Cord Blood Haptoglobin, Cerebral Palsy and Death in Infants of Women at Risk for Preterm Birth: A Secondary Analysis of a Randomised Controlled Trial

Abstract

Background: Antenatal exposure to intra-uterine inflammation results in precocious Haptoglobin (Hp) expression (switch-on status). We investigated the relationships between foetal Hp expression at birth with newborn and childhood outcomes.

Methods: We evaluated cord blood samples from 921 newborns of women at imminent risk for preterm delivery randomised to either placebo (n = 471, birth gestational age (GA) median [min-max]: 31 [24-41] weeks) or magnesium sulphate (n = 450, GA 31 [24-42] weeks]). Primary outcome was infant death by 1 year and/or cerebral palsy (CP) ≥ 2 years of corrected age. Adjusted odd ratios (aOR) for neonatal and childhood outcomes were calculated controlling for GA, birth weight, sex, and magnesium exposure.

Findings: Primary outcome occurred in 2.8% of offspring. Newborns were classified in three pre-defined categorisation groups by cord blood Hp switch status and IL-6 levels: inflammation-nonexposed (Category 1, n = 432, 47%), inflammation-exposed haptoglobinemic (Category 2, n = 449, 49%), and inflammation-exposed anhaptoglobinemic or hypohaptoglobinemic (Category 3, n = 40, 4%). Newborns, found anhaptoglobinemic or hypohaptoglobinemic (Category 3) had increased OR for intraventricular haemorrhage (IVH) and/or death (aOR: 7.0; 95% CI: 1.4-34.6, p = 0.02) and for CP and/or death (aOR: 6.27; 95% CI: 1.7-23.5, p = 0.006) compared with Category 2. Foetal ability to respond to inflammation by haptoglobinemia resulted in aOR similar to inflammation-nonexposed newborns. Hp1-2 or Hp2-2 phenotypes protected against retinopathy of prematurity (aOR = 0.66; 95% CI 0.48-0.91, p = 0.01).

Interpretation: Foetal ability to switch-on Hp expression in response to inflammation was associated with reduction of IVH and/or death, and CP and/or death. Foetuses unable to mount such a response had an increased risk of adverse outcomes.Trial Registration: clinicaltrials.gov Identifier: NCT00014989.

Keywords: Cerebral palsy; Haptoglobin; Magnesium; Preterm birth.

Fig. 1

CONSORT flow diagram with enrolment, randomisation and distribution of the mothers and infants whose cord blood samples were analysed in this study (n = 921). *Secondary outcomes: intraventricular haemorrhage (IVH) grades 3 or 4, retinopathy of prematurity, necrotizing enterocolitis, patent ductus arteriosum, proven neonatal sepsis, seizures and bronchopulmonary dysplasia; ^†Primary outcome: infant death by 1 year of life and/or CP (all levels) at or beyond 2 years of corrected age; ^‡Secondary outcomes: seizures, mental developmental delay index < 70, psychomotor delay index < 70.