Pregnancy outcomes in women affected by fetal alpha-thalassemia: a case control study.

To evaluate the possible associations between fetal α-thalassemia and risk of adverse pregnancy outcomes using a provincial woman-child health service information database in China. This was a case control study (N = 438,747) in which we compared all singleton pregnancies of women with or without the α-thalassemia trait from May 2016 to May 2020, and where women with the trait were further allocated to a normal fetal group, a group of fetuses with the α-thalassemia trait, and a fetal group with hemoglobin H (HbH) disease according to the results of fetal DNA analysis. With thalassemic women whose fetuses were normal as the reference, fetuses in the HbH disease group showed a higher increase in the odds of Apgar scores being < 7 at 1 min (adjusted odds ratio [aOR], 2.79; 1.03-7.59) and 5 min (aOR, 4.56; 1.07-19.40). With non-thalassemic women as the reference, these trends were more obvious (aOR, 4.83; 2.55-9.16; aOR, 6.24; 2.75-14.18, respectively); whereas the normal fetal group was more likely to be diagnosed with postpartum hemorrhage (aOR, 1.66; 1.10-2.50). In addition, fetal HbH disease and gestational age were two independent factors influencing low Apgar scores, and their combination reflected medium accuracy in Apgar predictions.