Proceedings of The Physiological Society

University of Edinburgh (2007) Proc Physiol Soc 6, C6

Oral Communications

The CRH concentration before parturition and spontaneous contractile activity in twin pregnancies.

T. Ochedalski1, A. Lachowicz2

1. Department of Perinatology, Medical University of Lodz, Lodz, Poland. 2. Department of Comparative Endocrinology, Medical University of Lodz, Lodz, Poland.

According to the recent research regular contractile activity is result of three factors: degree of mechanical stretching of uterus, maturity of the fetus, and proper function of hormonal ability of placenta and maternal hypothalamo-pituitary-adrenal axis (HPA). The concentration of corticoliberin (CRH), the main hormone of HPA axis rapidly increase after 38 week of physiological pregnancy, and this increase may induce spontaneous labor. In case of twin pregnancies the spontaneous contractile activity occurs earlier in comparison to singletons, however the age of pregnancy and maturity of the fetuses are not advanced enough. It seems possible that bigger degree of stretching of the uterus is main factor triggering the spontaneous labor. The aim of this study was investigation the changes of CRH and other hormones of HPA axis (ACTH, DHEA and cortisol) and influence of these hormones on beginning of spontaneous contractility. Maternal levels of CRH, ACTH, DHEA and cortisol were determined 48 hours before and after parturition in the blood obtained from 6 women in twin pregnancies, in 36/37 week of pregnancy. Three of them delivered babies in spontaneous way, three underwent elective cesarean section. The concentration of CRH was higher in women delivered spontaneously, similar to the singletons. The levels of ACTH, DHEA and cortisol before labor were higher then in singletons. After the parturition only ACTH concentration lowered in comparison to the values observed before delivery. The obtained results suggest that CRH together with stretching the uterus may play the important role in initiation of parturition. This hormone is consider to be the specific biological clock timing the moment of beginning of spontaneous contractile activity of the uterus, nevertheless the age of pregnancy. Key words: spontaneous contractile activity, spontaneous labor, elective cesarean section, corticotropin releasing hormone, adrenocorticotropin, cortisol. Reference 1 : Challis JRG, Characteristic of parturition. In: Creasy RK, Resnik R (eds) Maternal-Fetal Medicine: Principles and Practice. W.B. Saunders Co., Philadelfia, 1998, pp 484-497.Reference 2 : Lockwood C J. The initiation of parturition at term. Obstet Gynecol Clin N Am 2004;31:935-947.Reference 3 : Norman RJ, Deppe WM, Coutis PC, Marivate M, Joubert SM. Twin pregnancy as a model for studies in fetal cortisol concentration in labour: relation to prostaglandins, prolactin and ACTH. Br J Obstet Gyneacol 1983;90:1033-9.Reference 4 : Warren WB, Goland RS, Wardlaw SL, Stack RI, Fox HE, Conwell IM. Elevated maternal plasma corticotropin hormone levels in twin gestation. J Perinat Med. 1990;18:39-44.Reference 5 : Ochedalski T, Zylinska K, Laudanski T, et al.: Corticotropin releasing hormone and adrenocorticotropin levels in maternal and fetal blood during spontaneous and oxytocin-inducted labour. Eur. J of Endocrinology 2001;144:1-6.

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