Luiz H. Meneghin and Dr. Debra Hobbins, Nursing
Sudden Infant Death Syndrome (SIDS), also called crib death, refers to the sudden, unexpected death of any infant or young child in whom a postmortem examination fails to demonstrate a cause for death. It is the greatest single cause of death among infants between 1 week and 1 year of age.1 Many studies have identified risk factors associated with SIDS (low birth weight, preterm delivery, maternal smoking, winter months, positioning during sleep, male gender, etc.), however, no studies were found regarding the method of birth and the incidence of SIDS. The purpose of this study was to investigate the correlation between a specific method of birth and the incidence of SIDS.
Initially, the plan was to examine the SIDS-related deaths that had occurred during the past ten years in an effort to collect sufficient data for use in correlational studies. The names of the children who had died from SIDS would be obtained from medical records kept in hospitals and clinics. Once identified, the birth records of those infants would be used to determine the birth method utilized. However, upon contacting the State Department of Health later in the project, we were informed that such information was confidential and could not be obtained.
Understanding the importance of the project, Dr. Barry E. Nangle, director of the Bureau of Vital Records, was willing to help with the gathering of the needed information. The assessment of the data was complicated and laborious because the information pertinent to births and deaths were entered in separate files. As a result of Dr. Nangle’s cooperation, the report “Matched Births by Year of Birth of Children Who Died of Sudden Infant Death Syndrome” was obtained. The report supplied information about 49 cases of SIDS that had occurred in Utah in 1992. The information obtained from that document is presented in Table 1.
The information obtained favors the hypothesis that fetal asphyxia (hypoxemia) is possibly an aspect that needs further investigation and analysis to determine if it is a major factor linked to the occurrence of SIDS. Fetal distress may occur early or late depending on which stage of labor is prolonged. Uteroplacental perfusion may be impeded by the length of the labor, resulting in asphyxia or a generalized, inadequate supply of oxygen to body cells2. All 49 cases of SIDS were related to vaginal birth. According to Dr. Nangle, about 17% of the births in Utah are the result of cesarean sections. Once this percentile is not verified in the number of cases studied, it is reasonable to infer that hypoxemia might be associated with the occurrence of SIDS. Further research and a much larger sample should be considered to corroborate this hypothesis.
The process of respiration is controlled by chemoreceptors. There are central chemoreceptors, which are located in the brain, and peripheral chemoreceptors located in the aorta and carotid arteries. These structures are sensitive to carbon dioxide and oxygen concentrations in the blood and send signals to the respiratory center to increase the depth and rate of respiration. Depending on certain circumstances, the stimulus to breathe may be lost resulting in apnea or cessation of breathing.
This study suggests that further investigation be conducted in order to determine if fetal hypoxemia during the birth process interferes with the mechanism that controls respiration creating a pre-set condition in which an elevated level of carbon dioxide in the blood would trigger the cessation of breathing. This hypothesis is further substantiated by the fact that many of the risk factors so far identified for the occurrence of SIDS have influence or are related to respiratory aspects. However, a larger sample of SIDS cases should be evaluated in order to support the hypothesis of fetal asphyxia as a major factor related to the incidence of SIDS. Positive correlation would further support a more detailed and scientific study regarding a possible unknown mechanism that would be triggered by low levels of oxygen and/or elevated levels of carbonic gas in the infant’s blood. This would cause a suppression of the normal respiratory control mechanisms leading to cessation of respiration and subsequent death.
Table I – Cases of SIDS by Birth Method
Vaginal Births 49 cases
Cesarean sections 0 cases
Total 49 cases
References
- McCance, K.L. and S.E. Huether. 1994. p. I] 97. In: Pathophysiology – The Biologic Basis for Disease in Adults and Children. Mosby, St. Louis.
- Olds, S.B., M.L. London, and P.W. Ladewig. 1992. pp. 732-733,1006-1007. In: Maternal- Newborn Nursing. Addison-wesley Nursing, Redwood City, CA.
- Ibid. pp. II 35-1137, 1169.