Causes of cot death

There are no known causes of crib death. The deaths are usually thought to be a combination of factors.

According to researchers, cot death, also known as Sudden Infant Death Syndrome (SIDS), occurs at a particular stage in a baby’s development when they are vulnerable to environmental stresses.

Environmental stresses

Environmental stresses include exposure to tobacco smoke.

Maternal smoking during pregnancy raises risk of SIDS four fold and exposure to environmental smoke at home raises risk of SIDS eight fold in babies.

Risk factors associated with cot deaths

Some reasons and risk factors associated with cot deaths or SIDS include stomach sleeping, brain abnormalities and so forth. (1-5)

Stomach sleeping

Foremost among risk factors is stomach sleeping.

There are numerous studies that show that babies placed on their stomachs to sleep are at greater risk of SIDS than those sleeping on their backs or sides.

This could be because the stomach sleeping puts pressure on a child's jaw and interferes with normal breathing.

In addition, the baby could be "rebreathing" his or her own exhaled air.

This could be true particularly in a soft bed with bedding, pillows etc.

There is creation of a soft space around the baby's mouth that traps exhaled air. Since this air is poor in oxygen and rich in carbon dioxide the baby may die of lack of oxygen.

Brain abnormalities

Abnormality in the arcuate nucleus, a part of the brain that may help control breathing and awakening during sleep, may contribute to SIDS.

Normally if there is lack of oxygen in breathed air the baby responds by waking up and crying. This also changes the breathing and heart rate and makes up for the oxygen lack.

In babies with a problem in the arcuate nucleus this reaction of waking up is lost raising risk of SIDS.

Other risk factors

Other risk factors include:

  • Babies born prematurely
  • Low birth weight infants
  • Age less than six months. Cribs deaths are less common in the first month after birth. Most deaths due to SIDS occur between 2 and 4 months of age. Beyond one year the risk is low. The incidence increases during cold weather.
  • Ethnicity - African-American infants are twice as likely and Native American infants are nearly three times more likely to die of crib death than Caucasian infants.
  • Gender – Male babies are more at risk of SIDS.
  • Getting tangled in bedding or clothing – This leads to suffocation and death of the baby. Often the parent or adult sleeping with the infant may be under the influence of drugs or alcohol. The baby may be suffocated by a hand or a pillow over its face.
  • Breathing obstruction in the baby due to a birth condition or a minor illness.
  • Babies who die of SIDS may also have problems regulating their heart rate, breathing and temperature in response to environmental stresses.
  • Young mothers, mothers who have had poor pregnancy care are other risk factors for SIDS
  • Overheating of the baby from excessive sleepwear and bedding may raise risk of SIDS.
  • Those with a sibling who died of SIDS may be at a higher risk of SIDS.
  • Other causes of SIDS include poisoning or overdoses of drugs, heart defects, metabolic errors or diseases and infections.

Further Reading

Last Updated: May 31, 2019

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


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