Abnormal Uterine Contraction

ABNORMAL UTERINE CONTRACTION

ABNORMAL UTERINE CONTRACTIONPREPARED BY:NISHA DWADEFINITION:

Any deviation of the normal pattern of uterine contractions affecting the course of labour is designated as disordered or abnormal uterine contraction.The criterion of effective uterine contraction is progressive dilatation of the cervix with descent of the presenting part withing the specified time limit.ETIOLOGY:

As the physiology of normal uterine contraction is not fully understood, the cause of its disordered action remains obscure. The following are the associated causes:

Primigravida with advancing age of mother.

Prolonged pregnancy (Post term pregnancy)

Over distension of the uterus due to twins and/or hydramnious

Contracted pelvis

Malpresentation and deflexed head

Full bladder

Injudicious administration of sedatives, analgesics and oxytocics.

Premature attempt at vaginal delivery or attempted instrumental vaginal delivery under light anaesthesia.

NORMAL UTERINE CONTRACTION:

There exists polarity in uterus i.e. when the upper segment contracts the lower segment relaxes

There are two pacemakers situated at each cornua of uterus

The intensity of contraction diminishes from top to bottom of the uterus.

The contraction wave starts at the pacemaker and propagates to the lower segment.

The duration of contraction diminishes progressively as the wave moves away from the pacemakerTYPES OF ABNORMAL UTERINE ACTION:

Hypotonic dysfunction(Uterine inertia)

Hypertonic dysfunction(Excessive contraction)Precipitate labourTonic uterine contraction and retraction(Bandls Ring)3) Inco-ordinate uterine actionSpastic lower segmentColicky uterusAsymmetry uterine contractionConstriction ringGeneralized tonic contractionCervical dystocia

NOTE:

The uterine space maker is situated at the cornua of the uterus and this generates uterine contractions. Effective uterine contraction, starts at he cornua and gradually sweep downwards over the uterus.

Primary dysfunctional labour is defined when the cervix dilates less than 1cm/hr following a normal latent phase of labour. In a primary dysfunctional labour, uterine activity instead of being governed by a single dominant space maker, is shifted to less efficient contractions due to emergence of other pacemaker foci.

HYPOTONIC UTERINE DYSFUNCTION(UTERINE INERTIA):

This is a common type of abnormal uterine contraction, which may present from the beginning of labour or may develop subsequently after a variable period of effective contractions.In uterine inertia, the pattern of the uterine contraction is normal but the cervical dilatation is slow.The intervals between contractions are long, the duration of contraction is short and the intensity is weak.

SIGNS AND SYMPTOMS:

Patient feels less pain during uterine contraction.

Palpation reveals less hardening of the uterus.

Uterine wall is easily indentable at the acme of pain.

Uterus becomes relaxed after the contraction; fetal parts are well palpable and fetal heart rate remains good.Internal examination reveals:Poor dilatation of the cervix (