Role Of Elastography Of The Cervix In Prediction Of Successful Induction Of Labour

Abstract

Induction of labour refers to the process of artificially starting labour by stimulating the uterus. The objective of induction of labour is vaginal birth without any associated perinatal/maternal morbidity and mortality. However IOL may increase chances of hyper-stimulation, fetal distress and increased caesarean section CS rates. Unfortunately a large number of women require labour induction even when their cervix is unfavourable, for medical reasons like hypertensive disorders of pregnancy, diabetes and for post maturity, FGR and oligohydramnios. Assessment of the favourability of the cervix is primarily done by the Bishop s score and transvaginal ultrasound for assessment of cervical length. We have used a new modality of elastography of the cervix. Elastography can be used to objectively measure and grade the cervical softness. Softening of the cervix usually precedes cervical ripening. newlineElastography is a non-invasive ultrasound based technique, for evaluating the elastic properties and stiffness of tissues. Elastography determines three mechanical properties namely stress, strain and deformation. Stress represents the pressure applied and stiffness is the resistance of the tissues to deformation. Strain is the resultant displacement that occurs. Gentle pressure is either applied by the operator via the ultrasound transducer, or the transducer is held still and tissue movement is caused by arterial pulsations and breathing movement. Thereafter a specialized software is used to produce a color map called elastogram . Obstetric elastography is still in its infancy and research has been done mainly on the cervix. Today obstetric elastography is primarily directed for evaluation of the cervix, for prediction of preterm labour and for predicting the success of labour induction. We have used strain elastography for pre-induction assessment the cervix. It is easier to perform after training. It is more objective as we have used the patient s own intrinsic factors like pulsations of vessels and respiratory movements.