A retrospective comparison of pregnancy outcomes between women with alpha-thalassaemia 1 trait and normal controls

Abstract

The objective of this retrospective cohort study was to compare pregnancy outcomes between low-risk pregnant women with alpha-thalassaemia-1 trait and normal controls. The database of the Maternal–Foetal Medicine unit was used to identify low-risk singleton pregnant women complicated by alpha-thalassaemia-1 trait who gave birth between January 2002 and October 2014. The low-risk pregnancies with non-carrier status for thalassaemia were assigned into the control group, with a control-to-case ratio of 10:1. During the study period, 595 women with alpha-thalassaemia-1 trait and 5950 normal controls were identified. There was no significant difference in the incidence of preterm birth and most obstetric outcomes between the two groups. However, a statistically significant difference was detected between them in terms of gestational age at delivery, 37.76 ± 2.81 vs. 38.11 ± 2.50 weeks (p = .001), birth weight, 2876 ± 581 vs. 2948 ± 527 g (p = .002) as well as the rate of low-birth weight, 17.1 vs. 12.8% (p = .002). In conclusion, this study provides new insights that alpha-thalassaemia-1 trait has minimal effect on gestational age at delivery and low-birth weight whereas other common adverse pregnancy outcomes are not increased.

Impact statement

• What is already known on this subject: Thalassaemia trait is associated with some degree of anaemia.

• What the results of this study add: The prevalence of common adverse outcomes such as preterm birth, stillbirth, low Apgar scores and pregnancy-induced hypertension were not significantly different between both the groups, possibly caused by too small sample size to gain enough power. However, the rate of low-birth weight was significantly increased among pregnancy with alpha-thalassaemia-1 trait.

• What the implications are of these findings for clinical practice and/or further research: The information may be provided for alpha thalassaemia-1 trait mothers and their families. Physicians should guard against the occurrence of adverse pregnancy in these mothers. Prospective control study should be conducted to overcome the limitation of retrospective nature.

Keywords:

• Alpha-thalassaemia-1
• haemoglobin
• outcomes
• pregnancy
• trait

Acknowledgements

The authors wish to thank the National Research University Project under Thailand's Office of the Higher Education Commission and Diamond Research Grant of Faculty of Medicine, Chiang Mai University for financial support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Diamond Research Grant of Faculty of Medicine, Chiang Mai University.