for 10 minutes at 10-11 and 12-13 weeks of gestation. The frequencies of 5 fetal movements (isolated arm, isolated leg, short trunk, long trunk, and jumping movements) were evaluated.

Results

In the 17 pregnancies studied, the most frequent fetal movements were isolated arm movement at 10-11 weeks and jumping movement at 12-13 weeks. There was a significant difference in the frequency of jumping movement between 10-11 and 12-13 weeks (P < 0.05).

Conclusion

The difference in frequency of 5 fetal movements at 10-11 and 12-13 weeks of gestation may be caused by early neuromuscular development and differentiation of the neuromuscular system.     

Women's perception of transvaginal sonography in the first trimester; in an early pregnancy assessment unit

The objective of this study was to gauge women views of transvaginal sonography in an emergency setting and to study any correlation between their perception of the procedure and their prior knowledge and experience of it. We surveyed women presenting with various complications of the first trimester. Only women who had transvaginal sonography and who gave informed consent were included. Four hundred and twenty-five women were recruited. Transvaginal sonography was considered not embarrassing, acceptable, not painful and not stressful by 378 (88.9%), 417 (98.1%), 419 (98.6%) and 385 (90.6%) of the women respectively. There were no statistically significant differences in the women's perception of the procedure whether they had prior knowledge and previous experience of the procedure or not. The majority of the women perceived transvaginal sonography favourably. Their perception of the procedure was favourable whether they had prior knowledge and previous experience of it or not.     

Rate of spontaneous abortion after first trimester sonographic demonstration of fetal cardiac activity

The incidence of spontaneous abortion once embryonic development has reached the stage of sonographically demonstrable cardiac activity has not been precisely determined in a large population. This retrospective study was designed to determine the risk of pregnancy loss after first trimester sonographic confirmation of fetal cardiac activity. A total of 840 patients were referred for ultrasound examination to the Perinatal Center, University of Cincinnati, between January 1, 1979 and December 31, 1985 who fulfilled the criteria of singleton pregnancy with sonographically visible fetal cardiac activity and crown-rump length consistent with gestational age less than or equal to 12 weeks. Patients were grouped into two categories based on the absence (control) or presence of vaginal bleeding (bleeding) prior to or at the time of the ultrasound examination. The abortion rates for the two groups were 5.2 and 16.4%, respectively (P less than 0.001). The relative risk of abortion in patients with vaginal bleeding was nearly four-fold greater than the control population. In the control group there was a significantly greater incidence of pregnancy loss in the greater than or equal to 34 years age group compared to less than 34 years age patients (4.4 versus 11.1%, P less than 0.05). Although there was no significant effect of race on abortion rates, low socioeconomic status almost doubled the relative risk of miscarriage. We conclude that the presence of visible fetal cardiac activity in the first trimester predicts a decreased risk for spontaneous abortion compared to generally reported rates. The significant risk factors for increased chance of abortion are vaginal bleeding, advanced maternal age, and low socioeconomic status.     

Interobserver variation in ovarian measurements using transvaginal sonography

Ultrasound examination of ovarian size and morphology has been proposed as a screening method for ovarian carcinoma. A screening test must give consistent results when performed by different examiners to reliably determine the sensitivity and specificity of the test. This study was designed to evaluate interobserver variation in ovarian size measurements using transvaginal sonography. Two examiners independently measured 86 ovaries in three planes and ovarian volumes were calculated using the prolate ellipsoid formula. The correlation coefficient between the ovarian volume measurements made by each examiner was 0.960. These results indicate that interobserver variation in ovarian volume measurements is extremely low as determined by transvaginal sonography.     

Four-dimensional sonographic assessment of fetal facial expression early in the third trimester.

