**10. Conclusion**

Failure of progress in labor contributes to the increased frequency of caesarean section worldwide. If we are attempt to address this problem it is necessary to understand the reasons why this occurs, identify the women most likely to develop dystocia in labor and apply timely and appropriate interventions to correct inefficient uterine action when possible, thereby improving outcome for mothers and their babies. caesarean

To be able to get a correct diagnose in cases with suspect PROM, to avoid false positive tests, unnecessary intervention and to obtain a good prediction of onset of labor, in term as well as in preterm deliveries, is very appealing.

Our hope is that lactate value in AF will be a new and very useful diagnostic tool in obstetrical care.

#### **11. References**


LAC test and spontaneous onset of labor within 48 hours in late gestations, that is >34

Of the 81 women included in this study, 45 had a gestational age less than 34 weeks at the time of examination. Among these, 11 women (24%) had a lactate concentration of >4.5 mmol/l (positive LAC test), of whom 9 (82%) were in active labor within 48 hours. 'False negatives' (negative LAC test but delivered <48 hours) occurred in 0 of 34 women in this

A prediction of spontaneous onset of labor is even more valuable in preterm pregnancies, when antenatal steroids may be administered, and women may be referred to tertiary level of medical care. The publication showed that lactate determination in vaginal fluid seems promising as a tool to predict onset of labor within 48 hours even in women with suspected PPROM. A positive LAC test (>4.5 mmol/l) was more strongly associated with spontaneous

Failure of progress in labor contributes to the increased frequency of caesarean section worldwide. If we are attempt to address this problem it is necessary to understand the reasons why this occurs, identify the women most likely to develop dystocia in labor and apply timely and appropriate interventions to correct inefficient uterine action when

To be able to get a correct diagnose in cases with suspect PROM, to avoid false positive tests, unnecessary intervention and to obtain a good prediction of onset of labor, in term as well as

Our hope is that lactate value in AF will be a new and very useful diagnostic tool in

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**15** 

*Greece* 

**Oxytocin and Myometrial Contractility in Labor** 

*3Department of Obstetrics and Gynaecology, University Hospital of Heraklion, Crete,* 

Oxytocin (OT), a hormone exerting central and peripheral actions, plays an essential role in the mechanisms of parturition and lactation. It acts through its receptors, the number of which increases in the uterus towards labor, thus augmenting the uterotonic effect. Activated oxytocin receptors (OTR) by oxytocin, signal via a large number of intracellular pathways causing increased myometrial contractions by means of increased intracellular Ca+2 ion, increased myosin light chain phosphorylation and increased production of

Molecules that antagonize the action of oxytocin have been developed for use as tocolytic agents in the treatment of preterm labor. One presently available tocolytic, the oxytocin receptor antagonist atosiban, acts on both myometrial and decidual OTRs. However, research is in progress aimed at the development and clinical application of new oxytocin receptor antagonists with an enhanced pharmacological profile translating as higher affinity for the receptor as well as better bioavailability and improved safety. In this chapter we describe the function of oxytocin in labor and review the use of atosiban for the treatment of preterm labor, while also evaluating the current development of other OTR antagonists that

Oxytocin (OT) is a nine amino acid neuropeptide synthesized by the magnocellular neurons of the supraoptic and paraventricular nuclei of the hypothalamus. It is released into the circulation by exocytosis from the posterior pituitary and nerve terminals in response to various stimuli. The amino acids sequence in the OT molecule is: Cysteine-Tyrosine-Isoleukine-Glutamine-Asparagine-Cysteine-Proline-Leukine-Glycinamide, and with a sulfur bridge between the two cysteines. The structure of OT is very similar to that of the nonapeptide vasopressin, which differs from oxytocin by two amino acids. Oxytocin is also

are potential candidates as tocolytic drugs in the future.

**2. Oxytocin synthesis and function** 

**1. Introduction** 

prostaglandins.

N. Vrachnis1, F.M. Malamas2, S. Sifakis3,

*12nd Department of Obstetrics and Gynecology,* 

*21st Department of Obstetrics and Gynecology,* 

*4Health Center of Thira, Thira,* 

A. Parashaki4, Z. Iliodromiti1, D. Botsis1 and G. Creatsas1

*University of Athens Medical School, Aretaieio Hospital, Athens,* 

*University of Athens Medical School, Alexandra Hospital, Athens,* 

