Objective <p>Cerebrospinal fluid (CSF) drainage via a ventriculoperitoneal shunt remains to be the most common treatment for infantile hydrocephalus. Since head growth is particularly dynamic and susceptible to intracranial pressure changes during the first months of life, shunting can have a considerable impact. This study aimed to examine changes in head circumference and ventricular width and evaluate their interdependence in children who underwent shunting during infancy with either of two different adjustable valve regimens.</p> Methods <p>We conducted a retrospective analysis on synchronized patient databases at two tertiary pediatric neurosurgical centers. One center implanted a differential pressure (DP) adjustable valve with a fixed gravitational unit (aDP_G group). The other center used an adjustable gravitational assistance (GA) valve combined with a fixed DP unit (aG_DP group). We included infants less than 2 years of age at shunt implantation with a follow-up time of 3 years, respectively. Patient demographics, head circumferences (<i>z</i>-scores), ventricular width and opening pressure settings of the shunt valves were collected and compared using statistical tests as appropriate.</p> Results <p>A total of 155 infants (<i>n</i> = 78 in aDP_G group and <i>n</i> = 77 in the aG_DP group) could be included in this study. Changes in head circumference <i>z</i>-scores across follow-up time were similar in both groups (<i>p</i> = 0.99). In the aG_DP group, patients had more pronounced pathologically enlarged ventricles measured by fronto-occipital horn ratio (FOHR) at implantation compared to the aDP_G group (<i>p</i> = 0.037). At the end of follow-up, in both groups, the proportion of patients showing a normal FOHR (0.37 ± 0.026) increased significantly, while reduction in ventricular size over time was more pronounced in the aG_DP group (<i>p</i> &lt; 0.01). The valve setting in the aG_DP group was&#xa0;significantly lower in standing and in lying position compared to the aDP_G group. Regression analysis revealed a significant association between the change in median FOHR and head circumference at the end of follow-up (slope (95%CI) = 3.46 (2.42–4.49), <i>R</i>² = 0.22, <i>p</i> &lt; 0.0001). Median change in FOHR, as well as head circumference at the end of follow-up, did correlate to valve settings at shunt implantation&#xa0;(p&lt;0.01).</p> Conclusions <p>The present study demonstrates a strong relation between changes in median FOHR and head circumference at the end of follow-up in shunted hydrocephalic infants. In addition, we identified a direct influence of initial valve setting on changes of ventricular width and&#xa0;head circumference at follow-up, underlining the importance of&#xa0;valve resistance for regulating&#xa0;CSF diversion and its anatomical consequences. Further investigations are needed to assess the influence of these parameters on long-term neurodevelopment and functional outcome.</p>