OBJECTIVE: To evaluate the characteristic patterns of facial expression in fetuses aged from 28 to 34 weeks using 4-dimensional (4-D) ultrasonography. METHODS: The faces of 10 healthy fetuses aged from 28 to 34 weeks were recorded continuously for 15 min with a 4-D ultrasonographic machine performing up to 25 frames per second. The occurrence rates of blinking, mouthing, yawning, tongue expulsion, smiling, scowling, and sucking were evaluated. RESULTS: Mouthing was the most frequent facial expression (median, 6.5; range, 2-19) whereas the least frequent were scowling (median, 1; range, 0-9) and sucking (median, 1; range, 0-2). Mouthing was evident in all fetuses and significantly more frequent than any other movement (P<.05). Yawning (median, 3; range, 0-6), smiling (median, 2; range, 0-9), and blinking (median, 1.5; range, 0-6) were observed in most cases. Tongue expulsion (median, 1.5; range, 0-5), scowling, and sucking were each observed in 6 cases. CONCLUSION: 4-D sonography provides a means of evaluating fetal facial expression early in the third trimester. It may be a key to predicting fetal brain function and well-being and an important modality in future fetal neurophysiologic research.     

Transvaginal sonographic fetal axis determination in early second trimester

Objective  Correct prenatal determination of the fetal right/left axis is essential for the diagnosis of fetal malformations, in particular congenital heart anomalies. A reliable method of transabdominal echocardiographic assessment of the fetal situs in the late second trimester was established. We aimed to determine the validity of the transvaginal approach to assess fetal axis. Method  The study group consisted of 108 consecutive women in the second trimester of a singleton pregnancy, undergoing elective transvaginal anatomy scans. All had undergone previous transabdominal echocardiography to establish fetal axis. The same technique was used to assess the fetal axis during the transvaginal study, and the findings were compared. Results  There was total agreement in fetal axis determination between transabdominal and transvaginal scans in all cases. The accuracy of the transvaginal study was not affected by maternal obesity, fetal position or the presence of cardiac malformation (in one case). Conclusion  Transvaginal ultrasonography is the reliable and accurate means of determining the fetal axis. Both affiliations are affiliated with Sackler Faculty of Medicine, Tel Aviv University.     

First trimester fetal heart rate measurements by transvaginal ultrasound combined with pulsed Doppler: an evaluation of 1331 cases

The aim of this study is to present the cardiac activity measurements obtained from 1331 embryos and first trimester fetuses in whom the crown-rump length (CRL) measurements were between 2 and 60 mm, and to correlate the pattern of changes according to growth in body length, with an objective and reliable technique; transvaginal ultrasound combined with pulsed Doppler. Sonographic examinations were performed using a Combison 320-Kretz scanner with a 5–7.5 MHz vaginal probe with 240° scanning angle, combined with a 4.5 MHz pulsed Doppler. As the embryo grows, the mean heart rate increases sharply, from 106.8 ± 6.4 at a CRL of 2 mm to 178.3 ± 7.0 at a CRL of 23 mm; followed by a plateau and a slight decline thereafter. Statistical analysis of the body length and corresponding heart rate revealed a relationship with a correlation coefficient of 0.61 (P < 0.01), whereas relationship between CRL ≤ 23 and corresponding heart rate was striking with a correlation coefficient of 0.87 (P < 0.01).     

Four-dimensional sonographic assessment of inter-twin contact late in the first trimester

Objective

To evaluate the total number of inter-twin contacts between monochorionic diamniotic (MD) and dichorionic diamniotic (DD) twins using four-dimensional (4D) sonography late in the first trimester of pregnancy.

Method

Six MD and 8 DD pregnancies were studied for 30 minutes with 4D sonography at 10-11 and 12-13 weeks of gestation. A total of 10 types of inter-twin contact was evaluated.

Results

There was a significant difference in the total number of all contacts between MD and DD twins at the 10-11 weeks of gestation (P < 0.05). There was also a significant difference in the total number of contacts between 10-11 and 12-13 weeks of gestation in DD twins (P < 0.05).

Conclusion

Four-dimensional sonography provides a means of evaluating inter-twin contact in the first trimester of pregnancy and could be an accurate and reliable tool in studies of inter-twin behavior.     

