Fetal structural anomaly screening at 11-14 weeks of gestation at Maharaj Nakorn Chiang Mai Hospital.

OBJECTIVE: To determine the detection rate by ultrasound scanning of fetal anomaly by first trimester (11-14 weeks of gestation). MATERIAL AND METHOD: A prospective descriptive study of 597 pregnant women undergoing Nuchal Translucency (NT) measurement at 11-14 weeks of gestation at Maharaj Nakorn Chiang Mai Hospital. The sonographic examinations focused on NT thickness and fetal structural survey. The final diagnoses were based on neonatal outcomes assessed by the pediatricians and abortuses evaluated by the pathologists. The main outcome measure was the detection rate of fetal anomaly using ultrasonographic examination. RESULTS: Of 597 pregnant women recruited into the present study, the mean age was 29.41 +/- 5.8 years, the incidence of fetal anomaly was about 4% (24 from 597 cases). The detection rate by first ultrasound scans was 58% (14 from 24 cases) and the most common detected structural anomaly was cystic hygroma and exencephaly. The rate of undetected fetal anomalies was 42% (10 from 24 cases). Abnormal NT was found in 16 from a total of 597 cases (2.7%), most of them, however, had normal karyotype and no gross anomaly at birth. CONCLUSION: First trimester (11-14 weeks) ultrasound scan is probably a useful method for detection of fetal structural anomalies with a relatively high detection rate, and may be a good adjunct to the conventional examination.

Prenatal diagnosis of hemoglobin Bart's hydrops fetalis by HPLC analysis of hemoglobin in fetal blood samples.

Since HbF and HbA are not found in fetuses with Hb Bart's hydrops fetalis the feasibility of prenatal diagnosis of homozygous alpha-thalassemia 1 by fetal hemoglobin typing was examined. Blood samples were obtained from fetuses at 18 to 22 weeks of gestation by cordocentesis in 32 pregnant women at risk of having a child with homozygous alpha-thalassemia 1 (alpha-thal-1). The samples were analyzed by a PCR-based method for the diagnosis of alpha-thal-1 (SEA type) and the proportion of hemoglobin fractions were determined by automated HPLC. DNA analysis showed that 8 of the 32 fetuses were homozygotes for alpha-thal-1, 17 were heterozygous for alpha-thal-1 (alpha-thal-1 trait), and a normal complement of four a-globin genes was found in 7 cases. The Hb typing in fetuses with homozygous alpha-thal-1 showed a peak of unbound Hb (Hb Bart's and Hb Portland) and no HbF, HbA and HbA The alpha-thal-1 trait chromatograms showed unbound Hb, pre HbF, HbF and HbA peaks. The chromatogram of normal fetuses showed HbF and HbA peaks without HbA2. In these cases the HbA proportion is between 3% and 10% with no apparent differences between the 18h and 22nd week of gestation. As the analysis of fetal Hb types by HPLC is facile and speedy and the results correspond with those obtained by DNA analysis, fetal Hb typing by automated HPLC is a convenient prenatal diagnostic method for homozygous alpha-thal-1. The method is recommended for prenatal diagnosis in populations with a high frequency of alpha-thal-1.

Prenatal sonographic markers of trisomy 21.

OBJECTIVE: To describe the sonographic characteristics of fetuses with trisomy 21. DESIGN: A prospective descriptive analysis. SETTING: Department of Obstetrics and Gynecology, Faculty of Medicine, Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University. SUBJECTS: Pregnancies at risk of trisomy 21 between 14-27 weeks' gestation. RESULTS: Thirty-six fetuses with subsequently proven trisomy 21 were prenatally evaluated by ultrasound in the second trimester. The main indications for detailed ultrasound examinations were advanced maternal age and abnormal findings on routine ultrasound. All of them had chromosome analysis by amniocentesis or cordocentesis. Nineteen (52.78%) had one or more abnormal findings. The common sonographic findings included thickened nuchal fold (33.33%), short femur (19.44%), and mild pyelectasis (22.22%). The other uncommon abnormalities included major anomalies (cardiac malformations, ventriculomegaly, duodenal atresia, esophageal atresia), hyperechoic bowel, echogenic intracardiac foci, abnormalities of extremities. In this study, rare minor markers but more specific markers including sandal gap, clinodactyly and mid-phalanx hypoplasia of the fifth finger were demonstrated. CONCLUSION: About half of the fetuses with trisomy 21 had abnormal sonographic findings in the second trimester. The most common marker was thickened nuchal fold. Although prenatal ultrasound can not permit a definite diagnosis of trisomy 21, about half of them have sonographic markers, warranting cytogenetic testing.

