Supatra Sirichotiyakul

Single transvaginal sonographic measurement of cervical length early in the third trimester as a predictor of preterm delivery

Objective To evaluate the accuracy of a single sonographic measurement of cervical length early in the third trimester as a predictor of preterm delivery. Methods A total of 771 women attending the antenatal clinic at the Maharaj Nakorn Chiang Mai Hospital between January 1, 1990, and November 30, 1993, with singleton gestations, cervical competence, accurate dates of last menstrual period, and gestational ages between 28–30 weeks, were recruited into the study. Forty-one were excluded, ten because of induced preterm delivery, 24 because of measurement problems, and seven because they were lost to follow-up. We analyzed the remaining 730 women. Results Ninety-one (12.5%) women ended with preterm births and the remaining 639 (87.5%) delivered at term. The mean (± standard deviation) cervical lengths of the term and preterm groups were statistically significantly different at 37 ± 5 and 34 ± 6 mm, respectively (P < .001). The likelihood ratio of cervical length at various cutoff points was calculated. The appropriate cutoff point based on the receiver operating characteristic curve (35 mm) was associated with a significantly increased likelihood of preterm delivery (20 versus 7%) and was detected in two-thirds of preterm births. This cutoff point gave a sensitivity and specificity of 65.9 ± 5.1% (95% confidence interval [CI]) and 62.4 ± 5.2% (95% CI), respectively. Conclusion A single transvaginal sonographic measurement of cervical length at 28–30 gestational weeks can be used to predict the risk of preterm delivery, using a cutoff point of 35 mm, but its cost-effectiveness should be assessed further.

Sonographic Markers of Hemoglobin Bart Disease at Midpregnancy

Objective. To evaluate the efficacy of various sonographic markers at midpregnancy in predicting fetal hemoglobin Bart disease. Methods. Four hundred eighty‐eight pregnancies at risk of having fetuses with hemoglobin Bart disease were recruited for prenatal diagnosis with cordocentesis at 18 to 21 gestational weeks. Before cordocentesis, the sonographic markers, including cardiothoracic ratio, placental thickness, pericardial effusion, pleural effusion, ascites, subcutaneous edema, cord edema, dilated umbilical vein, and amniotic fluid index, were assessed and recorded. The definite fetal diagnosis was based on blood analysis. The efficacy of each sonographic marker in predicting hemoglobin Bart disease was evaluated by sensitivity and specificity. Results. Among 488 pregnancies undergoing prenatal diagnosis, 100 fetuses were proved to be affected by hemoglobin Bart disease. The cardiothoracic ratio gave the highest sensitivity, 95.0%, with specificity of 96.1%, followed by placental thickness. Signs of hydrops fetalis were observed in 33.0% of cases; they did not increase the sensitivity of the cardiothoracic ratio but strongly reinforced the diagnosis when they appeared. Conclusions. At midpregnancy, sonographic markers can effectively differentiate normal pregnancies from those with fetal hemoglobin Bart disease. Among couples at risk with no sonographic markers, the risk of having an affected child is nearly eliminated. The most sensitive marker was the cardiothoracic ratio, followed by placental thickness.

Alcoholization: The choice of intrauterine treatment for chorioangioma

Chorioangioma is a vascular tumor of the placenta. Most are small and asymptomatic, whereas the large tumors are clinically significant and often associated with polyhydramnios and fetal heart failure. To prevent fetal loss from these complications, many interventions have been proposed, including intrauterine transfusion in anemic cases and fetoscopic surgery to ablate the feeding vessels. The case presented herein had large chorioangiomas, 8 and 4 cm in diameter, associated with polyhydramnios and early signs of hydrops fetalis, diagnosed at 27 weeks gestation. After extensive counseling, we performed alcohol ablation of the feeding vessel of the larger tumor. Signs of fetal heart failure and hydrops fetalis disappeared dramatically. The pregnancy was extended for 2 weeks, followed by premature rupture of the membranes and spontaneous labor at 32 weeks gestation and a surviving female baby, weighing 1360 g, was delivered uneventfully. This preliminary experience suggests that alcoholization may be one of the best choices for this condition due to its high efficacy, simplicity, safety and very low cost. To our knowledge, this is the first report using alcoholization for the treatment of hydrops fetalis secondary to chorioangioma.

