CHIPS-Child: Testing the developmental programming hypothesis in the offspring of the CHIPS trial

OBJECTIVES: As a follow-up to the CHIPS trial (Control of Hypertension In Pregnancy Study) of 'less tight' (versus 'tight') control of maternal blood pressure in pregnancy, CHIPS-Child investigated potential developmental programming of maternal blood pressure control in pregnancy, by examining measures of postnatal growth rate and hypothalamic-pituitary adrenal (HPA) axis activation. METHODS: CHIPS follow-up was extended to 12 ± 2 months corrected post-gestational age for anthropometry (weight, length, head/waist circumference). For eligible children with consent for a study visit, we collected biological samples (hair/buccal samples) to evaluate HPA axis function (hair cortisol levels) and epigenetic change (DNA methylation analysis of buccal cells). The primary outcome was 'change in z-score for weight' between birth and 12 ± 2 mos. Secondary outcomes were hair cortisol and genome-wide DNA methylation status. RESULTS: Of 683 eligible babies, 183 (26.8%) were lost to follow-up, 83 (12.2%) declined, 3 (0.4%) agreed only to ongoing contact, and 414 (60.6%) consented. 372/414 (89.9%) had weight measured at 12mos. In 'less tight' (vs. 'tight') control, the primary outcome was similar [-0.26 (-0.53, +0.01); p = 0.14, p_adjusted = 0.06]; median (95% confidence interval) hair cortisol (N = 35 samples) was lower [-496 (-892, -100) ng/g; p = 0.02], and buccal swab DNA methylation (N = 16 samples) was similar. No differences in growth rate could be demonstrated up to 5 years. CONCLUSIONS: Results demonstrate no compelling evidence for developmental programming of growth or the HPA axis. Clinicians should look to the clinical findings of CHIPS to guide practice. Researchers should seek to replicate these findings and extend outcomes to paediatric blood pressure and neurodevelopment.