Three-dimensional sonographic visualization of fetal skeleton in the second trimester of pregnancy

PURPOSE: To demonstrate the potential of using three-dimensional (3D) sonography to reveal anomalies of fetal skeleton. MATERIALS AND METHODS: Forty-two normal fetuses and 3 anencephalic fetuses from 14 to 27 weeks' gestation were studied with a specially developed abdominal 3D transducer (3.5 MHz). This imaging system provided conventional two-dimensional (2D) sonographic images and also generated within seconds high-quality 3D images in the surface and transparent mode with no need for an external workstation. RESULTS: Using this imaging system, we obtained 2D and 3D images of fetal skeleton (skull, scapula, spine, rib, humerus, ulna/radius, pelvis, femur, and tibia/fibula) at two gestational ages. The percentages of fetal skeletal visualization at less than 20 weeks of gestation using 3D sonography were 78-100%, whereas those with 2D sonography were all 100%. The percentages of skeletal structures revealed after 20 weeks' gestation using 3D sonography were 82-100%, whereas those with 2D sonography were all 100%. We found no significant differences in detection rates of the fetal skeleton between 2D and 3D sonography. However, 3D sonographic images generally provided a more comprehensive view of the fetal skeleton than did conventional 2D sonography. In 2 cases with anencephaly, 3D sonography clearly revealed the defect of cranium. CONCLUSION: The new 3D sonographic technology can generate within seconds high-quality 3D images of the fetal skeleton. The 3D technology seems to perform at least as well as conventional 2D sonography. Our results suggest that 3D sonography has the potential to supplement 2D sonography and might be useful in identifying malformations of the fetal skeleton and chromosomal abnormalities in utero.     

Reliability of transvaginal ultrasound in detecting first trimester pregnancy abnormalities

OBJECTIVE: To evaluate the reliability of transvaginal ultrasound (US) and human chorionic gonadotropin (hCG) levels in detecting early abnormalities and predicting outcome of pregnancy. PATIENTS: One hundred thirty-two patients were studied, of which 113 had an intrauterine pregnancy and 19 had an ectopic pregnancy (EP). RESULTS: In 78 with singleton normal pregnancies, US revealed a normal crown-rump length, heart motion, and hCG levels between 1,000 to 107,000 mIU/mL. Of 16 patients with small crown-rump length, heart motion present, and normal hCG levels, 6 aborted and 10 reached term. Thus, 6 of 84 (7.14%) singleton with fetal heart motion aborted. Thirteen with small crown-rump and absent heart motion also aborted. All 8 with an empty gestational sac aborted. In 8, transvaginal US detected four twins, two triplets, and two quadruplets, whereas hCG was not discriminative. Transvaginal US revealed an empty uterus in 19 patients with an EP, whereas serum hCG varied between 37 and 10,500 mIU/mL. CONCLUSION: A fetal crown-rump length compatible with gestational age and fetal heart motion seen by transvaginal US can predict a term pregnancy in greater than 90% of patients.     

Evaluation of fetal echogenic bowel in the second trimester.

Previous studies cite different possible etiologies for fetal echogenic bowel (FEB). The purpose of this study was to evaluate the possible etiologies for second-trimester FEB, and to provide clinical guidelines for evaluation of this finding. The study included 79 patients diagnosed with FEB in the second trimester. Fifteen cases (19%) were associated with maternal vaginal bleeding. Of these, 12 patients underwent amniocentesis, 9 of which had visible blood products in the amniotic fluid. Seven cases (8.9%) had associated severe malformation. Seven other cases (8.9%) were noted in multifetal pregnancies. Five fetuses (6.3%) had evidence of bowel obstruction or perforation not associated with cystic fibrosis (CF). Chromosomal aberrations were found in 5 fetuses (6.3%). Intrauterine infection with cytomegalovirus, herpes simplex virus, varicella-zoster virus, or parvovirus B-19 was documented in 5 patients (6.3%). Three cases (3.8%) were associated with subsequent unexplained stillbirth. Two fetuses (2.5%) were found to be affected by CF. Finally, in 30 cases (38%), no obvious reason for FEB was found. We conclude that the evaluation of second-trimester FEB should include targeted ultrasound for associated malformations, infectious studies, DNA analysis for CF mutations, amniocentesis for chromosomal analysis and evaluation of the amniotic fluid for degraded blood products, and an autopsy in cases of stillbirth. Even when no apparent reason is found, pregnancies should be considered at high risk for poor outcome.     

