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 VACTERL association: a case report.

A prenatal diagnosis of VACTERL association, a combination of vertebral (V), anal (A), cardiac (C), tracheoesophageal (TE), renal (R) and limb (L) anomalies was made at 30 weeks of gestation, based on the sonographic demonstration of vertebral defects, bilateral renal agenesis, and left lower limb defects. Additionally, severe oligohydramnios and fetal growth restriction were also documented. After proper counseling, elective termination of pregnancy was done, resulting in a stillborn infant with multiple malformations compatible with the VACTERL association. The postnatal X-ray and autopsy revealed verterbral defects, anorectal atresia with undetermined sex, cardiac defect of ventricular septal defect, tracheal agenesis with distal atresia of esophagus, bilateral renal agenesis, and limbs defects. The chromosomal study revealed normal, 46,XY. This report emphasizes the important role of prenatal ultrasound in the diagnosis and management of this disorder.

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.