Apgar Scores and Oxygenation Levels: A Comparison of Vaginal and Cesarean Section Modes of Delivery

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Allison Holt and Dr. Patricia Ravert, Nursing

Abstract

Purpose
Compare Apgar scores and oxygenation levels of well infants born by Cesarean section (c-section) to those delivered vaginally.

Design
After parental consent, SpO2 levels were measured and Apgar scores and demographic data were collected from charts. Measures of central tendency were determined and means were compared with independent t-tests based on mode of birth (vaginal vs. c-section).

Sample
Sample of 321 well infants; 17.1% were born by c-section and 82.2% were born vaginally.

Main Outcome Variable
Apgar scores at one and five minutes and the oxygen saturation of two sites at two intervals (12-24 and 36-48 hours of life).

Results
T-tests revealed no statistically significant difference between c-section and vaginal births for Apgar scores and oxygenation. Further research should be conducted to not only those in well baby nursery but also those in the NICU to determine the impact of mode of birth on sample representing the entire population.

Main Text

Every year in the United States over four million babies are born. In recent years, Cesarean Sections have increased with rates surging from less than 7% in 1970 to 30.2% in 2005 (Hamilton, Martin, & Ventura, 2006). Although Cesarean section (c-section) births are medically indicated for some individuals, information regarding the effect a vaginal or c-section birth may have on an infant would be essential for those mothers considering a c-section for non-medical reasons. As a nursing student, instructors at times promote natural birth methods. This led me to question what effect different modes of birth have on the baby.

Brief literature review

The increasing rate of c-section births in the United States has caused concern and led to extensive research. In 2006, MacDorman found the rate of infant mortality to be 2.9 times higher in c-section than vaginal births. Complications such as respiratory failure and cerebral disorders may have a high rate of incidence in infants born by c-section (Kolas, Saugstad, Daltveit, Nilsen, & Oian, 2007). Respiratory Distress Syndrome, for example, is five times more likely to occur in infants born by c-section than those born by vaginal delivery (Levine, Ghai, Barton, & Strom, 2001). These complications may be due to increased fluid in the infant’s lungs after a c-section birth.

Apgar scores are widely used as a measure of neonatal health at one minute and five minutes after birth. Apgar scores continue to be a valuable assessment tool for newborns and can be used to predict mortality and neurological long-term outcome. (Casey, McIntire, Leveno, 2001). An Apgar score is determined by examining the infant for five criteria; respiration, heart rate, color, reflexes, and muscle tone. The infant is assigned a value of 0 to 2 for each criteria depending on the infant’s condition. The values are summed to determine the total Apgar score (range 0-10) with higher scores meaning a healthier infant.

Oxygen saturation (SpO2) is a reliable measure of oxygen perfusion and a tool to detect critical congenital heart defects in newborns (Meberg et al., 2008). SpO2 levels range from 40-100%. For newborns, 87-89% SpO2 is considered low (Comer, 1992). Mok, et al. (1986) found oxygen saturation is affected by the sleep state of a newborn infant. Oxygenation declines during active sleep compared to the awake state. Rosvik, Oymar, Kvaloy, & Berget (2009) studied the influence of mode of birth and birth weight on SpO2. They found SpO2 levels to actually be slightly higher for those born by c-section than those born vaginally. However, SpO2 has been found to be lower in children born at high altitude (Bakr & Habib, 2005). The purpose of this study is to compare Apgar scores and oxygenation levels (measured by pulse oximetry) of those infants born by c-section to those delivered vaginally.

