Results of Thalassemia Screening in Pregnant Women at Taksin Hospital

Abstract

Results of Thalassemia Screening in Pregnant Women at Taksin Hospital

Phiangjit Wiruchpongsanon MD.*

Pongsri Suaysom BNS**

* Department of Obstetrics and Gynecology, Taksin Hospital, Bangkok Metropolitan Administration (BMA)

** Nursing Department, Taksin Hospital, Bangkok Metropolitan Administration (BMA)

Objectives: To determine the rate of couples at risk of having a baby with severe thalassemia and the rate of fetuses affected with severe thalassemia in pregnant women who had thalassemia screening.

Method: This was a retrospective descriptive study. Data on blood tests for thalassemia screening of all consecutive pregnant women, and of their husbands, who initially attended the antenatal clinic at Taksin Hospital, BMA from October 1, 2007 to September 30, 2008 were collected. Blood tests included mean corpuscular volume (MCV), dichlorophenol indophenol (DCIP) and/or hemoglobin (Hb) typing. Prenatal diagnosis of the high risk couples were also recorded.

Results: During the study period, all 4,397 women who presented at the antenatal clinic for their first antenatal care underwent blood screening for thalassemia. Of these; 1,893 (43.1%) had positive screening. Among the screen positive women, 1,105 (58.4%) of their husbands had thalassemia screening and 649 (58.7% of the husbands who were screened) were screen positive. Out of the screen positive husbands, 501 (77.2%) had abnormal Hb typing. Considering 501 couples with abnormal Hb typing, there were 56 couples at risk of having a baby with severe thalassemia (11.2%) or 1.3% of all 4,397 women who had thalassemia screening. Among 56 couples at risk, 44 (78.6%) underwent DNA analysis for b or a globin gene and 18 were confirmed as couples at risk by this test. When combining these 18 couples with another 12 couples at risk of having a baby with severe thalassemia by Hb typing without DNA study, there were 30 couples who needed prenatal diagnosis. Of these, 17 (56.7%) actually had prenatal diagnosis which resulted in two cases of severe thalassemia (0.05% of pregnant women who had thalassemia screening).

Conclusion: In pregnant women who had thalassemia screening, the rate of couples at risk of having a baby with severe thalassemia was 1.3% while the rate of affected fetuses with severe thalassemia was 0.05%.

Keywords: thalassemia screening, pregnant women, couple at risk, severe thalassemia