Serum and urine levels of activin A in primigravidae and multigravidae: a prospective cross-sectional study

The aim of the present study was to investigate serum and urine levels of activin A in different moments of gestation, in primigravidae and in multigravidae, to understand whether these variables (biological sample and first gestation) affect activin A as a biomarker in pregnancy. We prospectively included 43 pairs of serum and urine samples from 25 women examined at different gestational ages (range 45 to 268 days). In the group of primigravidae (n = 16 samples from 9 participants), there was no significant change in serum activin A levels across gestation. Conversely, the group of multigravidae (n = 27 samples from 16 women) had higher serum activin A levels in the third trimester (2676 +/- 840 pg/ml) compared to the first (583 +/- 408 pg/ml) and second (1040 +/- 384) trimesters (p = .025). Urine activin A concentrations did not differ between the two groups and did not change according to the gestation phase. There was no correlation between serum and urinary levels of activin A (r = 0.149, p = .359). These data suggest that activin A secretion may vary less during the first pregnancy, while urine activin A is unlikely to be a surrogate for the systemic levels of this hormone in pregnant women.

Automated summary

This study aimed to investigate the levels of activin A in serum and urine during different moments of gestation in primigravidae and multigravidae. The results showed that activin A levels in serum were significantly higher in the third trimester for multigravidae compared to the first and second trimesters, while there were no significant changes in primigravidae. Urine activin A concentrations did not differ between the two groups and did not change throughout gestation, suggesting that urine activin A may not be a reliable indicator of systemic hormone levels in pregnant women.