Prenatal diagnosis: 10-year experience.

To evaluate the indications and results of prenatal diagnosis of the high risk pregnant women attending the antenatal care clinic at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University during 1988-1998, we analysed 2,315 amniocenteses, 1,000 cordocenteses, and 11,895 obstetric ultrasound examinations. Among the amniocentesis group, 2,017 cases (87%) were done with the indication of advanced maternal age. The prevalence of major abnormal fetal chromosomes among high risk pregnancies was 1:58. Of 1,000 cases with cordocentesis, the most common indication was fetal risk of severe thalassemia (658 cases; 65.8%) and followed by fetal risk of chromosome abnormalities (272 cases; 27.2%). In the group of cordocentesis for diagnosis of thalassemia, 99 and 49 pregnancies were affected with Hb Bart's disease and homozygous beta-thalassemia, respectively. Thirty three cases with indication of chromosome analysis had fetuses with abnormal chromosomes. The major indications of ultrasonography included suspicion of intrauterine growth restriction (IUGR), determination of gestational age and screening anomalies, respectively. In conclusion, our extensive experience has enabled us to prenatally detect most fetuses with severe thalassemia, and fetuses with abnormal chromosomes as well as anomalies in a significant number, contributing a great deal to our population. Therefore, we recommend that systematic prenatal diagnosis, either amniocentesis, cordocentesis or ultrasound should be provided to every high risk pregnant woman for a healthy newborn.

Prenatal sonographic diagnosis of holoprosencephaly.

The purpose of this series was to describe the sonographic features of fetal holoprosencephaly prenatally. The study was undertaken at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University. A total of 12 fetuses with prenatal diagnosis of holoprosencephaly were sonographically evaluated and followed-up. The study revealed that all showed monoventricular cavity, fused thalami, no falx and cavum septum pellucidum. Eight of them were correctly diagnosed sonographically in the first two trimesters. Extrafacial anomalies were also identified in half of the fetuses and all of them had facial abnormalities. Twenty-five per cent (3 cases) had polyhydramnios and only one case had oligohydramnios. Chromosome study revealed that 70 per cent had normal chromosomes, 30 per cent were aneuploidy, trisomy 13; 2 cases and trisomy 18; 1 case. In conclusion, this series indicates that ultrasound has a high predictive value in the diagnosis of holoprosencephaly. The most valuable clue to the diagnosis is the demonstration of the single ventricle. Additionally, demonstration of facial abnormalities may add confidence to the diagnosis. Conversely, should any of these facial features be serendipitously encountered, a careful examination of the intracranial contents is recommended.

Sexually transmitted disease prevalence in brothel-based commercial sex workers in Chiang Mai, Thailand: impact of the condom use campaign.

One hundred and ninety five (195) brothel-based commercial sex workers (CSW) in Chiang Mai, Thailand, were screened for sexually transmitted disease (STD) between October 1994 and April 1995, prior to their enrollment in a multi-center comparative trial of the effectiveness of two strategies using male and female condoms. These CSW had a mean age of 22.2 (SD 4.3) years. Forty-seven per cent were Thai and 57.4 per cent had no formal education. Median duration of prostitution was 16 months and median cost for sexual service was 50 baht (US$ 2) per client. Ninety-four per cent of CSW reported always using condoms with clients. There were 63 (32.3%) CSW infected with at least one type of the STD screened. The prevalence of STD included chlamydial infection (16.9%), gonococcal infection (14.4%), condyloma accuminata (4.6%), moluscum contagiosum (2.6%) and trichomoniasis (1.0%). There was no statistically significant risk factor for STD found in this study. Despite an active programme for prevention of STD in CSW and the provision of free condoms, STD were diagnosed in one-third of the screened CSW in Chiang Mai. The programme needs to be strengthened by more intensive education and practice in the correct and consistent use of condoms and integrated with other STD prevention programmes.