Assessment of trophoblastic flow in abnormal first trimester intrauterine pregnancy.
Background: The use of color Doppler sonography in assessing feto-maternal circulation during pregnancy has recently been advocated. However, studies of evaluation of trophoblastic flow in the first trimester of pregnancy, with color Doppler sonography, are rare. The objects of this study were to assess the trophoblastic flow in first trimester pregnancy failure by using transvaginal color Doppler sonography, and attempted to elucidate the pathophysiology of early feto-maternal circulation.
Methods: One hundred and five cases of first trimester intrauterine pregnancy were enrolled in this study, including 34 cases of blighted ova, 50 missed abortions and 21 normal pregnancies. All patients received transvaginal sonography (Acuson 128, 5MHz). First, color Doppler was mapped and then trophoblastic flow (TBF) was detected and the resistance index (RI) was calculated. Main uterine artery (UA) flow was measured in the later part of this study. Serial sonographic examinations with serum beta-human chorionic gonadotropin (beta-hCG) levels were obtained to confirm a diagnosis of pregnancy failure. Discrepancy in gestational age calculated by the last menstrual period and by sonar measurement was recorded for analysis. The aborted tissues were submitted for karyotyping from six cases of normal pregnancy, 11 cases of blighted ovum and 22 cases of missed abortion.
Results: Preliminary result showed TBF can be detected at as early as the fifth week of gestation. The RIs of TBF and UA seemed to decrease; however, serum beta-hCG levels increased as gestational age advanced in normal pregnancies. This change was not shown in the abnormal groups. No significant difference in the RI of TBF or UA flow was noted between normal and abnormal pregnancies. Also the result of karyotyping did not correlate well with the RIs of TBF and UA, and serum beta-hCG levels.
Conclusions: The assessment of feto-maternal circulation in early pregnancy does provide information on the physiology of early normal placentation, but not of the early pregnancy failure. Limited case numbers and different time intervals between fetal demise and sonographic diagnosis may play roles in the above findings.