Changes in Pepsinogen Activity in Biological Fluids of Pregnant Women with Newborns of Different Weights

Background: The main “peptic” cells of the gastric glands provide the body’s only source of pepsinogen synthesis and incretion. Small amounts of endogenously supplied pepsinogen in biological fluids play an important role in anabolic processes in the mother and newborn. The aim: This work aimed to analyze the dynamics of pepsinogen activity in the blood serum, saliva, urine, and coprofiltrate in pregnant women in each trimester of pregnancy and in the postpartum period, taking into account the body weight of the newborn—normal weight, underweight, and overweight. Methods: Data from studies involving non-pregnant (n = 45) and pregnant (n = 152) women with newborns with different weights were analyzed. There were 86 women with a normal-weight newborn, 34 women with an underweight newborn, and 32 women with an overweight newborn. Total proteolytic activity in biological fluids was determined using the spectrophotometric tyrosine (tyr) Kunitz–Northrop method modified by Korot’ko. A 2% solution of dry plasma was used as a substrate. Outcomes: In non-pregnant women, the blood proteolytic activity was 58.1 ± 1.4 tyr U/mL, and saliva at 1520.9 ± 112.2 tyr U/mL, urine at 4520.3 ± 154.3 tyr U/mL, and coprofiltrate at 442.2 ± 20.5 tyr U/mL. We established that the pepsinogen activity during pregnancy is distributed unevenly, taking into account the body weight of the newborn, and changes significantly in women with an underweight or overweight newborn. Conclusions: Pepsinogen homeostasis in pregnant women is maintained by renal and extrarenal pathways, and an important role is played by the salivary glands, with the most significant changes occurring in women with overweight and underweight newborns.