Management of Labur - Normal and Abnormal; Including Peuperium

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Pelvic inlet:

Anteriorly -by pubic symphysis
Laterally -by upper margin of pubic bone, iliopectineal line, ala of sacrum
Posteriorly- sacral promontory.

Pelvic midcavity:

Anteriorly- middle of pubic symphysis
Laterally- pubic bone, obturator fascia and inner aspect of ischial bone and ischial spine.
Posteriorly- junction of S2 & S3.

Pelvic outlet:

Anterioly- lower margin of pubic symphysis,
Laterally- descending ramus of pubic bone, ischial tuberosity and sacrotuberous lig.
Posterioly- last piece of sacrum

Pelvic dimensions

Inlet: transversely=13.5cm; AP: 11cm
Midcavity: transverse = 12cm; AP = 12cm
Outlet: transverse = 11cm AP = 13.5cm

Sutures are lines between the bony plates. Sutures lines on the vault are soft, unossified membranes.

Bones of the vault- parietal bones, occipital bones, frontal bone and temporal bones.

During labor the vault bones may overlap= moulding.

Fontanelles- junctions of sutures. E.g.

Anterior fontanelle – diamond shape (at junction of sagittal, frontal and coronal sutures)
Posterior fontanelle- triangular (at junction of the sagittal suture and lambdoidal sutures)

Diameters of fetal skull

Well flex fetal head (vertex presentation)-

Longitudinal diameter is 9.5cm measured from suboccipito-bregmatic diameter
With extension of fetal head the longitudinal diameter increases.
The greatest longitudinal diameter is mento-vertical (from mentum to vertex: face presn) = 13cm, too large to pass thru the pelvis

The mechanism responsible for initiation of labor is unknown.

Some contributory factors include:

Hormonal

Prior to labor, reduction in progesterone receptors
Increase in concentration of estrogen relative to progesterone

Prostaglandin and oxytocin release

Maternal corticotrophin releasing hormone (CRH) increases in concentration and potentiate the action of oxytocin and prostaglandins on myometrial contractility. Fetal cortisol- converts progesterone to estrogen.

Myometrial factor

Prostaglandin and oxytocin increase myometrial intracellular free calcium ions which results in increase in formation of contractile actin-phosphorylated myosin

These are series of events (changes in position and attitude) that occur during the passage of the fetus through the birth canal.

Mechanism of labor for vertex presentation and gynecoid pelvis

ED-FIEREDD

Engagement
Descent
Flexion
Internal rotation
Extension
Restitution
External rotation
Delivery of the shoulders
Delivery of the fetal body

Position and mechanism of delivery of the baby
Source: Geeky Medics

Symptoms & Signs of onset of labor:

Regular abdominal pain
Backache
Show
Liquor drainage

In latent phase- palpable uterine contractions minimum of 1 in 10min, cervical dilatation and effacement.

1ST STAGE

This is the stage which represent dilatation of the cervical os from 0 cm to full cervical dilatation of 10 cm in a parturient at term.

It is composed of two phases

Latent phase:

Woman at term with labor pains
Uterine contraction frequency of at least once every 10 minutes interval
Sterile vaginal exam reveals a cervical dilatation <4cm
Normal latent phase lasts a maximum duration of 8 hours, usually shorter in multiparous women.
Latent phase is prolonged if it extends beyond 8 hours up to a maximum of 24 hours without the woman developing features of active phase.
If after 24 hours, the woman has still not developed the features of active phase of labor but still maintains the features of latent phase, then the correct diagnosis is false labor.

Active phase:

Cervical dilatation =/> 4cm to 10 cm
At this stage, the cervical os characteristically dilates at 1 cm per hour
Conventionally, a period of 12 hours is the maximum duration, shorter in multiparous women.

2ND STAGE

This is the stage of labor from full cervical os dilatation of 10 cm till the baby is delivered.

Can also be divided into two phases

The propulsive/passive phase- starts from full dilatation up to the descent of the presenting part to the pelvic floor. Often manifested by an irresistible urge to push by the mother.
The expulsive/active phase- this phase is enhanced by voluntary pushing effort of the woman and may be shortened by an episiotomy.

Both phases last a duration of one hour each. Hence, a normal active second stage should not last more than 2 hour in a nulliparous woman and 1 hour in women who delivered vaginally before.

Use of epidural anesthesia will influence the length and management of the second stage of labor. A passive second stage of 1 or 2 hours is usually recommended to allow the head to rotate and descend prior to active pushing.

3RD STAGE

This is the time from delivery of the fetus or fetuses until complete delivery of the placenta (e) and membranes.

Occurs 1—10 minutes after the birth of the baby

A third stage lasting more than 30 minutes is defined as abnormal and the placenta is said to be retained.

The drastic decrease in the volume of the uterine cavity after the expulsion of the fetus has the effect of shearing off the placenta from the decidual attachment.

This separation is reinforced by contractions and retractions of the uterine muscles by the mother during bearing down.

Signs of placenta separation are

Apparent lengthening of the umbilical cord
A small gush of blood from the placental bed
Rise of uterine fundus to above the umbilicus
Uterus assuming a more globular shape and become hardened

An abnormal third stage will be marked by

Poor uterine contractions
Poor or no placental separation and expulsion
Significant blood loss exceeding 500 ml.

