OXYTOCIN It is an octapeptide synthesized in hypothalamus and stored in pituitory. Trade name:  Pitocin, Syntocinon(1 amp= 1 ml= 5 IU)

Action  Main action is on uterine myometrium  It promotes uterine muscle contraction  The action is greater on pregnant uterus as it has increased number of oxytocin receptors  Contraction of myoepithelial cells in breast cause expression of breast milk  ADH (Anti Diuretic Hormone) like effect in large doses, causes water intoxication

Indications :- Therapeutic PREGNANCY Second trimester abortion Induction of labour To facilitate cervical ripening for effective induction LABOUR Augmentation of labour Active management of third stage of labour – given after separation of placenta for promoting uterine contraction and stoppage of bleeding PUERPERIUM To minimise blood loss Control of post partum haemorrhage.

Diagnostic  Oxytocin challenge test (Contraction stress test)  Oxytocin sensitivity test

Routes of Administration:  IM  IV  BUCCAL TABLETS  NASAL SPRAY

Method of administration:  Induction of labour : For induction, units of oxytocin is added to 500ml of RL. The drip is started at a rate of 8 drops/mins and increased every 20 mts till the contractions are effective (contractions sustained for about 45 seconds and 3 contractions in 10 mts) and thereafter that drop rate is maintained. During this period continuous monitoring of fetal heart rate and contractions are done.  (4mU- 16 mU)  1 unit= 1000 mU

 Control of postpartum uterine bleeding:  10 – 20 units of oxytocin is added to 500ml IVF and run at a rate to control uterine atony or 10 units oxytocin can be given IM after delivery of placenta.  For inevitable or incomplete abortion:  10 units of OCT is added to 500ml of IVF and infused at a rate of mU/ mt.

Contraindications:  When vaginal delivery is not possible as in cephalopelvic disproportion, malpresenatation and malposition, severe degree of placentas previa, cord prolapsed  Previous caesarean section or hysterotomy  Incoordinate uterine contraction  Grand multipara  Contracted pelvis  Fetal distress and emergencies where surgical intervention is beneficial.  Hypovolemic state

Side effects:  Maternal  Hyperstimulation of uterus  Uterine rupture  Hypotension – due to vasodilation  Water intoxication – when high dose is given with large quantities of fluids – manifested as hyponatremia, convulsions and coma  Anti diuresis

Fetal  Fetal distress  Fetal hypoxia

OXYTOCIN CHALLENGE TEST (Contraction Stress Test)  To assess the fetal well being during pregnancy  Indications :  IUGR  Post maturity  Hypertensive disorders of pregnancy  Diabetes

Contraindications  Compromised fetus  Previous history of CS  Complications likely to produce preterm labour  APH

Procedure  The oxytocin infusion is started at an initial rate of 1mU/mt which is stepped up in every 20 mts until effective contractions are established. The alterations in FHR is recorded by electronic monitoring.

Interpretation  Positive : Persistant late deceleration of FHR  Negative : No late deceleration or significant variable decelaration  Suspicious : Inconsistent but definite decelerations do not persist with most uterine contractions.  Unsatisfactory : Poor quality of recording or adequate uterine contractions not achieved.

 A negative test is associated with good fetal outcome.  Where as a positive CST is associated with increased incidence of IUD, fetal distress in labour and low Apgar score

OXYTOCIN SENSITIVITY TEST  This is a useful test which helps in assessing the irritability of the uterus. Increasing uterus irritability results in labour.  Oxytocin at 0.01 unit per ml is prepared in a 10 ml syringe, and the injection administered at the end of a spontaneous contraction. The 0.01 unit is injected intravenously at minute intervals until a contraction occurs. The total dose given to this point is called the oxytocin sensitivity. If the contractions fails to start even after 4 injections, the uterus is unlikely to be responsive to induction

NURSES RESPONSIBILITY  Obtain baseline vital signs, FHR and uterine contractions.  Review laboratory tests, pelvic adequacy and maternal and fetal conditions before OCT administration.  Use an infusion pump for accurate control of infusion rate.  Monitor maternal BP, pulse and respirations and FHR every 15 mts.

 Monitor each contraction its duration, frequency and intensity as well as the status of uterus in between contractions.  Maintain I/O chart and watch for signs of fluid overload.  Record all data on a flow sheet.  Have magnesium sulphate available which may be used for oxytocin induced uterine tetany.

 Discontinue the infusion if :  Intrauterine pressure exceeds 75 mm of Hg.  Contractions lasting over 60 seconds  Contractions occurring more frequently than every 2 mts  Fetal distress