Total hemoglobin concentration in amniotic fluid is increased in intraamniotic infection/inflammation

Abstract

Objective-Discolored amniotic fluid (AF) has been associated with intra-amniotic infection/ inflammation (IAI) in patients with preterm labor (PTL). The presence of hemoglobin and its catabolic products have been implicated as a cause for AF discoloration. The aim of this study was to determine whether there is an association between total hemoglobin concentration in AF and gestational age, spontaneous labor (term and preterm) and the presence or absence of IAI.Study design-This cross-sectional study included patients in the following groups: 1) midtrimester (n=65); 2) term not in labor (n=22); 3) term in labor (n=47); 4) spontaneous PTL who delivered at term (n=92); 5) PTL without IAI who delivered preterm (n=76); 6) PTL with IAI (n=81); 7) preterm prelabor rupture of the membranes (PPROM) with IAI (n=48); and 8) PPROM without IAI (n=49). Total hemoglobin concentrations in amniotic fluid were determined by an enzyme-linked immunoassay. Non-parametric statistics were used for analysis. Results-1)Hemoglobin was detected in all AF samples (n=480); 2) The median AF total hemoglobin concentration at term was significantly higher than in mid-trimester [520.6 ng/mL, interquartile range (IQR) 271.2-1549.2 vs. 58.5 ng/mL, IQR 26. 1-200.8; p<0.001]; 3) Among patients with PTL, the median AF total hemoglobin concentration was significantly higher in patients with IAI than in those without IAI (4671.8 ng/mL, IQR 1294.2-8620.7 vs. 2013.6 ng/mL, IQR 629.2-5420.4; p=0.01) or women who delivered at term (1143.4 ng/mL, IQR 451.8-4037.9; p=0.001); 4) Similarly, among patients with PPROM, the median AF total hemoglobin concentration was significantly higher in patients with IAI than in those without IAI (10753.7 ng/mL, IQR 2053.9-56026.6 vs. 2281 ng/mL, IQR 938.2-9191.7; p=0.02); 5) Women at term in labor had a higher median hemoglobin concentration than those not in labor (1952.6 ng/mL, IQR 709.6-6289.2 vs. 520.6 ng/ mL, IQR 271.1-1549.2; p=0.003).

A molecular signature of an arrest of descent in human parturition

“…Indeed, the most enriched biological pathway is “cytokine-cytokine receptor interaction”, followed by the “complement and coagulation cascade”, which we and others have reported plays a key role in the activation of an inflammatory response 139141;142;145;147;151;155-160;194-203 Moreover, significantly enriched biological processes such as “inflammatory response”, “chemotaxis” and molecular functions such as “chemokine activity” further support a role for inflammation in this labor disorder.…”

Amniotic fluid fetal hemoglobin in normal pregnancies and pregnancies complicated with preterm labor or prelabor rupture of membranes

“…[6] In order to study the origin of the hemoglobin detected,[6] the percentage of fetal hemoglobin of the total hemoglobin was calculate in each sample, and the following results were found: 1) the median amniotic fluid fetal hemoglobin percentage of the total hemoglobin concentration was lower in women at term in labor than those not in labor (0.2%, IQR 0–1.1 vs. 2.2%, IQR 0–7.1; p =0.03); 2) the median amniotic fluid fetal hemoglobin percentage of the total hemoglobin differed significantly among the 3 groups of patients with spontaneous PTL (Kruskal-Wallis, p =0.001). Women with PTL and IAI had a lower median amniotic fluid fetal hemoglobin percentage of the total hemoglobin than those without IAI who delivered preterm (2.8%, IQR 1.2–7.4 vs. 5.6%, IQR 1.8–13.5; p =0.03) and than those with PTL who delivered at term (7.3%, IQR 3–15.4; p <0.001) (Figure 4).…”

“…This is in contrast to the increased amniotic fluid total hemoglobin concentrations in pregnancies complicated with IAI. [6] This observation suggests that the main source of fetal hemoglobin in cases of PTL with IAI is of maternal origin, and the detected fetal hemoglobin represents the normal percentage of hemoglobin F in the maternal blood. Indeed, Gomez et al[7] proposed that a sub-clinical intrauterine infection can cause deciduitis and decidual bleeding leading to the clinical manifestation of vaginal bleeding and subsequent adverse pregnancy outcomes.…”

“…Indeed, we recently reported that IAI is associated with elevated median amniotic fluid total hemoglobin concentration in patients with spontaneous preterm labor and intact membranes (PTL), as well as in those with preterm prelabor rupture of membranes (preterm PROM). [6] However, it is unclear if the origin of the detected hemoglobin is maternal or fetal.…”

“…Thus, we hypothesized that the main origin of amniotic fluid hemoglobin detected in pregnancies complicated with IAI, as well as in those with spontaneous labor at term is of maternal origin. [6] Indeed, less than 1% of the hemoglobin in the normal adult corresponds to the fraction of hemoglobin F (α 2 γ 2 ), also known as fetal hemoglobin,[8,9] whereas in the fetal circulation the majority of hemoglobin is hemoglobin F.[9] Therefore, determination of fetal hemoglobin concentrations in amniotic fluid can assist in determining the origin of the total hemoglobin in the amniotic cavity. [6]…”