Hsi-Yao Chen

Altered placental syncytin and its receptor ASCT2 expression in placental development and pre-eclampsia

Objective  To investigate the alterations of syncytin, a fusogenic membrane protein involved in syncytiotrophoblastic layer formation, and its receptor ASCT2 expression in placental development and pre‐eclampsia.

observation of cesarean section scar by transvaginal ultrasonography

Transvaginal ultrasonography, with its higher frequency and proximity to the pelvic structures has offered us a powerful tool for observing the uterine scar of a previous Cesarean section. We have examined 87 previous Cesarean section scars by transvaginal ultrasonography. Forty cases (group A) were in the third trimester. Fifty-two percent of this group showed normal patterns. In the remaining cases, thickening of the previous incision site was the most common finding. Also, thinning, ballooning and wedge defect were noted. Forty-seven cases (group B) were examined within 3 months (group B1) or after 3 months of Cesarean section (group B2). Similarly half of them showed normal patterns. In the remaining cases, wedge defect was the most common finding. The others were outward or inward protrusions, hematoma formation and inward retraction. An evaluation of the previous section scar, preferably by high resolution transvaginal ultrasonography is highly recommended in considering a trial of labor after previous Cesarean deliveries.

Percutaneous ultrasound- guided fetal blood sampling in the management of nonimmune hydrops fetalis

Nonimmune hydrops fetalis can be caused by fetal chromosomal, hematologic, cardiac, or infectious conditions. A fetal blood sample obtained from percutaneous ultrasound-guided fetal blood sampling can offer vital information about the underlying cause of nonimmune hydrops fetalis, and perinatal management can be planned accordingly. Ten cases of nonimmune hydrops fetalis were investigated with percutaneous ultrasound-guided fetal blood sampling and subsequent fetal blood analysis. Nine were proved to be Barts hemoglobin hydrops fetalis, with 78.2% to 99% of Barts hemoglobin in the fetal blood. Terminations of pregnancy were undertaken immediately, resulting in a lowered maternal morbidity rate. Free cord loops or an intra-abdominal portion of the dilated umbilical vein can be used for percutaneous fetal blood sampling in nonimmune hydrops fetalis when the placental cord insertion is difficult to visualize. Percutaneous ultrasound-guided fetal blood sampling and subsequent fetal blood analysis will eventually play a key role in the management of the puzzling nonimmune hydrops fetalis if the safety of ultrasound-guided fetal blood sampling can be verified by further clinical studies.

Correlation of Uterine Hemodynamics With Chemotherapy Response in Gestational Trophoblastic Tumors

Objective: To assess the uterine hemodynamics in gestational trophoblastic tumors and to correlate them with response to chemotherapy. Methods: Using transvaginal color Doppler ultrasound, we measured the peak systolic velocity and the resistance index (RI) of the uterine arteries in 23 women with gestational trophoblastic tumors before each course of chemotherapy. Fifty‐five nonpregnant women and another 15 women who had uneventful molar evacuation were enrolled as controls. Two‐tailed Student t test was used for statistical analysis. Results: A hyperdynamic uterine circulation was noticed at diagnosis in all gestational trophoblastic tumors, manifested as higher peak systolic velocity (mean ± standard deviation 57.5 ± 20.4 cm/second) of the uterine arteries compared to nonpregnant (28.3 ± 3.41 cm/second; P < .0001) and uneventful post‐mole uteri (26.8 ± 3.08 cm/second; P < .0001). The RI values of the uterine arteries in gestational trophoblastic tumors at diagnosis ranged from 0.21‐0.80. However, the mean value (0.56 ± 0.19) was lower than those of nonpregnant (0.80 ± 0.05; P < .0001) and post‐mole uteri (0.75 ± 0.06; P < .0001). A higher pre‐treatment uterine artery RI (mean 0.71 ± 0.09) was noted in ten patients with gestational trophoblastic tumors requiring fewer than five courses of chemotherapy, compared with the mean in 13 patients requiring longer courses of treatment (0.47 ± 0.14; P < .0001). There was a marked decrease of peak systolic velocity during the first three courses of treatment in the former group (54.2 to 23.6 cm/second; P < .001), in contrast to no change in the latter group (60.1 to 60.5 cm/second). Conclusion: Uterine hemodynamic characteristics assessed by color Doppler ultrasound might predict and monitor the response to chemotherapy in gestational trophoblastic tumors. (Obstet Gynecol 1994;83:1021‐5)

Antenatal diagnosis of vasa previa by color-flow mapping

Although vasa previa is certainly not common, it can lead to catastrophic consequences with high fetal morbidity and mortality. Literature reviews all conclude that the diagnosis of vasa previa is difficult and is rarely made antenatally. Often the diagnosis is made only after the delivery of a severely jeopardized or dead infant. Thus, obstetricians should always be on the lookout for it and use all possible tools to detect it antenatally. In this report, we describe the use of colorflow mapping for antenatal diagnosis of vasa previa. We make recommendations for situations in which color-flow mapping is helpful in antenatal diagnosis of this rare but dangerous obstetric entity.

Antenatal fetal blood flow in the descending aorta and in the umbilical vein and their ratio in normal pregnancy

One hundred and sixty sequential measurements of umbilical vein blood flow (UVBF) and descending aorta blood flow (DABF) in normal fetuses were performed in utero by the duplex real-time ultrasound and pulsed Doppler technique. Throughout pregnancy from 26 to 41 weeks the blood flow velocity of the umbilical vein (UV) and the descending aorta (DA) remained relatively constant, while the diameter of UV and DA, UVBF and DABF increased with advancing gestational age. Moreover, the UVBF-to-DABF ratio was nearly constant, with a mean value of 64% from 26 weeks onwards. The DABF-to-abdominal area (DABF-to-AA) ratio was constant throughout pregnancy, with a mean value of 7.0 ml/min/cm2. We call these two constants the umbilical-aortic index and descending-aortic index. These relationships may be of help in the diagnosis of intrauterine growth retardation and other fetal disorders.

Delayed maternal death after perimortem cesarean section

We report a case of perimortem cesarean section performed on a multigravida with congestive heart failure. This patient had a past history of repeated episodes of acute myocarditis and this time, congestive heart failure attacked her at the 36th week of gestation. The maternal condition deteriorated rapidly with frequent attacks of ventricular fibrillation and cardiac arrest, which gradually became unresponsive to active cardio‐pulmonary resuscitation (CPR). The fetal condition also worsened accordingly. Cesarean section was therefore performed and a 2590 gm depressed female baby was delivered in less than one minute after skin incision and about twenty‐seven minutes after the maternal condition became extremely unstable. The Apgar scores were 1 at one min, 4 at five min and 6 at ten min. The mother improved soon after delivery of the fetus and her consciousness returned. However, her condition deteriorated again and she died four hours after operation. The fetus survived and follow‐up 21 months after delivery was normal.

WS14‐06Implemented three‐dimensional power Doppler for evaluation of fetal and placental circulation: implications for clinical management

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