DEFINITION Artificial stimulation of uterine contractions before spontaneous onset of labour with the purpose of accomplishing successful vaginal delivery
FETAL IUFD Fetal anomaly incompatible with life Severe IUGR Rh isoimmunisation Macrosomia INDICATIONS MATERNAL Preeclampsia, eclampsia PROM Posttermpreg Abruptio placenta Chorioamnionitis Medical conditions-DM,Heartds, Renal ds,Chr. HT etc
CONTRAINDICATIONS Severe degree CPD Major degree placenta praevia Transverse lie Previous classical CS,Myomectomy Previous>= 2 LSCS Grand multiparity Active genital herpes Hypersensitivity to inducing agent
RISKS OF INDUCTION Failure leading to CS Uterine hyperstimulation Fetal distress,death Rupture uterus Intrauterine infection,sepsis Iatrogenic delivery of preterm infant Precipitate/dysfunctional labour Inc. risk of operative vaginal delivery Inc. risk of birth trauma Inc. risk of PPH
Adverse Effects Tachysystole Criteria: >10 contractions in 20 minutes Dinoprostone Tachysystole Incidence: 33% Misoprostol Tachysystole Incidence Intravaginal gel or tablet: 31 to 49% Oral crushed form or tablet: 16 to 22%
Hyperstimulation Criteria Exaggerated uterine response (i.e. Tachysystole) Concerning Fetal Heart Rate tracing Late Decelerations Fetal Tachycardia >160 beats per minute DinoprostoneHyperstimulationIncidence: 17% MisoprostolHyperstimulationIncidence Intravaginal gel or tablet: 8% Oral crushed form or tablet: 1 to 2% Uterine Rupture in VBAC Risk: 2.5% in Trial of Labor after Cesarean
PREREQUISITES Establish indication clearly Informed consent Conformation of gestational age Assessment of fetal size & presentation Pelvic assessment Cervical assessment (BISHOPs score) Availability of trained personnel
CHEMICAL NONHORMONAL Herbs,evening primrose oil Homeopathic prep Enemas Castor oil HORMONAL Oxytocin Prostaglandins –PGE2,Misoprostol Relaxin Nitric oxide donors mifepristone METHODS OF INDUCTION NATURAL Breast/nipple stimulation Sexual intercourse Membrane stripping Amniotomy Acupuncture/acupressure MECHANICAL Balloon catheters Lamineria tents Synthetic osmotic dilators
Stripping of the Membranes Stripping of the membranes causes an increase in the activity of phospholipase and prostaglandin as well as causing mechanical dilation of the cervix, which releases prostaglandins. The membranes are stripped by inserting the examining finger through the internal cervical os and moving it in a circular direction to detach the inferior pole of the membranes from the lower uterine segment. [Evidence level C]
contd. Risks of this technique include infection, bleeding, accidental rupture of the membranes, and patient discomfort. The Cochrane reviewers concluded that stripping of the membranes alone does not seem to produce clinically important benefits, but when used as an adjunct does seem to be associated with a lower mean dose of oxytocin needed and an increased rate of normal vaginal deliveries. [Evidence level A, RCT]
Amniotomy. It is hypothesized that amniotomy increases the production of, or causes a release of, prostaglandins locally. Risks associated with this procedure include umbilical cord prolapse or compression, maternal or neonatal infection, FHR deceleration, bleeding from placenta previa or low-lying placenta, and possible fetal injury.
Balloon catheters The Atad Ripener Device in place with the two balloons inflated. The uterine balloon is at the internal os and the cervicovaginal balloon is at the external os.
Prostaglandins M/A :Act on the cervix to enable ripening by a number of different mechanisms. They alter the extracellular ground substance of the cervix, and PG increases the activity of collagenase in the cervix. They cause an increase in elastase, glycosaminoglycan, dermatan sulfate, and hyaluronic acid levels in the cervix. A relaxation of cervical smooth muscle facilitates dilation. prostaglandins allow for an increase in intracellular calcium levels, causing contraction of myometrial muscle..
contd. Risks associated with the use of prostaglandins include uterine hyperstimulation and maternal side effects such as nausea, vomiting, diarrhea, and fever. Currently, two prostaglandin analogs are available for the purpose of cervical ripening, dinoprostone gel (CERVIPRIME: 0.5 mg ) and dinoprostone inserts (PRIMIPROST :10 mg ).
Technique for Placement of Dinoprostone Gel Patient selection: Patient is afebrile. No active vaginal bleeding is present. Fetal heart rate tracing is reassuring. Patient gives informed consent. Bishop score is < 4. Bring gel to room temperature before application, per manufacturer's instructions.
Initiate Fetal Heart Rate and tocometry Start 15-30 minutes before gel inserted Continue monitoring for 30-120 minutes after Insertion Technique Use one syringe of gel (0.5 mg ) Introduce gel into cervix Just below level of internal os Intracervical is preferred over posterior fornix (if leaking p/v posterior Fx) Patient remains supine for 30 minutes
Dosing Repeat every 6 hours up to 3 doses in 24 hours End points Bishop Score of 8 or greater Strong uterine contractions Drug interactions Wait 6-12 hours before starting Pitocin