Association of hemoglobin and spontaneous closure of the ductus arteriosus during the transitional period in very low birth weight infants.

OBJECTIVES To determine the association between plasma hemoglobin (HB) at three time-points (birth, postnatal days 0-3 and 0-10) and spontaneous closure of the ductus arteriosus (sDAC). STUDY DESIGN A retrospective case-control study of preterm infants born (2013-2016) between 24 and 29 weeks of gestational age (GA) was conducted in a level three perinatal center in Switzerland. We collected hemoglobin at birth, between days 0-3 and 0-10 in two distinct groups: (i) patients treated for a PDA and (ii) patients with spontaneous closure of the ductus arteriosus (sDAC). Antenatal and postnatal demographic data and neonatal morbidity were collected. Bivariate analysis was performed and a stepwise logistic regression was done to investigate factors associated with sDAC. RESULTS We reviewed the medical chart of 184 premature infants of whom 146 (79.3%) satisfied eligibility criteria. Of these, 74 (51%) were classified as sDAC. Patients with sDAC were older (GA: 28 vs 27, p <  0.001), more stable (clinical risk index for babies score (CRIB score): 2 vs 5, p <  0.001) and had better clinical outcomes than patients who received treatment for a PDA. Infants in the sDAC group had a higher level of hemoglobin during the first ten postnatal days. Multiple logistic regression analysis revealed that lower HB level (day 0-10) were associated with failure of sDAC (p <  0.05). CONCLUSIONS This is one of the first studies to highlight a potential association between hemoglobin during the transitional period and sDAC. The biological nature of this observation requires prospective clarification.