Antenatal sonographic features of 100 alpha-thalassemia hydrops fetalis fetuses.

To characterize the sonographic findings of α‐thalassemia hydrops fetalis.

Sonographic features of trisomy 18 at midpregnancy

Objective:  To evaluate the sonographic characteristics of the fetuses with trisomy 18 at 16–22 weeks of gestation.

Placental thickness at mid‐pregnancy as a predictor of Hb Bart's disease

The measurement of placental thickness can effectively differentiate normal pregnancies from affected pregnancies requiring invasive work‐up.

PRENATAL DIAGNOSIS OF β-THALASSEMIA MAJOR BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY ANALYSIS OF HEMOGLOBINS IN FETAL BLOOD SAMPLES

In Thailand and adjacent countries, most of the β-thalassemia genes are β0-thalassemia mutations that prevent the production of Hb A. We propose the quantitation of the Hb A fraction in fetal blood in the mid-trimester of pregnancy by automated high performance liquid chromatography as a reasonable prenatal diagnostic method to be applied in areas with limited laboratory facilities. Forty pregnant women at risk of delivering a child with β-thalassemia major were identified using an erythrocyte osmotic fragility test and quantitation of Hb A2. Cordocentesis was performed at the gestational age of 18–22 weeks and fetal blood was analyzed for hemoglobin fractions by automated high performance liquid chromatography. The β-globin gene mutations were characterized by β-globin gene sequencing. The 4 bp deletion at codons 41/42 (−TTCT) was the most frequent of the 40 β-thalassemia mutations observed (20/40 = 50%), followed by the splice site mutation IVS-I-1 (G → T) (7/40 = 17.5%), the nonsense mutation at codon 17 (A → T) (7/40 = 17.5%), the nonsense mutation at codon 35 (C → A) (3/40 = 7.5%), and the β+ -thalassemia promoter mutation at −28 (A → G) (3/40 = 7.5%). High performance liquid chromatography revealed nine fetuses which had only Hb F and no Hb A. All were homozygotes or compound heterozygotes for β0-thalassemia mutations. In the remaining 31 fetuses, a Hb A peak was present in the chromatograms. One fetus with 0.5% Hb A was a compound heterozygote for the −28 (A → G) and codons 41/42 (−TTCT) mutations. In the remaining 30 fetuses, the Hb A values ranged between 0.8 and 7.4%. Twenty of these, with a Hb A concentration of 1.82 ± 0.49% (range 0.8–2.8%), were β-thalassemia heterozygotes. The remaining 10 fetuses had Hb A values of 4.89 ± 1.47% (range 2.9–7.4%) and normal β-globin genes. The absence of Hb A in homozygotes or compound heterozygotes for β0-thalassemia mutations and the presence of measurable amounts of Hb A in heterozygotes and normal homozygotes, permits the diagnosis of fetuses expected to develop postnatal β-thalassemia major.

Sensitivity and specificity of mean corpuscular volume testing for screening for α‐thalassemia‐1 and β‐thalassemia traits

Aim: To evaluate the sensitivity, specificity, positive predictive value and negative predictive value of mean corpuscular volume (MCV) testing for screening for both α‐thalassemia‐1 and β‐thalassemia traits.

Intrauterine treatment for an acardiac twin with alcohol injection into the umbilical artery

An acardiac twin is a unique complication of monochorionic twinning, in which a normal pump twin perfuses the acardiac twin. The mortality rate of the pump twin is greater than 50%. Herein we present the successful treatment of an acardiac twin with alcoholization as follows. An acardiac twin was diagnosed at 24 weeks gestation. Circulation interruption of the acardiac twin was successfully achieved by injection of absolute alcohol (5 mL) into the intra‐abdominal umbilical artery. Serial ultrasound after the procedure revealed normal growth of the pump twin, whereas the acardiac twin was shrinking. Spontaneous premature delivery at 34 weeks gestation resulted in a normal surviving female baby weighing 2410 g and an acardiac female fetus weighing 300 g. This experience suggests that this simple technique may be an alternative treatment for an acardiac twin.

Middle cerebral artery peak systolic velocity of healthy fetuses in the first half of pregnancy

The purpose of this study was to establish normative data of middle cerebral artery (MCA) peak systolic velocity (PSV) in the first half of normal pregnancies (11–22 weeks).