Use of Near-Infrared Spectroscopic Analysis of Second Trimester Amniotic Fluid to Assess Preterm Births

Table 3

Means and standard deviations by functional groups for term and preterm births^a.

Functional group ratios	Gestation period^b
	Preterm < 35 weeks^c	Term ≥ 37 weeks
NH/CH*	3.49 ± 0.5	3.43 ± 0.8
NH/ROH^†	2.38 ± 0.3	2.36 ± 0.4
CH/ROH^‡	0.69 ± 0.0	0.69 ± 0.0
NH/H2O^§	2.28 ± 0.2	2.29 ± 0.2
CH/H2O^¶	0.67 ± 0.1	0.69 ± 0.1

^aData are reported as means ± standard deviation. Birth outcomes and second trimester amniotic fluid functional groups ratios for mothers delivering in term (n = 216) and preterm (n = 10).
^bAll the differences between term and preterm groups were nonsignificant at a confidence level of 10%, with the exception of NH/CH which had a P value of 0.090.
^cIt is important to mention that one sample that had a gestational age of 35.1 was discarded as an outlier. Its exclusion from this ratio analysis was primarily because it had a gestational age 2 weeks above the mean and also was 500 g heavier than the average of the group. *Relative amount of protein to carbohydrates/fats. ^†Relative amount of protein to modified polyalcohols.^‡Relative amount of carbohydrates/fats to modified polyalcohols. ^§Relative amount of protein to water. ^¶Relative amount of carbohydrates/fats to water.