Sucking Problems

The suck reflex is one of the first and most primitive responses that an infant has to oral stimulation. When the lips or cheek are tickled, the muscles coordinate to form a suck response so that the child can suck and coordinate the muscles needed to ingest milk.

The reflex to suck forms sometime in the 6-8th month of gestation (pregnancy). The ability to coordinate the suck and swallow (to be able to ingest milk) forms approximately in the last 2 months before a full term birth. Babies born prematurely, that don’t have the last few months to develop before birth, may not have this reflex and may need help to feed until the reflex develops. This help may include a tube from the nose into the stomach to deliver milk. It can take weeks for a premature infant to gain the endurance to take all feeds by themselves. Premature infants are usually close to their expected due date by the time they figure out how to suck and swallow on their own.

While premature infants may have a reason for poor sucking reflexes, in full term children and older infants, the reflex should be present. Even in children with spinal cord injuries, the sucking reflex is typically preserved.1 Thus, since this reflex is present even in the face of neurological injury, in full term children with sucking problems, this could indicate larger, significant neurological problems. Studies have shown that infants with poor or absent suck reflex usually have moderate or significant perinatal hypoxic ischemic encephalopathy (lack of oxygen around the time of birth).2 Please note that true hypoxic ischemic encephalopathy is defined as US standards and is much different than the terms used indiscriminately in many Eastern European referrals. Multiple congenital syndromes are associated with poor suck reflex usually noted shortly after birth.

Age at the time of referral is important when considering the diagnosis of sucking problems. If the child is still quite young and there aren’t many milestones to go by yet, then the child with sucking problems has a number of risks for their future potential. In an older child with a history of sucking problems, if the issues have resolved and the child is thriving, there would be minimal concerns at that point regarding the child’s long term potential.


Suck reflex: A basic and primitive reflex that should be present in all neurologically normal infants. A wide spectrum but the severe forms are the ones likely to be mentioned on a preadoption referral
Ability to suck and coordination may be poor in premature children
Can also be a sign of brain damage and/or syndrome that may limit the child’s future potential.


  1. Lanska MJ, Roessmann U, Wiznitzer M. Magnetic resonance imaging in cervical cord birth injury. Pediatrics. 1990;85(5):760. 
  2. Caravale B, Allemand F, Libenson MH. Factors predictive of seizures and neurologic outcome in perinatal depression. Pediatr Neurol. 2003;29(1):18-25.


Your feedback is important to us!  

Please take a moment to fill out this survey about Health Topics for Preadoptive Parents


Book Author

Judith K. Eckerle, M.D. 
Director, Adoption Medicine Clinic
Assistant Professor of Pediatrics


Kristin C. Voos, MD
Assistant Professor, University of Missouri-Kansas City School of Medicine
Division of Neonatology
Children’s Mercy Hospitals and Clinics

Provide feedback on this chapter