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

Allison Holt
Patricia Ravert*
Brigham Young University


Abstract

This study compared Apgar scores and oxygenation levels of well infants born by Cesarean section (c-section) to those delivered vaginally. T-tests in a sample of 321 well infants (17.1% c-section deliveries and 82.2% vaginal deliveries) revealed no statistically significant difference between c-section and vaginal births for Apgar scores and oxygenation.

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 percent in 1970 to 30.2 percent 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 percent. For newborns, 87-89 percent 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 were 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 percent with a higher percentage indicating better oxygen perfusion. Apgar scores range from 1-10 with 10 indicating the healthiest outcome.

Data analysis. Data were 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 percent.

Limitations. A limitation of this study is that the sample only included infants in the well baby nursery. Those who were taken to 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 percent male and 51.4 percent 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 percent were born by c-section and 82.2 percent were born vaginally. This c-section rate is somewhat lower than the rate of 22 percent 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 percent (Hamilton, Martin, & Ventura, 2006). See Table 1 for complete demographic 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<0.05. See Tables 2 and 3 for complete statistics.

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 women when a c-section section is necessary due to failure to progress, breeched position of the baby, placenta previa, or other complications.

Because 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 need to be studied to see if their required care was impacted by mode of birth. Other variables 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 Obstetrics 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.

MacDorman, M. F., Declercq, E., Menacker ,F., & Malloy, M. H. (2006) Infant and neonatal mortality for primary Caesarean and vaginal births to women with ‘no indicated risk,’ United States, 1998–2001 birth cohorts. Birth 33,175–182.

Meberg, A., Andreassen, A., Brunvand, L., Markestad, T., Moster, D., Nietsch, L., et al. (2009). Pulse oximetry screening as a complementary strategy to detect critical congenital heart defects. Acta Paediatrica, 98, 682-686.

Mok, J. Y., McLaughlin, F. J., Pintar, M., Hak, H., Amaro-Galvez, R., & Levison, H. (1986). Transcutaneous monitoring of oxygenation: what is normal? Journal of Pediatrics, 108(3), 365-71.

Røsvik, A., Øymar, K., Kvaløy, J.T., & Berget ,M. (2009). Oxygen saturation in healthy newborns; influence of birth weight and mode of delivery. Journal of Perinatal Medicine, 37 (2009), 403-406.


Table 1.
Demographics (n=319)

Item

Vaginal (n=261)

Cesarean Section (n=55)

Total

Gender

 

 

 

M

122

31

154

F

139

23

163

Ethnicity

 

 

 

Asian

3

1

4

African American

1

0

1

Hispanic or Latino

59

15

75

Native Hawaiian or Pacific Islander

2

0

2

White/Caucasian

197

39

237

Note. The total for gender is not equal to the sum of the vaginal and cesarean count since gender was not documented for two infants


Table 2.
Independent t Tests of Apgar Scores (1 minute and 5 minute) by Mode of Delivery (Vaginal and C-section) 

Item

n

M

SD

t

P

Apgar 1 Minute

 

 

 

-.082

.935

Vaginal

263

7.97

.728

 

 

C-section

55

7.98

.490

 

 

Apgar 5 Minute

 

 

 

.626

.532

Vaginal

263

8.99

.376

 

 

C-section

55

8.96

.189

 

 


Table 3.
Independent t Tests of Oxygenation Levels (12-24 hours and 36-48 hours) by Mode of Delivery (Vaginal and C-section) 

Item

N

M

SD

t

P

RUE 12-24 hours

 

 

 

1.356

.176

Vaginal

245

96.78

2.04

 

 

C-section

54

96.37

1.73

 

 

LLE 12-24 hours

 

 

 

-.716

.475

Vaginal

259

96.22

2.05

 

 

C-section

55

96.44

1.73

 

 

RUE 36-48 hours

 

 

 

-.172

.864

Vaginal

66

96.15

1.72

 

 

C-section

27

96.22

1.99

 

 

LLE 36-48 hours

 

 

 

-.832

.408

Vaginal

66

96.00

1.65

 

 

C-section

27

96.33

2.00

 

 

Note. RUE=Right upper extremity, LLE=Left lower extremity

 


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