Change of serum HPL level in maternal vein, umbilical cord vein and artery in mature and premature labour.

The authors examined the possible role of HPL in the onset of labour. The HPL level of the maternal vein, the umbilical cord vein and artery was compared in vaginal mature (n = 16) and premature (n = 52) deliveries. The HPL concentration was also examined in mature (n = 18) and premature (n = 18) deliveries performed by caesarean section prior to the onset of labour. The results showed that: the serum HPL level in the maternal vein, the umbilical cord vein and artery was lower during the 33rd-36th and the 40th weeks in cases of vaginal delivery compared to elective caesarean section; The artery/vein ratio decreases during labour (A/V X 100 value), indicating that HPL metabolism in the fetus decreases during regular labour pains; The onset of premature labour and delivery was associated with lower HPL levels compared to normal pregnancy. The authors assume that the lower HPL level found in cases of vaginal delivery may be due to reduced placental perfusion, but they do not exclude the possible association of lower HPL concentrations in cases of premature delivery.