Kingdom of Saudi ArabiaMinistry of Higher Education King Faisal University College of Medicine Normal Labor By/ Fahad AlHulaibi Mansour Al Omair Ahmed Al Awwad Abdulaziz Al Barrak
ObjectivesBy end of this Tutorial, you will be able to : Diagnose The Onset Of Labor . Define Stages Of Labor. Understand The Mechanism Of Normal Labor. Monitoring The Mother & The Fetus During Labor. Understand Management Of Normal Labor.
30 months - 24 months = 6 months Or 24 weeks“age of viability”
Definition Labor:Is the process whereby the product of conception are expelled from uterian cavity after 24th week of gestation.
Definition Premature labour:labour occurring before the commencement of the 37th week of gestation Prolonged labour:labour lasting in excess of: 24 hours in a primigravida&16 hours in a multigravida.
Onset of labour The onset of labour is defined as the time of onset of regular, painful uterine contractions, which produce progressive effacement and dilatation of the cervix. false labour: where the onset of painful contractions is not associated with progressive dilatation of the cervix.
The clinical signs of the onset of labour include:1. The onset of regular, painful contractions that produce progressive cervical dilatation.2. The exhibition of a vaginal show - the passage of blood stained mucus.3. Rupture of the fetal membranes - may occur at the time of onset of contractions or it may be delayed until the delivery of the fetus.
Stages of labour The First Stage • onset of labour start • Cervix reached full end dilatation
The Second Stage • Cervix reached full start dilatation • expulsion of the fetus end
The Third Stage “Placenta Stage “ • delivery of the child. start • expulsion of placenta. end
The classic signs of placental separation :1. show of bright blood.2. apparent lengthening of the umbilical cord3. elevation of the uterine fundus within the abdominal cavity .
Mechanism of Normal labour Engagement of the head normally occurs before the onset of labour in the primigravid woman but may not occur until labour is well established in a multipara. Only 2/5th of the head will be palpable per abdomen Zero station on vaginal examination
Mechanism of labour 1. Descent of the head provides a measure of the progress of labourDescent occurs throughoutlabour
2. Flexion of the head occurs as it descends and meets the pelvic floor, bringing the chin into contact with the fetal thorax. Flexion producesa smaller diameter of presentation(suboccipitobregmatic diameter)
3. Internal rotation:The head rotates as it reaches pelvic floor and the occiput normally rotates anteriorly from the lateral position towards the pubic symphysis
4. Extension: The acutely flexed head descends to distend the pelvic floor and the vulva, and the base of the occiput comes into contact with the inferior rami of the pubis. The head now extends until it is delivered. Maximal distension of the perineum and introitus accompanies the final expulsion of the head, a process that is known as crowning.
5. Restitution: Following delivery of the head, it rotates back to be in line with its normal relationship to the fetal shoulders 6. External rotation: When the shoulders reach the pelvic floor, they rotate into the anteroposterior diameter of the pelvis. This is accompanied by rotation of the fetal head so that the face looks laterally at the maternal thigh.
7. Delivery of the shoulders: The anterior shoulder is delivered first by traction posteriorly on the fetal head so that the shoulder emerges under the pubic arch.The posterior shoulder isdelivered by lifting the headanteriorly over the perineum.This is followed by rapiddelivery of the remainder ofthe trunk and the lower limbs
Auscultation The heart rate should be recorded every 15 minutes in the first stage and after each contraction in the second stage, using a Pinard fetal stethoscope Cardiotocography is not required when the labour is classified as low risk. However, there are specific indications for electronic fetal monitoring.
