S. Sirichotiyakul

Transvaginal ultrasound in threatened abortions with empty gestational sacs

Objective: To determine whether transvaginal ultrasound criteria alone can distinguish viable from non‐viable gestational sacs at a single examination. Method: A prospective descriptive study was undertaken and analysis performed on 211 pregnancies complicated by threatened abortion and empty gestation sacs diagnosed by transvaginal ultrasound. The main outcome measure was the final diagnosis of viable or non‐viable gestation on subsequent transvaginal sonography. Results: The study shows that a single transvaginal ultrasound examination is useful in differentiating viable from non‐viable gestation sacs. The mean sac diameter (MSD) was found to be the most useful criterion for determining non‐viability. An MSD of ≥ 17 mm that lacked an embryo and an MSD of ≥ 13 mm without visible yolk sac were reliable predictors of non‐viable gestation sacs at a single examination with 100% specificity and 100% positive predictive value. An MSD ≥ 13 mm without visible yolk sac was the most sensitive criterion. Using MSD criteria, 73% of non‐viable gestations could be reliably identified without any false‐positive diagnoses. Deformed shape, low position and thin decidual reaction are strong indicators of non‐viable gestations but are not 100% accurate. There is still a significant proportion of empty sacs, where no accurate distinction between viable and non‐viable can be made according to one criterion at a single examination and in these cases serial examinations should be carried out before any active management is advocated. Conclusion: In most cases, transvaginal sonographic criteria alone can distinguish viable from non‐viable empty gestational sacs at a single examination.

Erythrocyte osmotic fragility test for screening of alpha-thalassemia-1 and beta-thalassemia trait in pregnancy

Objectives: To evaluate the sensitivity and specificity of osmotic fragility test (OFT) as a screening test in predicting the severe thalassemia trait (α‐thalassemia‐1 & β‐thalassemia). Methods: A descriptive analysis and diagnostic test of non‐anemic pregnant women attending antenatal care clinic, Maharaj Nakorn Chiang Mai, during April, and July 2002 was made. Blood samples were collected from 446 singleton pregnancies with no obvious medical complication such as iron deficiency anemia. OFT was performed in the same day, using 0.45% glycerin saline solution and the cut‐off value of less than 60% was used for an abnormal test. Quantitative HbA2 test and PCR (SEA type) were done as a gold standard to confirm the diagnosis of β‐thalassemia trait and α‐thalassemia‐1 trait, respectively. Results: The main outcome measures were sensitivity, specificity, positive and negative predictive value of OFT. If the OFT cut‐off value of less than 60% was considered positive, the test had a sensitivity, specificity, positive and negative predictive value of 97.6%, 72.9%, 33.6%, and 99.5%, respectively. Conclusion: OFT has high sensitivity in detection of α‐thalassemia‐1 trait or β‐thalassemia trait and due to its simplicity with very low cost it may, therefore, be considered as a screening test in a wide population.

Prenatal diagnosis of thrombocytopenia-absent-radius (TAR) syndrome.

The prenatal diagnosis of thrombocytopenia–absent‐radius (TAR) syndrome using ultrasound and cordocentesis in the 16th week of gestation is established. The sonographic findings detected in this case included bilateral absence of the radius and club hands with normal thumbs and metacarpals. Because of a high index of suspicion for the syndrome, cordocentesis for fetal blood analysis was performed. Thrombocytopenia, with a platelet count of 14 000/mm3, was identified. The pregnancy was electively terminated and subsequent findings confirmed the sonographic diagnosis. This report, to our knowledge, is one of a very limited number of cases published in the literature, in which the prenatal diagnosis of TAR syndrome was made.

Sonographic features of trisomy 13 at midpregnancy

Objectives: To evaluate the sonographic characteristics, at 16–22 weeks of gestation, of fetuses later diagnosed with trisomy 13. Methods: This descriptive analysis of a case series was conducted from June 1989 to May 2001 at the Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Thailand. Women with abnormal sonographic findings at midpregnancy (16–22 weeks of gestation) underwent amniocentesis or cordocentesis for karyotyping, and the inclusion criterion was proven trisomy 13. Results: Indications for sonographic examination at midpregnancy were a genetic risk, large‐ or small‐for‐date fetus, and other suspected anomalies. Fifteen fetuses were later diagnosed with trisomy 13. In all of these cases there was at least one abnormal sonographic finding. In only one case did the fetus show no structural abnormality (at 17 weeks), but polyhydramnios and fetal growth restriction were observed. Common sonographic findings included holoprosencephaly with associated facial anomalies, and abnormal feet and/or hands, especially polydactyly. Non‐structural abnormal findings such as polyhydramnios or fetal growth restriction were seen in less than one third of the fetuses. Conclusions: Nearly all the fetuses with trisomy 13 had sonographic characteristics of abnormalities at midpregnancy although common findings had often not yet appeared or the findings were low‐sensitive. Detailed ultrasound at midpregnancy could effectively screen for further genetic testing pregnancies at risk for trisomy 13.

