Urinary Neopterin Levels in the Different Stages of Pregnancy

Abstract

Background/Aims: Neopterin is a biochemical marker of activated cell-mediated immune response which increases in pathological conditions associated with cellular immune activation as well as in pregnancy where cellular immune response is predominant. The aim of this study was to determine the urinary neopterin level in each trimester of pregnancy and to determine if it can be used as a marker. Methods: 104 healthy pregnant women (mean age 22.10 ± 4.39 years; 36 in the first, 30 in the second and 38 in the third trimester) and 16 non-pregnant healthy women (mean age 20.94 ± 4.48 year) were included. Results: The mean urinary neopterin concentration of all pregnant women was higher than that of non-pregnant women (166.4 ± 31.7 and 103.1 ± 27.5 µmol/mol creatinine respectively, p < 0.01). The mean urinary neopterin levels in each trimester and non-pregnant women were 139.8 ± 49.6, 131 ± 40.2, 227.9 ± 86.5 and 103.1 ± 27.5 µmol/mol creatinine, respectively. Urinary neopterin levels were not significantly different between non-pregnant, first and second trimester groups, but were significantly higher in the third trimester than each of these groups (p < 0.05, p < 0.01 and p < 0.01 respectively). Conclusion: Urinary neopterin levels increase significantly in the third trimester probably due to more predominated cellular immunity. The pathologies causing cellular immune activation, especially in the first two trimesters can be predicted with urinary neopterin levels.

Modulation of cell-mediated immunity during pregnancy in wild bonobos

“…Seven out of nine females (for one female we lacked post-pregnancy samples) had higher neopterin levels in the third trimester as compared to after the pregnancy, but only five females had higher third trimester neopterin levels than before the pregnancy. In human studies, substantial variation in neopterin level has also been reported in both blood and urine [32,33,35]. One study provided individual trajectories of neopterin levels within women [45], revealing similar patterns as in our results.…”

“…Other pairwise comparisons did not indicate differences between conditions (electronic supplementary material, S1 and table S3). Likewise, human studies noted highest neopterin levels in urine and blood during the last trimester of pregnancy [32][33][34][35]37]. This pattern has been attributed to different inflammatory states in pregnancy.…”

“…Another explanation is that our method of dating pregnancies from the day of birth may have led to misassignments, potentially categorizing some samples as 'before pregnancy' when the female was already pregnant, leading to higher mean neopterin levels before pregnancy. In this context it is difficult to compare with humans, because usually participants are not sampled before pregnancy, and studies use distinct cohorts of non-pregnant and pregnant females [33,45,57]. Despite differences in study design, one human study found that neopterin levels did not differ in samples from women in the first and second trimester from levels measured in samples from non-pregnant women [33], which is in line with our own results where neopterin levels before pregnancy were not significantly different from levels in the first and second trimester of pregnancy.…”

“…In this context it is difficult to compare with humans, because usually participants are not sampled before pregnancy, and studies use distinct cohorts of non-pregnant and pregnant females [33,45,57]. Despite differences in study design, one human study found that neopterin levels did not differ in samples from women in the first and second trimester from levels measured in samples from non-pregnant women [33], which is in line with our own results where neopterin levels before pregnancy were not significantly different from levels in the first and second trimester of pregnancy. We found that on the individual level, patterns of urinary neopterin levels across pregnancy phases differed substantially (figure 1b).…”

“…In humans, neopterin is used to track maternal immune responses and shifts in immunity during pregnancy. In blood and urine samples, neopterin levels were consistently elevated in pregnant women compared to their non-pregnant peers, with highest levels observed during the third trimester, followed by a decline postpartum [32][33][34][35][36][37]. Neopterin results in pregnant non-human primates are inconsistent.…”