Transvaginal assessment of fetal anatomy at 11 to 16 weeks of gestation inrelation to fetal position

Objective: To investigate the ability of the high-frequency transvaginal sc anning technique to assess embryo-fetal anatomy in early pregnancy in relat ion to fetal position and in comparison with transabdominal scan. Methods: A study population of 1,402 pregnant women were examined by transvaginal ul trasonography performed at 10(+1) to 16(+0) weeks of pregnancy, At 14(+1) t o 16(+0) weeks of gestation, an ultrasonographic examination was performed in 247 pregnant women by transvaginal and transabdominal route. The criteri a necessary for an adequate visualization of fetal organs and structures we re met. Results: The visualization rate of complete fetal anatomy increased with increase in menstrual age and fetal position affected this possibilit y. A detailed brain anatomy was more easily viewed with the fetus in the ce phalic or transverse position than in the breech position, whereas the thor acic and abdominal anatomy were viewed more easily with the transverse posi tion compared to the cephalic or breech position. Complete surveys of fetal anatomy were possible in 50% and 62% of women with transabdominal scan and in 85% and 85% with transvaginal one at 15 and 16 weeks' gestation, respec tively (p < 0.001). Conclusion: A detailed assessment of fetal structures w as possible in most cases at 13 weeks of gestation. Fetal position can infl uence this capability. At 14(+1) to 15(+0) weeks' gestation more anatomical surveys were completed with a transvaginal scan compared to a transabdomin al one and this was influenced by fetal position. Copyright (C) 2000 S. Kar ger AG, Basel.