저자들은 1976년 1월부터 만 6개월 동안 가톨릭의과대학 부속 성모병원 산부인과에 내원한 환자중 임신 5주에서 21주까지의 산모 67명에 대하여 81회의 초음파 단층촬영을 시행하여 다음과 같은 결론을 얻었다. 1) 태아상은 임신 6주의 9예중 3예(33.3%), 7주의 8예중 5예(62.5%), 그리고 8주 이후에는 모든 예(100.0%)에서 관찰되었다. 2) 자궁의 종경은 임신 5주부터 21주까지 7.3cm에서 18.9cm으로 증가하여 희귀직선은 0.71 wks+3.14 (r=0.96, P<0.01)이었고, 최대전후경은 동일기간 동안 4.2cm에서 10.0cm으로 증가하였으며 희귀직선은 0.27 wks+3.53 (r=0.83, P<0.01)이었다. 3) 태낭은 임신 5주부터 12주까지 1.4cm에서 5.3cm으로 증가하였으며 희귀직선은 0.53 wks-1.41 (r=0.92, P<0.01)이었다. 4) 아두대횡경치는 임신 11주부터 21주까지 1.8cm에서 4.6cm으로 증가하였고 희귀직선은 0.30 wks-1.80 (r=0.53, P<0.01)이었다. 임신 전반기에 시행한 초음파 단층촬영의 측정치들이 이 희귀직선들과 일치하면 정상적으로 진행되는 임신으로 간주할 수 있다.

Gestational assessment in early stage has always been a challenge to the obstetricans. It is not always possible to draw definitive conclusions of the basis of uterine size, and positive immunological pregnancy tests are not always indicative of a normally progressing pregnancy because of hCG excretion continues as long as there is even a little trophoblast tissue left in the uterus. Roentgenological studies are reliable only around the 20th week of gestation with limited diagnostic and prognostic potential. Ultrasound have, in contrast, been shown to be capable of distinguishing the normally progressing pregnancies from abnormal cases after 5th week of pregnancy. This study consisted of sixty seven presumably normal gravidas whose last menstrual period was known precisely and who were subjected to sonographic analysis at varying intervals from the fifth to the twenty first week of amenorrhea at the Dept. of Obst. & Gynecol., Catholic Medical College from 1st of Jan. 1976 to 31st of July 1976. Some were examined serially at various intervals during early pregnancy. Others had only one set of observations. The B-scan was employed for all examinations. The results were as follows; 1. In the 5 weeks and 3 days of pregnancy a small "white ring" can visualized as the earliest sign of detection for gestation sac, and by the 6 weeks fetal echoes were clearly visible within the gestation sac. Between the 11th-12th week the gestation sac and the fetal head were appeared. There was disappeared the gestation sac from the 13th weeks. 2. Fetal echoes were visible in the 6th week of pregnancy in 33.3% of normal pregnancies (n=9), in the 7th week in 62.5% (n=8) and from the 8th week onward in 100% of cases. 3. Although the number of observations in each instance is not great, the growth of the uterus, the gestational sac, and the fetal head all appear to bear a linear correlation to the duration of pregnancy. a) From the 5th to the 21st week, the regression equation obtained for longitudinal growth of the uterus was y=0.71 wk