yolk sac, fetal heart, in the first trimester

OBJECTIVES: To investigate embryonic heart rate (EHR) and yolk sac diameter (YSD) during the first trimester and their role as prognostic markers of first trimester pregnancy outcome. STUDY DESIGN: Prospective cohort study involving 219 women conducted in the 4th Academic Department of Obstetrics and Gynaecology, Aristotle University of Thessaloniki, Greece. Gestational age (GA) was determined ultrasonographically based on gestational sac diameter and crown-rump length...

The objective of this study was to determine if very early ultrasonographic measurements obtained from human and baboon are comparable. For this purpose, the gestational, amniotic and yolk sacs, embryonic crown rump length (CRL) and heart rate were measured ultrasonographically between 35 and 47 days from the mean day of a three-day mating period in baboons (n=18) and between 42 to 58 days from fertilization as calculated from the CRL measurements in human pregnancies (n=82). Ultrasonographic measurements from both species were then plotted in the same graph using Carnegie stages of embryonic development as the independent variable to allow for visual comparisons...

A case of umbilical cord cyst was identified via 2-dimensional and 3-dimensional sonographic examination at 8 weeks' menstrual age. The cyst was solitary, measuring 18.0 mm, and it was located close to the placental insertion on the umbilical cord. The gestational sac and yolk sac diameters and the fetal heart rate were within normal ranges for menstrual age. Follow-up 3-Dimensional sonographic examination in the second trimester showed complete resolution of the cyst. Amniocentesis revealed a normal karyotype, and a normal infant was delivered at term...

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...

OBJECTIVES: The aim of the research was evaluation of the clinical usefulness of chosen ultrasonographic morphological parameters of the yolk sac in the first trimester of unifetal pregnancies. MATERIAL AND METHOD: Analysis has been done on 391 cases of unifetal pregnancies in the first trimester. Parameters of ultrasonographic evaluation: diameter, appearance and size of yolk sac, biometrics and fetal anatomy, confirmation of heart beating. CONCLUSIONS: The yolk sac should be observed in the fifth week or when its biggest size equals to 10 mm in a normal pregnancy...

OBJECTIVE: To evaluate the relative prognostic value of ultrasound findings during the first-trimester scan by univariate and logistic regression analysis in a group of asymptomatic women. STUDY DESIGN: A total of 125 asymptomatic pregnant women with a singleton conceptus, concordance between menstrual age and crown-rump length, and documented fetal activity, 25 for each gestational age between 6 and 10 weeks, were enrolled in the study and underwent a transvaginal sonographic examination...

OBJECTIVES: To determine the relationship between the yolk sac and umbilicoplacental circulations during the first trimester of pregnancy. DESIGN: Sixteen normal singleton pregnancies were included in this longitudinal study. Transvaginal ultrasonography with color and pulsed Doppler was performed at 5+, 7+, 8+ and 10+ gestational weeks. Fetal heart rate and blood velocity waveforms of yolk sac, umbilical and chorionic arteries were obtained. RESULTS: The detection rate of arterial blood flow in the yolk sac increased significantly from 5+ (2/16) to 7+ gestational weeks (12/16)...

A cystic mass of the umbilical cord was identified by transvaginal sonography in 10 first trimester pregnancies at a mean gestational age of 8 weeks 4 days (range, 8 weeks 1 day to 9 weeks 3 days) and at a mean crown-rump length of 20.5 mm (range, 15 to 25 mm). The cyst was solitary in all cases, the mean diameter was 4.6 mm (range, 3 to 6 mm), and the location was closer to the fetal insertion in two cases, in the middle of the cord in seven cases, and closer to the placental insertion in one case. Gestational sac and yolk sac diameters as well as the fetal heart rate were within normal ranges for gestational age in all cases...

One hundred thirty two patients at an early gestational age were monitored every other day to establish beta hCG levels at which the gestational sac, the yolk sac and fetal heart motion can be sonographically detected. These structures were observed at significantly lower beta hCG levels by means of the vaginal probe in comparison with the abdominal one. In normal pregnancy a gestational sac of 1-3 mm was detected at a mean hCG level of 1150 UI/l (range 800-1500); the yolk sac was detected at a mean hCG level of 6000 UI/l (range 4500-7500); fetal hart motion was visible at a mean hCG level of 10,425 UI/l (range 8650-12,200)...

Transvaginal echography was used to examine 78 asymptomatic patients at their first ultrasound examination, at risk for repeated abortion in the first trimester of pregnancy. The purpose of this study was to evidentiate, in the initial stages of pregnancy, reliable echographical evidence that can be used as a prognostic value on the future course of pregnancy. The normal sequential appearance of the yolk sac of the embryo and of the fetal heart activity have proved to be reassuring criteria on the course of pregnancy in 87% of the cases...

Ultrasonographic morphometric measurements were obtained with transvaginal ultrasonography from 121 patients with first trimester singleton pregnancies. Amniotic and gestational sac diameters, fetal heart area, and fetal length increased in a linear rate relative to crown-rump length, whereas the amniotic and gestational sac volumes increased at an exponential rate. The yolk sac exhibited a biphasic growth pattern with a peak at a crown-rump length of 3.5 cm. The ratio of crown-rump length to anteroposterior dimension increased over the first trimester, suggesting less curvature in older fetuses...

