A meconium plug causing intestinal obstruction is usually benign and clears after rectal stimulation or contrast enema. If regular bowel movement does not occur afterwards, a rectal biopsy is recommended to look for Hirschprung’s disease. Meconium plug syndrome is not the same as meconium ileus (associated with cystic fibrosis).
Reference: Keckler, S. J., Peter, S. D. S., Spilde, T. L., Tsao, K., Ostlie, D. J., Holcomb, G. W., & Snyder, C. L. (2008). Current significance of meconium plug syndrome. Journal of Pediatric Surgery; 43(5): 896-898.