Prenatal sonographic diagnosis of cardiac hemangioma with postnatal spontaneous regression

A 23-year-old pregnant woman, gravida 1 para 0, underwent ultrasound examination at 31 weeks’ gestation on account of antepartum hemorrhage. Ultrasound revealed normal fetal biometry, no placenta previa and normal amniotic fluid volume. On fetal echocardiography there was a slightly increased cardiothoracic ratio (0.6) and a slight left-axis deviation and pericardial effusion on the four-chamber view. In addition, there was an intracardiac echogenic mass 15 × 17 × 20 mm in diameter protruding from the left ventricular wall (Figure 1) near the apex. The vascular nature of the mass was demonstrable with color power angiography and the main feeding vessel was clearly visualized (Figure 2). Minimal ascites was observed. Other structures were normal. Cardiac hemangioma was prenatally diagnosed. On the follow-up scans at 33, 35 and 37 weeks’ gestation the cardiac size, pericardial effusion and ascites had not worsened but remained the same. Induction of labor was initiated at 37 weeks’ gestation and a healthy male fetus weighing 2770 g was delivered vaginally. Postnatal echocardiography demonstrated the tumor mass in the left ventricle arising from the pericardium with typical internal blood flow signals on color flow mapping. The main feeding vessels were clearly demonstrated. The heart was slightly enlarged. Magnetic resonance imaging (MRI) revealed the typical characteristics of a hemangioma. Ascites and pericardial effusion disappeared shortly after birth. The mass was scheduled to be removed later. However, at the age of 3 months the baby was still healthy without any signs of cardiac decompensation and the mass was smaller when compared with the cardiac size. On follow-up serial echocardiograms the tumor gradually regressed and completely disappeared at about 6 months of age. Cardiac tumors are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017% to 0.28%1. Rhabdomyoma is the most common benign fetal cardiac neoplasm, whereas hemangioma is extremely rare, occurring at a frequency of only 1 in 19 cardiac tumors1. Fetal cardiac hemangioma usually arises from the atrial wall or pericardium. Although several case reports of cardiac tumors have been published, very few cases of cardiac hemangioma have been diagnosed prenatally. Though benign in nature, cardiac hemangioma can obstruct inflow or outflow from the heart, leading to cardiac arrhythmia, cardiac decompensation or even hydrops fetalis. A tumor may interfere with blood flow through the heart by extrinsic compression or intracavitary obstruction and can be associated Figure 1 Fetal echocardiographic four-chamber view reveals an intracardiac mass in the left ventricle. IVS, interventricular septum; PE, pericardial effusion; Sp, spine.

Screening for hemoglobin E trait in pregnant women

a-Thalassemia yHbE disease is one of the most common severe genetic diseases in Thailand w1,2x, and screening is necessary for prenatal control. To identify HbE gene carriers, however, effective screening methods must be developed. The dichlorophenol indophenol precipitation test is widely usedw2x, but its efficacy is limited because of its high rate of false-positive results. We developed an HbE screening test for possible HbE gene carriersw1,3x. The objective of this study was to determine accuracy of the HbE screen test among pregnant Thai women. Pregnant women attending our antenatal care clinic between April 2001 and July 2002 were recruited at their first visit. Exclusion criteria were multiple pregnancies and a pregnancy complicated by anemia. To establish the carrier status a blood sample of 1 ml was taken for the HbE screening test and another for an HbA test as a gold 2 standard. The HbE screen test was performed as follows w3x:

Intrauterine intravenous transfusion therapy for hydrops fetalis due to anemia of uncertain causes

The treatment and prognosis of hydrops fetalis depend on the etiology or underlying fetal conditions. Intrauterine transfusions for fetal anemia can be effective in the selected cases [1,2]. Theoretically, anemia of unknown cause, after excluding common lethal problems such as Hb Bart’s disease, is probably justified for intrauterine transfusion. The purpose of the study was to demonstrate the possibility to reverse hydrops fetalis due to fetal anemia of unknown causes with intrauterine intravascular transfusion.