Association between hypertensive disorders of pregnancy and the risk of asthma, eczema and allergies in offspring: A systematic review and meta‐analysis
Authors: Conlan Nicola , Maher Gillian M. , Al Khalaf Sukainah Y. , McCarthy Fergus P. , Khashan Ali S. 
Published: October 2020

Objective

Conduct a systematic review and meta‐analysis examining the association between hypertensive disorders of pregnancy (HDP) and risk of asthma, eczema, food allergies and allergic rhinitis in the offspring.

Design

A systematic review and random‐effects meta‐analyses were used to synthesize the published literature. PRISMA guidelines were followed throughout. Two independent reviewers carried out data extraction and quality assessment of included studies. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess certainty of findings.

Data Sources

A systematic search of PubMed, Embase, Web of Science and CINAHL was performed from inception of databases‐21 April 2020, supplemented by hand‐searching reference lists of included articles.

Eligibility Criteria

Two reviewers independently reviewed titles, abstracts and full‐text articles. English language, cohort, case‐control and cross‐sectional published studies examining the association between HDP (primary exposure: pre‐eclampsia; secondary exposures: all other HDP) and asthma, eczema, food allergies and allergic rhinitis were included.

Results

Of the 2833 studies retrieved, 14 studies met inclusion criteria. Of these, 11 studies reported evidence of association between HDP and atopic disorders. Thirteen studies reported estimates for asthma. Seven of these included adjusted estimates (including 3 645 773 participants) for a pre‐eclampsia‐asthma relationship resulting in a pooled odds ratio (OR) of 1.14 (95% CI: 1.04, 1.26) (I2 = 62%). However, this OR was reduced to 1.08 (95% CI: (0.78, 1.48) when the large registry‐based cohort studies were excluded, and only studies using parent‐reported measures to determine a diagnosis of asthma were included. Four studies included adjusted estimates (including 254 998 participants) for other HDP and asthma (pooled OR: 1.02, 95% CI: 0.96, 1.09) (I2 = 0%). Two studies provided adjusted estimates (including 1 699 663 participants) for a pre‐eclampsia‐eczema relationship (pooled OR: 1.06, 95% CI: 0.98, 1.14) (I2 = 0%). One study including pre‐eclampsia‐food allergies was identified (OR: 1.28, 95% CI: 1.11, 1.46). Three studies examined a HDP (including pre‐eclampsia) and allergic rhinitis relationship, with effect estimates ranging from 1.14 to 2.10. Studies were classified as low or low‐moderate risk of bias, while GRADE certainty of findings were low to very low.

Conclusions

While pre‐eclampsia was associated with a possible increased risk of asthma in offspring, there was no evidence for a relationship between other HDP and asthma. There is a lack of published literature examining the association between HDP and eczema, food allergy and allergic rhinitis. Further primary research is warranted to gain a better understanding of the association between HDP and the risk of childhood atopic disease.

Systematic review registration

Review protocol in appendix.