[Study on the relationship between endogenous opioid peptides and fetal distress].

Objective: To evaluate the role of endogenous opioid peptides (EOP) in the fetal distress.

Methods: Forty three patients with fetal distress (fetal distress group) and 40 healthy pregnant women (control group) in their third trimester were studied. The concentrations of plasma EOP (beta-endorphin, dorphin A(1 - 13) and leu-enkephalin) were measured by radioimmunoassay. Umbilical artery pH, PO(2) and PCO(2) were also measured.

Results: The levels of umbilical artery plasma EOP (beta-endorphin, dorphin A(1 - 13) and leu-enkephalin) in fetal distress group were (453 +/- 68) ng/L, (242 +/- 33) ng/L, and (498 +/- 68) ng/L, respectively. In control group, the levels of EOP were (251 +/- 39) ng/L, (103 +/- 22) ng/L, and (322 +/- 40) ng/L, respectively. The levels of umbilical artery plasma EOP (beta-endorphin, dorphin A(1 - 13) and leu-enkephalin) in fetal distress group were significantly higher than that in the control group (P < 0.01,P < 0.05). The umbilical artery blood gas analysis: pH was (7.0 +/- 0.1), PO(2) was (1.7 +/- 0.6) kPa, PCO(2) was (8.9 +/- 0.7) kPa; the levels of beta-endorphin and dorphin A(1 - 13) were negatively correlated to pH and PO(2) in umbilical artery plasma (P < 0.01; P < 0.05), significant correlation was found between the EOP and PCO(2) (P < 0.05). In fetal distress group, the levels of maternal plasma EOP were (40 +/- 13) ng/L, (64 +/- 16) ng/L and (219 +/- 40) ng/L respectively. In control group, the levels were (37 +/- 9) ng/L, (59 +/- 15) ng/L and (199 +/- 37) ng/L respectively. There was no statistical difference in the levels of maternal plasma EOP between the control group and fetal distress group (P > 0.05).

Conclusions: The fetal distress was associated with EOP, the changes of EOP levels in umbilical artery plasma may play an important role in the pathophysiological changes in fetal distress.