Associations of childhood adiposity and changes in adiposity status from childhood to adulthood with pregnancy hypertension

Objective(s): To investigate the associations between adiposity in childhood, and adiposity change from childhood to adulthood, with pregnancy hypertension.

Study Design: The study followed-up 985 girls from the 1985 Australian Schools Health and Fitness Survey (aged 9-15 years) who were ever pregnant in 2004-2006 and/or 2009-2011. In childhood, overweight and obesity were defined by age-sex-specific international standard for body mass index (BMI) and in adulthood as BMI ≥ 25 kg/m². Childhood and adult abdominal obesity were defined as waist-to-height ratio (WHtR) ≥ 0.5. A subsample of adults had abdominal obesity measures (n = 549).

Main Outcome Measures: Pregnancy hypertension was self-reported as having had high blood pressure during or due to pregnancy.

Results: Childhood overweight/obesity (relative risk [RR] = 1.66, 95% confidence interval [CI]:1.07-2.52) and abdominal obesity (RR = 2.55, 95% CI:1.34-4.85) were associated with higher risks of pregnancy hypertension after adjustment for age, socioeconomic status and parity. Further adjustment for adult BMI attenuated the association for childhood overweight/obesity which was no longer statistically significant (RR = 1.28, 95% CI:0.79-2.07). The association with childhood abdominal obesity persisted after adjustment for adult WHtR (RR = 2.15, 95% CI:1.10-4.20). Compared to participants with persistently normal BMI or WHtR, those who were overweight/obese in adulthood only (RR = 1.49, 95% CI:1.10-2.02), persistently overweight/obese (RR = 2.06, 95% CI:1.29-3.29) or persistently abdominally obese (RR = 3.09, 95% CI:1.54-6.20) had increased risks of pregnancy hypertension.

Conclusion(s): Childhood adiposity was associated with increased risk of pregnancy hypertension, with the association of childhood abdominal obesity independent of adult abdominal obesity. Women who were persistently overweight/obese or abdominally obese since childhood had the highest risk of pregnancy hypertension.