To evaluate the relationship between multichannel intraluminal impedance and pH monitoring (MII/pH) values in newborns with symptoms of gastroesophageal reflux disease (GERD) and clinical history in their first 3 years of life.

Sixty-four newborns with GERD symptoms who underwent MII/pH in the first weeks of life were enrolled into a clinical follow-up program. Follow-up visits were programmed at 1, 3, 6, 9, 12, 18, 24, and 36 months. Patients were divided into 3 groups according to duration of symptoms: short (1-3 months), medium (4-9 months), and long (>9 months), and MII/pH values in these groups were compared.

Fifty-three patients completed the 3-year follow-up. The number of patients with GERD symptoms decreased each month. A comparison of MII/pH values of the 3 lifetime symptom groups revealed differences in the impedance bolus exposure index (F = 83; P = .012) and proximal reflux frequency (F = 410; P = .022). These 2 MII variables showed an increasing trend from the short lifetime symptom group to the long lifetime symptom group. Weakly acidic reflux events, but not acidic events, were responsible for these differences.

MII/pH in newborns has prognostic value regarding the duration of GERD symptoms and provides useful information that clinicians may give parents about the prognosis of symptomatic infants. Impedance bolus exposure index and proximal reflux frequency seem to be the variables with the highest predictive value. Weakly acidic reflux events play an important role in determining the duration of GERD symptoms in newborns.