antihistamines before or during pregnancy and risk of early-onset pre-eclampsia in allergic women

Last edited 10/2022 and last reviewed 10/2022

Antihistamines before or during pregnancy and risk of early-onset pre-eclampsia in allergic women

Pregestational maternal allergy is associated with early-onset pre-eclampsia (1)

• study to assess the correlation between maternal pre-gestational allergy, and early-onset and late-onset preeclampsia, respectively
• was a retrospective cohort study including all women giving birth in the Norwegian cities of Stavanger (1996-2014) and Bergen (2009-2014)
  • pre-gestational asthma, allergy, other known risk factors for preeclampsia, maternal age and parity were obtained from the electronic medical record system
  • main outcome variables were early-onset and late-onset preeclampsia (before and after 34 completed weeks of gestation, respectively). We used multinomial logistic regression to estimate odds ratios (OR) with 95% confidence intervals (95% CI) for early and late-onset preeclampsia in women with pre-gestational allergy when compared to women without allergy, adjusting for covariates. Predicted probabilities for the outcomes were also calculated.
  • of the 110064 included pregnancies, 2 799 developed late-onset preeclampsia (2.5%) and 348 developed early-onset preeclampsia (0.3%)
  • pre-gestational allergy increased the risk of early-onset preeclampsia (OR 1.7, 95% CI 1.3-2.4), and reduced the risk of late-onset preeclampsia (OR 0.8, 95% CI 0.7-0.9)
• findings add valuable information on preeclampsia as an immunological complication of pregnancy and corroborate the understanding of early- and late-onset preeclampsia as two different entities
• supports the hypothesis of pre-eclampsia as a disorder of immune regulation, and prompts the question if antihistamines, used to treat allergy, affect the risk of developing pre-eclampsia in allergic women

Levels of histamine in blood are altered in pregnancy, indicating its biological importance for a successful pregnancy

A population-based cohort study showed that antihistamine use before or during placentation was associated with reduced risk of developing early-onset pre-eclampsia in allergic women compared with women using antihistamines after placentation (2)

Reference:

• Sande AK et al. Maternal allergy as an isolated risk factor for early-onset preeclampsia: an epidemiological study. J Reprod Immunol 2018;127:43-7.doi:10.1016/j.jri.2018.04.004
• Sande AK et al. Use of antihistamines before or during pregnancy and risk of early-onset pre-eclampsia in allergic women: a population-based cohort study.BMJ Open 2022;12:e061837