INTRODUCTIONThis study examined whether maternal plasma progesterone and corticotropin releasing hormone (CRH) concentrations can predict the likelihood of preterm labour.

MATERIALS AND METHODSMaternal plasma progesterone and CRH concentrations were examined in a total of 51 women. The subject cohort included 20 women who were followed from the beginning of the third trimester (28 to 34 weeks gestation), half of whom delivered early preterm and half of whom were not in labour and subsequently delivered at full term (n = 10 per group). In a follow-up experiment, 31 women who were admitted during labour for delivery were examined, 15 of whom delivered preterm and 16 of whom delivered at full term. Comparisons between women who delivered preterm and those who delivered at full term were made by t-tests.

RESULTSMean progesterone concentration was approximately 30% lower at 28 to 34 weeks gestation in women who delivered prematurely than in women who delivered at term (P < 0.001). Meanwhile, mean CRH concentration was 6-fold higher at 28 to 34 weeks gestation in women who experienced spontaneous preterm labour than in those who went into labour at term (P < 0.001). Preterm mothers had lower progesterone (P < 0.05) and CRH (P < 0.01) levels during active labour than full-term mothers. Progesterone levels normalised within 24 hours of delivery in preterm mothers, while CRH levels remained slightly elevated (P < 0.01).

CONCLUSIONSMaternal progesterone and CRH measurements taken early in the third trimester may be of use as biochemical markers of pregnancies at high risk of premature labour.

Adrenocorticotropic Hormone ; blood ; secretion ; Adult ; Biomarkers ; Female ; Gestational Age ; Humans ; Obstetric Labor, Premature ; blood ; diagnosis ; Pregnancy ; Progesterone ; blood ; secretion ; Prognosis ; Risk Assessment ; methods ; Singapore

The objective of this study was to investigate the effects of oxytocin infusion on corpus luteum (CL) function during early to mid-diestrus by measuring luteal size (LS) and luteal blood flow (LBF) along with plasma levels of progesterone (P4) and prostaglandin metabolites (13,14-dihydro-15-keto-prostaglandin F2alpha, PGFM). On day (D) 7 of the estrus cycle (D1 = ovulation), seven cows received 100 IU of oxytocin (OXY) or placebo (PL) following a Latin square design. LS and LBF increased in both groups over time and no differences were observed between the groups. PGFM did not differ either within the groups over time or between the groups at any time point. P4 of the OXY group was higher compared to that of the the PL group 360 min after the infusion (p = 0.01) and tended to be higher at the time points 450 min, 48 h, and 72 h (all p = 0.08). Results from this study support the hypothesis that OXY is not directly involved in the mechanism(s) governing blood flow of the CL and has no remarkable effects either on luteal size or P4 and PGFM plasma levels. Further investigation is needed to elucidate the role of OXY in CL blood flow during early and late luteal phases.
Animals ; Cattle/*physiology ; Corpus Luteum/blood supply/*drug effects/secretion/ultrasonography ; Dinoprost/analogs & derivatives/blood ; Estrous Cycle/*drug effects/physiology ; Female ; Immunoenzyme Techniques/veterinary ; Organ Size/physiology ; Oxytocin/*pharmacology ; Progesterone/blood/*secretion ; Random Allocation ; Ultrasonography, Doppler, Color/veterinary