Seven pregnancies with positive fetal heart activity and low or very low serum beta-human chorionic gonadotropin (beta-hCG) levels were investigated. The gestational age by dates was between 6 weeks 3 days and 8 weeks 4 days at the time of the first ultrasound scan and beta-hCG ranged between 282 and 10,000 mIU/ml of the Second International Standard. The crown-rump lengths ranged between 6 and 13 mm and heart activity was always detected. Four cases were scanned because beta-hCG was lower than that expected for the gestational age; in these cases the yolk sac was present but the gestational sacs were small, with a trophoblastic ring that looked thin and subjectively seemed abnormal...

Using a high-resolution real-time arc sector scanner, fetal cardiac activity was detected in ten normal intrauterine pregnancies, including one triplet gestation, between 41 and 43 days of gestation. Fetal heart rates ranged from 96 to 120 beats/min (mean 110) and were detected contiguous with the yolk sac as a tiny blinking, flashing, and/or rocking echo with a regular rhythm. The mean gestational sac fluid diameters ranged from 8 to 16 mm and the crown-rump lengths, when measurable, were less than 4 mm. The demonstration of early fetal cardiac activity in utero reduces parental anxiety and indicates a favorable prognosis in patients with threatened abortion, and virtually excludes the diagnosis of ectopic pregnancy...

A total of 97 transvaginal scans were performed from 4 to 12 weeks' gestation in normal and accurately dated gestations. The sequential appearance of six structures were examined: (1) the gestational sac only was present during week 4; (2) the yolk sac appeared in week 5; (3) the fetal pole with detectable heart motion was first seen in week 6; (4) the single unpartitioned ventricle in the brain marked week 7; (5) the falx cerebri appeared during week 9; and (6) the appearance and the disappearance of the physiologic midgut herniation were seen in week 8 and week 11, respectively...

Transvaginal sonography (TVS) is the procedure of choice in evaluating the viability of embryos early in pregnancy. However, viability based on TVS can be assessed more accurately when the exact gestational age from the last menstrual period is known or when the findings are correlated with beta human chorionic gonadotropin (HCG) levels. No large series has been reported with correlative data between early pregnancy findings, HCG, and gestational age. We performed 75 transvaginal examinations in 53 patients with proved normal pregnancy in the fifth through seventh weeks of gestation...

To determine the embryonic size at which cardiac activity is always seen in a normal early pregnancy, 398 endovaginal sonograms were evaluated in which the gestational sac contained a yolk sac and/or embryo of less than or equal to 12 mm in crown-rump length (CRL). In the 99 sonograms in which there was a yolk sac but no identifiable embryo, cardiac activity was absent in 75; 58 of these pregnancies progressed normally. Of the 299 sonograms where there was an identifiable embryo with CRL less than or equal to 12 mm, cardiac activity was absent in 31; 29 of these were proven to be failed pregnancies...

Vaginal sonography and determination of serum hCG levels were carried out in 22 healthy pregnant women every 2 to 4 days after the first positive pregnancy test until a living fetus was observed. Gestational age was calculated from the day of ovulation, assessed by LH surge or hCG administration, plus 14 days. A gestational sac of 1-3 mm was detected at a mean (SEM) of 31.2 (0.2) days of gestation (range 30-33 days). The corresponding mean hCG level was 730 iu/l (30) and the range 467-935 iu/l (International Reference Preparation)...

The authors reviewed the endovaginal ultrasonographic (US) findings for 96 patients with embryos with crown-rump lengths of less than 5.0 mm. Of the 71 patients with adequate follow-up, initial endovaginal US demonstrated cardiac activity in 46 embryos and no cardiac activity in 25. Initial endovaginal US failed to demonstrate cardiac activity in five of 40 normal embryos, three with crown-rump lengths of less than 2.0 mm and two, between 2.0 and 3.9 mm. Endovaginal US identified cardiac activity in all 12 normal embryos with crown-rump lengths of 4...

A cross-sectional transvaginal ultrasound study was conducted in 137 normal pregnancies with gestational ages ranging from 5-12 weeks. Several biometric measurements were obtained throughout pregnancy, including the three diameters of the gestational sac, the crown-rump length, and the yolk sac. In addition, the appearance of the embryo heartbeat and embryo body movements were evaluated. Linear relationships were found between the mean gestational sac diameters and gestational age (r = 0.911; P less than .00001) and between mean gestational sac growth and crown-rump length growth (r = 0...

To study the development of the size of various gestational parameters in the first trimester, the vaginal sonographic measurements in 259 normal intrauterine singleton pregnancies with reliable dates between 4 and 13 complete weeks menstrual age were analysed. Growth curves of the mean chorionic cavity diameter, the maximum thickness of the trophoblast, the yolk sac diameter, the crown-rump length, the mean amniotic cavity diameter, the biparietal diameter, the transverse abdominal diameter and the femur length as well as the course of the embryonic heart rate together with their 90% confidence limits, respectively, are shown...