Imaging the fetal brain in the second and third trimesters using transvaginal sonography

High-frequency transvaginal probes were used at 20-40 weeks' gestation to develop a systematic examination of the fetal brain. Modeling the procedure after the standard neonatal neurosonographic examination, we attempted to obtain three coronal sections (anterior, midline, posterior) and two sagittal sections (midsagittal, right or left parasagittal). In 70 normal patients, all planes were imaged with a similar frequency (74-76%) except for the posterior coronal plane, which was imaged 59% of the time. Among the first 35 cases, 17% had a complete study, compared with 71% of the second 35 cases. Transvaginal sonography established or changed the diagnosis in five of the 13 cases with central nervous system or other abnormalities. We recommend that a complete fetal neurosonographic examination include transvaginal sonography to complement and enhance the transabdominal examination, especially for cases in which a fetal abnormality is suspected.     

Reference values of fetal orbital measurements by transvaginal scan in early pregnancy

OBJECTIVE: To construct reference ranges of orbital diameters, measured in early pregnancy by transvaginal sonography. METHODS: The study group consisted of 2717 fetuses of pregnant women referred to our center and examined by transvaginal ultrasound between 11-16 week's gestation. Nomograms with confidence intervals (5th and 95th percentile) for each orbital measurement (orbital diameter, interocular and binocular distance) versus gestational age were produced. RESULTS: The orbital measurements increased in a linear fashion throughout early pregnancy with a good correlation with gestational age. CONCLUSION: Transvaginal sonography is able to visualize and measure orbital diameters with accuracy in early pregnancy; reference ranges were developed that can be used to evaluate normal orbital development and can be helpful in the detection of syndromes with orbital growth defects and other associated fetal anomalies.     

Acceptability of early transvaginal or abdominal sonography in the first half of pregnancy

OBJECTIVE: To evaluate the acceptability of early transvaginal sonography by pregnant patients. METHODS: A questionnaire was completed by 246 patients and the resulting data were analysed. RESULTS: The incidence of discomfort was higher for the transabdominal than for the transvaginal route. Moreover, the transvaginal approach in early pregnancy, when compared with other transvaginal sonographic examinations was described as more satisfactory in 95% of cases. CONCLUSIONS: Transvaginal sonography in early pregnancy is better tolerated than transabdominal sonography.     

阴道超声检查对子宫内膜癌术前分期诊断的帮助价值

目的 探讨经阴道超声检查诊断子宫内膜癌的价值。方法 总结分析经阴道超声检查对30例Ⅰ期子宫内膜癌患者肌层浸润程度的诊断结果。结果 经阴道超声检查子宫内膜癌肌层浸润的准确率为86．7％。结论 经阴道超声检查能较准确地诊断出肿瘤对肌层的浸润程度，可作为子宫内膜癌患者的首选影像学检查方法。为临床选择恰当治疗方案提供有效依据。     

Intrapartum sonography for fetal head asynclitism and transverse position: sonographic signs and comparison of diagnostic performance between transvaginal and digital examination

Objective: The primary goal of this study was to determine the ultrasonographic signs of asynclitic and transverse head positioning. In addition, we compared the performance of intrapartum ultrasound to vaginal digital examination. Material & Methods: 150 women were evaluated by 2D transabdominal and translabial ultrasound (US) to detect the asynclitic and deep transverse positions. Transvaginal sterile digital examinations were performed immediately after each intrapartum US assessments, the examinations were repeated at intervals of 45–90 minutes. Examiners were blinded to each other’s findings (clinical or sonographic). Data were reviewed and analyzed by an independent reviewer. Results: The efficacy of digital examination was significantly lower than US evaluation for the detection of either transverse position or asynclitism. The most frequent transverse position was the left one, while the most frequent asynclitism was the anterior one. Conclusions: Digital pelvic examination for detection of fetal head transverse position during labor is inferior to US, especially in the deep transverse positioning, where caput succedaneum occurs and reduces the diagnostic accuracy of vaginal digital examination. The US examination leads to early detection of persistent transverse position allowing for earlier timing and optimal technique for the operative vaginal delivery. We describe two signs for diagnosing asynclitism. The “squint sign” and the “sunset of thalamus and cerebellum signs” are two simple US signs allowing detection of anterior and posterior asynclitism.