Contaxt: Every year in India 6000 to 8000 children are born with thalassaemia major. The birth of such a child produces considerable physical and economic strain on the affected child, its family and the community at large. Thus, the emphasis must shift from the treatment to the prevention of such births in the future.
OBJECTIVE: To find out the prevalence of the Beta Thalassaemia trait among the pregnant women who attended the antenatal clinics in a Primary Health Centre, by using the NESTROF test; to describe the socio-demographic characteristics of the study subjects, to find out the pregnancies which were \'at risk\' of delivering babies with Thalassaemia major and to find out the \'awareness\' of the pregnant women regarding Thalassaemia.
METHODS: This exploratory study was conducted in a PHC which was attached to the Department of Community Medicine of a medical college which was situated in Bangalore, India, for a period of 3 months. All the pregnant women who attended the antenatal clinic and the husbands of the NESTROF positive women were included in the study. The details regarding the sociodemographic characteristics of the women were collected on a structured proforma and the NESTROF test was performed.
RESULTS: Out of the 210 pregnant women who were tested, 18 (8.5%) were thalassaemia carriers. 12 (66.6%) of them were between 20 - 25 years of age. 5 (27.7%) were born out of 2(nd) degree consanguineous marriages. 7 (38.8%) had a history of abortions, among which 6 (33.3%) were in the 1(st) trimesters of their pregnancies. Out of the 18 positive women, 9 (50%) had turned up with their husbands. All of the husbands were negative for the Thalassaemia carrier status. Thus, there was no pregnancy which was at a risk of delivering babies with thalassaemia major. None (100%) of the pregnant women were aware of the disease, thalassaemia.
CONCLUSIONS: The prevalence of the Beta Thalassaemia trait among the pregnant women was 8.5%.

BACKGROUND: Genes for thalassaemia, haemoglobin S, Glucose-6-phosphate dehydrogenase which confer resistance to malaria are found in high frequencies in Nigeria, 25% of the population being carriers of the sickle cell trait while another 25% are hemizygous for the G6PD gene. The frequency of alpha thalassaemia is equally high among Nigerians but there is little information on beta thalassaemia in this population. A recent study however suggest a high prevalence of beta thalassaemia in the same population, hence the need for this study.
METHODS: Haemoglobin A(2) and HbF were determined in healthy adults who have haemoglobin A genotype by elution after electrophoresis and alkaline denaturation methods respectively.
RESULTS: The mean HbA(2) among the subjects was 3.3% (range 2.0-5.6%) while the mean HbF was 2.6% (range 0.4-8.8%). Twenty-six percent of the subjects had HbA(2) values higher than 3.9% while 86% had HbF values greater than 1%, twenty-four percent had elevated HbA(2) and HbF. The mean HbA(2) value was 2.7% among those with HbF <1%, 3.6% among those with HbF 1-3% and 3.1% among those with HbF >3%.
CONCLUSIONS: These findings confirm that the frequency of beta thalassaemia in western Nigeria is higher than previously thought and that many of the individuals studied may be silent carriers of the beta thalassaemia trait. Its presence may also have been masked by the high prevalence of alpha thalassaemia in the same environment. It is therefore important to consider beta thalassaemia trait as a differential diagnosis in patients who present with haemolytic anaemia in this environment.