Proposed screening criteria for beta-thalassemia trait during early pregnancy in southern China.

This study was carried out to evaluate whether it is effective to use mean corpuscular volume (MCV) <80 fL as a screening test in the first step of screening for beta-thalassemia (beta-thal) trait in southern China. The data of hematological testing in the first or early second trimester of gestation of 449 pregnant women who underwent prenatal diagnosis for beta-thal were retrospectively reviewed. Of these, six (1.3%) had an MCV value >80 fL, ranging from 80.3 to 83.4 fL. This meant that six at-risk pregnancies would have been missed if only an MCV cut-off value of <80 fL had been used for screening. All subjects having a normal MCV value carried the same -28 (A>G) mutation, accounting for 9.8% (6/61) of the total number of mother with this mutation. If screening had been based on the mean corpuscular hemoglobin (MCH) <27 pg, all 449 pregnant women with beta-thal trait would have been detected. We suggest that all pregnant women presenting at an antenatal clinic with an MCH of <27 pg rather than an MCV of <80 fL should be investigated further to confirm or exclude a diagnosis of beta-thal trait in our region.

Hydrops fetalis caused by homozygous alpha-thalassemia and Kidd antigen alloimmunization in a Chinese woman.

We report a case with hydrops fetalis resulting from homozygous alpha-thalassemia and alloimmune hemolytic anemia due to anti-JK3. This is one of the few cases with immune- and nonimmune-induced hydrops fetalis.

[Follow-up of 3 605 cord blood donors after 6 months of cord blood donation in Guangzhou cord blood bank].

To study the program of evaluating mothers and infants after 6 months of cord blood donation, from June 1998 to February 2004, all mothers after 6 months of cord blood donation were followed-up by phone calls or letters to report on the health condition. The results showed that when 3 195 mothers were visited by phone calls, 18 mothers declined to answer. 392 letter were send to those who could not be found by phone, 15 of whom wrote back. The average time to talk with each mother was approximately 12 minutes. Follow-up on the baby donors showed two cases with chromosome abnormality, one with hypothyroidism, one with neutropenia, one with albinism and 5 dead with unclear reasons. The cord blood components from all these abnormal donors found were discarded. In conclusion, the programs to evaluate mother and baby after 6 months of cord blood donation seems important in quality control of the components stored in cord blood bank.

Carrier screening for alpha- and beta-thalassemia in pregnancy: the results of an 11-year prospective program in Guangzhou Maternal and Neonatal hospital.

OBJECTIVES: To evaluate the first prospective screening program in China for control of alpha and beta-thalassemia in the population of pregnant couples. METHODS: During the period between January 1993 and December 2003, a hospital-based preventive program was conducted at the biggest birth center in Guangzhou, with 1/17 of all deliveries in this city referred annually by use of conventional heterozygote screening strategy in combination with the system of regular healthcare examination in pregnancy. RESULTS: The screened records included 49 221 pregnant women, and 4503 husbands of the pregnant women showed positive on the screening test. Of the at-risk couples, there were 198 for alpha-thal (4.4%) and 83 for beta-thal (1.8%), respectively. Genetic counseling was offered to all at-risk couples and a successful prenatal diagnosis was performed for 269 out of 281 (95.7%) for alpha- or beta-thal major, with the remaining 12 couples refusing to accept prenatal diagnosis. Out of 187 pregnancies at risk for homozygous alpha0-thal and 82 at risk for beta-thal major, 51 hydrops fetalis with Hb Bart's and 18 beta-thal major were identified. All pregnancies with affected fetuses were voluntarily terminated, leading to a marked reduction of severe alpha- and beta-thal births at this hospital since the program has been launched. CONCLUSIONS: Our hospital-based program proved to be highly effective in reducing severe thals in pregnant populations.

[Studies on safety of cordocentesis guided by transabdominal ultrasound for prenatal diagnosis].

OBJECTIVE: To assess the safety and efficacy of diagnostic cordocentesis during pregnancy. METHODS: During March 1990 to June 2003, 2403 consecutive cordocenteses were performed under transabdominal ultrasound guidance at Guangzhou Women and Children's Hospital. The results of each procedure was prospectively collected and subsequently analysed in terms of operational complications and pregnancy outcomes. RESULTS: Success rate of cordocentesis: totally 2368 procedures (98.5%) were done successfully at the first attempt, and 35(1.5%) required repeated cordocentesis, 16 of which were performed successfully at second attempt. Duration of cordocentesis: In 75.5% cases, the procedure was completed in less than 5 min, and in 93.0% cases in less than 10 min. COMPLICATIONS: Transient bleeding at puncture site was observed in 315 cases (13.1%), transient fetal bradycardia in 125 cases (5.2%), and chorioamnionitis in 2 cases (0.1%). Pregnancy outcomes: The total fetal loss rate was 0.8% (18 cases of abortions). The rate of premature birth after cordocentesis was 0.2% (4 cases). CONCLUSION: Cordocentesis during pregnancy is a useful, relatively safe, and effective procedure for prenatal diagnosis.

[Use of capillary electrophoresis to determine hemoglobin A2 in healthy adults and alpha- and beta-thalassemia carriers].

OBJECTIVE: To evaluate the capillary isoelectric focusing (CIEF) method for the estimation of blood hemoglobin A2 (Hb A2) concentrations in routine thalassemia screening. METHODS: A total of 105 samples from healthy adults and 93 samples with positive phenotypes were collected by routine thalassemia screening. CIEF was compared with Helena spife combo electrophoresis system for Hb A2 measurement and its precision and reproducibility were tested by analyzing intra-assay or inter-assay coefficient of variations(CVs). The reliability and veracity of Hb A2 measurement by CIEF for the detection of alpha- and beta- thalassemia including Hb E were evaluated by genotyping of 93 consecutive samples for routine thalassemia screening. RESULTS: By us e of CIEF for measurement of Hb A2 in a local healthy adult population, the range of reference value(3.59%-5.23%) was obtained. The results of CIEF showed good linearity relation to that of conventional Hb electrophoresis assay. All thalassemia carriers (43 cases of alpha-thals and 44 of beta-thals) or Hb E carriers (6 cases) presumptively identified by the present CIEF for the quantification of Hb A2, combined with routine RBC parameters for indicating microcytosis and hypochromia were confirmed to be the heterozygous or compound heterozygous defects of alpha- or beta- globin gene by molecular diagnosis, without any false positive or false negative results. CONCLUSION: The measurement of Hb A2 by CIEF method is rapid, precise and reproducible; it could be used in routine screening for alpha- or beta- thalassemia.