[Influence of interleukin-1 and interleukin-6 on modulation of hypothalamo-pituitary-adrenal axis in pregnancy at term and in spontaneous and oxytocin-induced delivery].

Objectives: During the pregnancy the placenta and hypothalamus produce trophic hormones for hypothalamo-pituitary-adrenal axis (HPA), i.e. corticotropin releasing hormone (CRH) and adrenocorticotropin (ACTH). The HPA axis of pregnant women is differentially modulated in comparison to non-pregnant ones. Beside steroids, the influence on CRH release may be modulated by cytokines, especially interleukin 1 (IL-1) and interleukin 6 (IL-6).

Design: To evaluate the effects of IL-1 and IL-6 on modulation of HPA axis in pregnancy, we have examined the group of women with spontaneous delivery, and second group consists of women delivered after intravenous oxytocin infusion. All women were at term and in the same pregnancy age.

Material And Methods: Blood was sampled from a maternal peripheral vein days before labour, during the second stage of labour and on the second postnatal day, the levels of IL-1, IL-6, CRH, ACTH and cortisol were measured. The concentrations of hormones were measured using RIA method.

Results: The level of IL-1 before the delivery was significantly higher in the group with oxytocin-induction. CRH concentration before the labour was much higher in the group with spontaneous contractions. The levels of IL-1 and CRH in both groups decreased during the labour and were lowest after the delivery. Concentration of IL-6 did not changed dependently of group and time of blood sampling. Changes in CRH in time concentration did not correlate with changes in ACTH levels. ACTH concentrations were similar in both groups, low before delivery raised during the delivery and low again after labour. Cortisol concentration in spontaneous labour was much lower before delivery in comparison with second examined group, then lowered during and after the delivery. In group with oxytocin induction, cortisol levels raised during the delivery and maintained almost the same level after the labour. The time-changes in IL-1 concentration and ACTH and cortisol levels were similar in shape in group with spontaneous delivery.

Conclusions: These results suggest that IL-6 is not involved in modulation of HPA axis in pregnancy at term. IL-1 may modulate mother's HPA axis, influencing the release of ACTH and cortisol, probably via stimulation of hypothalamic CRH.