Indications for continuous electronicfetal monitoring Maternal Previous caesarian section Pre-eclampsia Post-term pregnancy Prolonged rupture of the membranes Induced labour Diabetes Antepartum haemorrhage Other maternal medical diseases
Cardiotocogram Components: Base line fetal heart rate Base line variability Accelerations Decelerations Uterine Contractions
Fetal Heart Rate Normal Range 110-160 beats/min More than 160 is tachycardia Less than 110 is bradycardia
Baseline Variability Normal Range 6-25 Increased (more than 25) Early Hypoxia Prolonged pregnancy Decreased (less than 6) Latehypoxia Sleep Vibro-acoustic stimulation
Accelerations Transient increase in heart rate more than or equal to 15 beats for more 15 seconds. Assuring of good fetal health if present
Decelerations Transient decrease in heart rate more than or equal to 15 beats for more 15 seconds. Normally not present. Types (in relation to uterine contractions) Early Late Variable
Early Decelerations They are synchronous with uterine contractions. The nadir of the deceleration occurs at the peak of the contraction and the decrease in heart rate is generally less than 40 beats/min.
Cont. These decelerations are generally due to head compression and are commonly considered to be physiological. They are a common form of deceleration seen in labour
Late Decelerations The onset of the slowing of heart rate occurs well after the contraction is established and does not return to the normal baseline until at least 20 seconds after the contraction is completed. They are indicative of fetal hypoxia.
Variable Decelerations Variable decelerations vary in timing and amplitude, hence their name. An early deceleration where the heart rate falls by more than 40 beats/min is also classified as a variable deceleration. Types: Mild:Total duration is >30 sec, or FHR >80 bpm Moderate: FHR 80-70 bpm Severe: FHR <70 bpm for more than 1 min
Cont. The commonest cause is cord compression and the changes may be considered to be pathological if the cord compression is persistent
Uterine Contractions Tocodynamometer A pressure-sensitive tocodynamometer is placed around the maternal abdomen. The tocodynamometer measures only the frequency of contractions, not their intensity or strength. Intrauterine pressure catheter (IUPC). Thismethod allows internal monitoring of contractions. IUPC measures both the frequency and strength of contractions.
Electrocardiogram The fetal electrocardiogram (ECG) can be recorded from scalp electrodes or by the placement of maternal abdominal electrodes.
Two items are important: Acidosis(T wave and QRS height) Asphyxia (PR interval and RR interval) The fetal ECG can also be used to identify the nature of fetal arrhythmias.
Scalp stimulation test The examiner rubs the fetal scalp during a digital examination. An acceleration is usually seen in the FHR tracing of the uncompromised, nonacidotic fetus. The presence of an acceleration is associated with an intact ANS and a fetal scalp blood pH greater than 7.20. If an acceleration is not obtained after scalp stimulation, fetal scalp blood can be sampled to measure the fetal pH or one can progress to immediate surgical delivery.
Fetal scalp blood sampling The fetal scalp is visualized through the dilated cervix, and blood is collected in heparinized capillary tubes The normal fetal capillary pH is 7.25 to 7.35 in the first stage of labor. A fetal scalp pH greater than or equal to 7.20 is reassurance that the fetus is not acidotic. Labor can proceed for 20 to 30 minutes. A pH of less than 7.20 may represent significant acidosis. Delivery is thus indicated by vaginal delivery, if possible, or cesarean delivery.
Others Vibroacoustic stimuli (VAS). Fetus is stimulated by noise for 1 second. The presence of fetal accelerations in response to VAS is considered reassuring. The fetus is restimulated if no accelerations occur within 10 seconds. The VAS test may be repeated up to four times. Normal fetal oxygen saturation: ranges between 35% and 75%, If the fetal oxygen saturation remains above 30% during labor, fetal metabolic acidosis is excluded.
Partogram Partogram is a graphical record of key data (maternal and fetal) during labour entered against time on a single sheet of paper.
Components Fetal Parameters: FHR Statusof membranes or Amniotic Fluid Moulding Caput
Progress of Labor: Cervical dilatation Station of head Uterine contractions: Frequency & Duration Oxytocin: Concentration /L Infusion rate Any other medicine & IV fluid
General principles of the management ofthe first stage of labour :• Observation and intervention if the labour becomesabnormal by partogram .• Pain relief during labour and emotional support forthe mother ( Narcotic agents , inhalational analgesiaand regional analgesia )• Adequate hydration throughout labour.