The disease course of hereditary angioedema (HAE) may be worsened during pregnancy and breastfeeding, whereas normal vaginal delivery without anesthesia is associated with fewer HAE attacks, according to a study published in Immunology and Allergy. 

Various factors can trigger HAE attacks. Because pregnancy and breastfeeding are periods during which significant hormonal alterations occur, there are concerns that HAE attacks may be heightened during this time. In addition, childbirth can be traumatic by nature. Researchers have sought to study the impact of pregnancy and childbirth on HAE attack rates, if any. 

The authors of the study assessed the nature and frequency of HAE attacks during pregnancy and breastfeeding, as well as whether childbirth is a risk factor in the precipitation of attacks. The research team chose 48 patients with HAE who had 88 full-term pregnancies between them. They then followed up on these cases between 1999 and 2021. 

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Patients were separated into 2 groups—the first had a diagnosis of HAE prior to pregnancy and the second had one after. Among the 88 full-term pregnancies were 21 miscarriages (none of which were associated with an HAE attack), 6 induced abortions, and 3 fetal deaths. Eighty-three patients breastfed their child. 

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For patients in group 1 (n=34), the number of HAE attacks was higher during pregnancy, breastfeeding, and the period following breastfeeding. In addition, the severity of HAE attacks was higher during pregnancy compared with the prepregnancy, breastfeeding, and postbreastfeeding periods. 

In group 2 (n=54), the picture was more mixed. A total of 59.3% of pregnancies had an increased number of HAE attacks, whereas 24.1% experienced fewer attacks. Fifty-four individuals reported that the severity of these attacks were higher during pregnancy, 9 reported a lower severity, and 6 experienced no changes. 

The research team also reported that patients who had a normal vaginal delivery (n=47) without anesthesia (5/47) had the lowest number of attacks compared with those who delivered via cesarean section (n=41). 

“Our study showed that both the number and the severity of HAE attacks increased during pregnancy and breastfeeding periods,” the authors concluded. “Furthermore, vaginal delivery without anesthesia seems to be safe; therefore, if there are no special indications for cesarean section, clinicians should recommend vaginal delivery.” 


Eyice Karabacak D, Can A, Demir S, et al. How does pregnancy and type of delivery affect the clinical course of hereditary angioedemaInt Arch Allergy Immunol. Published online September 6, 2023. doi:10.1159/000531074