Early pregnancy assessment with transvaginal ultrasound scanning

Department of Obstetrics and Gynaecology, McMaster University, Hamilton, Ont.
Canadian Medical Association Journal (Impact Factor: 5.96). 03/1991; 144(4):441-6. DOI: 10.1097/00006254-199110000-00004
Source: PubMed


To establish normal parameters in early pregnancy through transvaginal ultrasonography so that gestational age can be determined and to correlate the sonographic findings with serum human chorionic gonadotropin (hCG) levels calibrated against the first international reference preparation standard.
Infertility clinic.
Thirty-five women with normal intrauterine pregnancy.
Serial measurement of the serum hCG level and the diameter of the gestational sac through transvaginal ultrasonography.
The gestational sac could not be visualized when the hCG level was less than 1100 IU/L. The average growth rate of the sac was 0.9 mm/d. The threshold values for sac diameter, serum hCG level and gestational age below which the yolk sac was not visible were 3.7 mm, 1900 IU/L and 36 days respectively; the corresponding values above which the yolk sac was always visible were 6.7 mm, 5800 IU/L and 40 days. The threshold values below which cardiac activity was not visible were 8.3 mm, 9200 IU/L and 41 days respectively, and the corresponding values above which cardiac activity was always visible were 14.0 mm, 24,000 IU/L and 46 days. The mean gestational ages and the 95% confidence and prediction intervals were tabulated so that measurement of the gestational sac diameter could be used to estimate gestational age early in normal pregnancy.
Transvaginal ultrasonography enables detection of an intrauterine sac and reliable estimation of gestational age on the basis of sac dimensions before an embryo can be seen.

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    • "Several anatomical parameters are useful in the assessment of gestational age. In early pregnancy, we use mean sac diameter(MSD) (Fossum et al (1988), Bree et al (1989), Daya et al (1991), and crown rump length (CRL)4 to assess gestational age. In second and third trimesters, we use four main anatomic parameters viabiparietal diameter5, head circumference, abdominal circumference Hadlock et al (1982), and femur length. "
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    ABSTRACT: Correct assessment of gestational age is a cornerstone of management of any obstetric case. Several anatomical parameters are useful in the assessment of gestational age. The ultimate aim of this study is to determine the fetal gestational age through the measurement of the foot(foot length) and to determine the accuracy of fetal foot length in estimating gestational age. Methods: There were one hundred pregnant ladies in 2nd and 3rd trimesters had been selected randomly in different medical centers and hospitals in Khartoum State. They were scanned with ultrasound using the international protocols and guidelines of obstetric ultrasonography. Statistical analysis using regression equation and correlation was obtained. Results: There was a strong correlation between fetal foot length and gestaional age. Conclusion: Fetal foot length is a reliable parameter for use in the assessment of gestational age and is particularly useful when other parameters do not accurately predict gestational age. The study derived an important equation to estimate the GA, the GA= 82.411+2.191FtL. [Moawia Gameraddin, Suliman Salih, Mohamed yousef. Evaluation of Gestational Age with Fetal Foot Length Using Ultrasonography. J Am Sci 2014;10(1):5-7]. (ISSN:
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    ABSTRACT: Pregnancy can be detected early using transvaginal ultrasonography and human chorionic gonadotropin (hCG) measurements. The purpose of this study was to correlate serum hCG levels with transvaginal gestational sac measurements. The mean sac diameter (MSD) and gestational sac diameter (GSD) were calculated as the mean and cube root of the product, respectively, of three sac dimensions taken at right angles. A nonlinear relationship between hCG (natural logarithm) and MSD and GSD was observed. The data were best fitted by a second order polynomial regression model (r2 = 0.98), thereby establishing normal hCG levels for various gestational sac dimensions in early pregnancy.
    Journal of Clinical Ultrasound 03/1991; 19(3):139-42. DOI:10.1002/jcu.1870190303 · 0.69 Impact Factor
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    ABSTRACT: Recent reports have indicated that identification of the yolk sac should precede the detection of the embryo in a normal first-trimester sonographic examination and that failure to visualize a yolk sac strongly suggests an abnormal intrauterine pregnancy. A first-trimester prospective study was performed in 163 normal and 49 abnormal consecutive singleton gestations. All women were examined both abdominally and transvaginally, with pregnancy outcome determined by delivery of a normal infant or a spontaneous abortion. The yolk sac was analyzed in all patients in whom an embryo was not identified (n = 76). When the yolk sac was identified, the following was found: by the abdominal approach with the mean sac diameter (MSD) less than 27 mm (n = 15), nine gestations were normal and six were abnormal, and by the transvaginal approach with the MSD less than 18 mm (n = 13), seven gestations were normal and six were abnormal. The presence of a yolk sac was not consistently predictive of a normal early pregnancy. When the yolk sac was also not identified, the following was found: abdominally with the MSD less than 27 mm (n = 41), 19 gestations were normal and 22 were abnormal, and transvaginally with the MSD less than 18 mm (n = 11), six gestations were normal and five were abnormal. Absence of the yolk sac was not consistently predictive of a spontaneous abortion. When using the MSD range (20-27 mm abdominally and 7-16 mm transvaginally), over which the yolk sac but not the embryo should be identified sonographically, the yolk sac was again not consistently visualized. On abdominal sonograms, the yolk sac was present and absent in three and 10 patients, respectively, for both normal and abnormal pregnancies. On transvaginal sonograms, the yolk sac was present and absent in seven and five normal gestations and in six and four abnormal gestations, respectively. The results of this study suggest that detection of the yolk sac in the first trimester is not an early predictor of pregnancy outcome.
    American Journal of Roentgenology 05/1992; 158(4):843-7. DOI:10.2214/ajr.158.4.1546604 · 2.73 Impact Factor
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