Methodology

The subjects were well infants born at a regional hospital in the Intermountain West and admitted to the well baby nursery between the ages of 12-48 hours old whose parents speak English or Spanish. Newborns with symptoms of disease or requiring supplementary oxygen were admitted to the newborn intensive care unit (NICU) and therefore excluded. A parent, usually the mother, of the infant was approached in the hospital setting to obtain permission and informed consent. Once consent was granted, SpO2 levels of the right upper extremity and left lower extremity were measured using a Masimo Radical Set Monitor. Inclusion criteria for the pulse oximetry reading were as follows: a peripheral pulse rate within ten percent of the infant’s heart rate, six seconds of artifact-free wave form, and a stable value displayed for at least six seconds. Other data was collected from the patients’ charts, including gender, age, birth weight, ethnicity, mode of delivery, and Apgar scores at one and five minutes. SpO2 levels range from 40-100% with a higher percentage indicating better oxygen perfusion. Apgar scores range from 1-10 with 10 indicating the healthiest outcome.

Data analysis

Data was entered and analyzed using SPSS after collection. Measures of central tendency (means, SD, mode, etc.) were found and means for each of the quantitative data were compared with independent t-tests based on mode of birth (vaginal vs. c-section delivery). Level of significance was set at 5%.

Limitations

A limitation of this study is that the sample only included infants in the well baby nursery. Those who were taken NICU or needed other special care were excluded. This does not represent the whole population of those born vaginally or by c-section.

Results

The sample included 321 well infants. Mode of birth was not documented for two infants and they were excluded. The sample was 48.6% male and 51.4% female. The mean gestational age of the sample was 39.06 weeks and the mean birth weight was 3370 grams. Regarding mode of birth, 17.1% were born by c-section and 82.2% were born vaginally. This c-section rate is somewhat lower than the rate of 22% at the hospital as reported by the Labor and Delivery nurse manager (J. Hunter, personal communication, August 31, 2009) and significantly lower than the 2005 national rate of 30.2% (Hamilton, Martin, & Ventura, 2006). See Table 1 for complete demographical information.

The mean Apgar score for all infants was 7.96 at one minute and 8.99 at five minutes. The mean SpO2 at 12-24 hours for the right upper extremity was 96.71 and 96.27 for left lower extremity. The modes of birth were compared by birth outcomes: Apgar scores at one and five minutes and SpO2 of the infant at 12-24 hours and 36-48 hours after birth. T-tests revealed the difference between Apgar scores and oxygenation for vaginal birth and c-section birth was not significant for p

Discussion

The difference between birth outcomes for vaginal and c-section births in well babies was not found to be statistically significant. Physicians and nurses could use this information to reassure to women when a c-section section is necessary due to failure to progress, breeched position of the baby, placenta previa, or other complications.

Since this study only included those in well baby nursery, further research should be conducted to include not only those in well baby nursery but also those in the NICU or requiring other special care to determine the impact of mode of birth on sample representing the entire population. Also, those in the NICU would need to be studied to see if their required care was impacted by mode of birth. Other variables would need to be considered such as the original reason for a c-section. The complication that led to a necessary c-section may have also caused the infant to require special care. Without further study, these findings should not be used to reassure women considering c-section as a mode of delivery when there is no medical reason. For the well infants in this study, no statistically significant difference was noted in the Apgar scores or oxygenation between vaginal or c-section births.

References

  • Bakr A.F. & Babib H.S. (2005). Normal values of pulse oximetry in newborns at high altitude. Journal of Tropical Pediatrics, 51, 170-173.
  • Casey B.M., McIntire D.D., Leveno K.J. (2001). The continuing value of the Apgar score for the assessment of newborn infants. New England Journal of Medicine, 344, 467–71.
  • Hamilton B.E., Martin J.A., & Ventura S.J. (2006). Births: Preliminary data for 2007. National Vital Statistics Reports, 57(12), 1-19.
  • Kolas T., Saugstad O.D., Daltveit A.K., Nilsen S.T., Oian S.D. (2006). Planned cesarean versus planned vaginal delivery at term: Comparison of newborn infant outcomes. American Journal of Ostetrics and Gynecology, 195, 1538–1543.
  • Levine E.M., Ghai V., Barton J.J., & Strom C.M. (2001). Mode of delivery and risk of respiratory diseases in newborns. Obstetrics & Gynecology, 97, 439-442.
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