Influence of alpha-thalassemia trait on the prevalence and severity of anemia in pregnancy among women in Kuwait.

Alpha-thalassemia is very common in the Kuwaiti population, but its influence on anemia of pregnancy has not been previously investigated. We have screened a group of 59 anemic (Hb < 11 g/dl) pregnant women for the alpha-thal-2 (-alpha-3.7 kb) deletion which is the commonest alpha-thal allele in this community, using a polymerase chain reaction method. A control group of 35 nonanemic (Hb > or = 11 g/dl) pregnant women was studied for comparison. All the women were in the second or third trimester of pregnancy. Among the 94 women in both groups, 69 (73.4%) had a normal complement of alpha-globin genes (alphaalpha/alphaalpha), 18 (19.1%) were heterozygotes (-alpha/alphaalpha) and 7 (7.4%) were homozygotes (-alpha/-alpha) giving an allele frequency of 17.0%. Among the anemic group, there were 44 (74.6%) individuals with a normal genotype, 9 (15.3%) heterozygotes and 6 (10.2%) homozygotes. In the nonanemic group, the corresponding prevalence figures were 25 (71.4%), 9 (25.7%) and 1 (2.9%), respectively. The difference between these distributions was statistically significant (chi2 = 37.5, p < 0.0001). However, the mean Hb values were similar in heterozygotes, homozygotes and normal individuals. We, therefore, conclude that while the alpha-thal trait affects the prevalence of anemia among pregnant Kuwaiti women, it does not affect its severity.