Normal labor: when uterine contractions begin spontaneously at term and the fetus & placenta are delivered per vaginam with 12 hours maximum duration irrespective of whether or not some interventions (like oxytocin augmentation) were required to assist or facilitate the process.

A normal labor is a retrospective diagnosis

At presentation/admission

Biodata

Presenting complaint / History of labor

Onset, frequency, duration and perception of strength of uterine contraction

Abdominal pain, back pain, show

Whether membranes have ruptured and, if so, color and amount of amniotic fluid lost.

Presence of abnormal vaginal discharge or bleeding

Recent activity of the fetus (Fetal movement)

Medical or obstetric

History of Index pregnancy

Past obstetric history

Previous births and size of previous babies
Obstetric issues of note
Etc.

Past medical history

Medical issues of note e.g. diabetes, hypertension, etc.

Physical examination

General examination- pallor, jaundice, PR, BP

Abdominal examination

Obstetric examination

Symphysio-fundal height
Lie
Presentation
Position
Engagement
Fetal heart sound

Vaginal examination

Cervix – consistency, position, dilatation, effacement, membrane intact, liquor color, station of the presenting part
Position of the presenting part
Caput
Moulding
Adequacy of the pelvis

Basic investigation:

PCV
Urinalysis
+/- Grouping & crossmatching for high risk cases
Lentiviral screening test for un-screened patient

Intrapartum monitoring

Chart on Partograph
FHR- ½ hourly
Uterine contraction- ½ hourly
Pulse rate- hourly
BP - hourly in normotensive patient
Vaginal examination- 4 hourly
Temperature- 4 hourly
Urinalysis- 4 hourly /or whenever she passes urine

Progress of labor

Assessment of progress of labor

Uterine contraction
Descent of the presenting part
Cervical dilatation

Primary dysfunctional labor

Defined as a labor in which the active phase progresses at a rate of less than 1cm / hr before a normal active phase slope has been established.
It is usually due to inefficient uterine contraction
Treatment – majority will respond to oxytocin

Secondary arrest

Occurs when cervical dilatation ceases after a normal portion of active phase dilatation.
Causes: inefficient uterine contraction, malpresentation/malposition, CPD
Treatment- depends on the etiology- oxytocin, C/S, etc.

First stage of labor

Latent phase

The pregnant woman will often present with the claim they are in labor.

The woman is admitted and history is taken.

A detailed clinical assessment is done, including a vaginal examination.

The Bishop Score is assessed at the vaginal examination and recorded.

The woman is closely observed till features of active phase labor occur.

Monitor and record fetomaternal vital signs.

This stage does not require any intervention in the absence of any other concomitant obstetric problem. Common possible problems that may require intervention includes

Pre-eclampsia/eclampsia
Prolonged pregnancy
Medical problems such as anemia, diabetes mellitus, renal disease, etc.

Interventions will also be justified if complications develop. Complications such as

Fetal distress
Hypertension
Rupture of fetal membrane

Repeat vaginal examination and begin active phase management if features of active phase such as cervical os dilatation of 4 cm or greater is found at vaginal examination.

If there are still no active phase features after vaginal examination done at 8 hour from the first examination, the diagnosis is now prolonged latent phase.

If after 24 hours from the first vaginal examination, a repat vaginal examination still confirms persistent latent phase features, the diagnosis is now revised as false labor.

Active phase

Inform the woman that she is in the active phase and assure her of companionship and support.

Continue to observe the progress of labor. This involves regular assessment and recording of the maternal and fetal conditions, and also the current state of labor.

Maternal

Blood pressure
Pulse
Temperature
Urinalysis

Fetal

Fetal heart rate
State of membranes
Caput
Moulding

Labor

Contractions
Cervical os dilatation
Head descent

These findings are recorded on a partograph.

Adequate pain relief

Adequate hydration as required to prevent ketosis

Therapeutic interventions used such as IV fluids, oxytocin, pain relief are also recorded.

Continue to monitor fetal wellbeing to easily pick out changes in fetal status. The intensity of contractions in the active phase at its peak can reduce placental blood flow and cause hypoxia. This is easily tolerated in a normal fetus but an already compromised fetus might become distressed. These changes might cause distress in all fetuses (normal or compromised) when the active phase last longer than 12 hours. The evidences of fetal distress include

Meconium in the liquor
Excessive fetal movement that can be confirmed with an electronic monitor.
Fetal heart rate anomalies.

Second stage

Often the beginning of the second stage is suspected when the woman expresses the irresistible urge to push.

A vaginal examination can be done to confirm full cervical dilatation.

The woman will get an expulsive reflex with each contraction, and will generally take a deep breath, hold it, and strain down (the Valsalva manoeuvre).

Use of regional analgesia (epidural or spinal) may interfere with the normal urge to push, and the second stage is more often diagnosed on a routine scheduled vaginal examination.

Women should be discouraged from lying supine, or semi-supine, and should adopt any other position that they find comfortable. Lying in the left lateral position, squatting and ‘all fours’ are particularly effective options.

If at full cervical os dilatation, there is poor head descent, no urge to push and CPD has been excluded, oxytocin can be used to augment labor.

Maternal and fetal surveillance intensifies in the second stage, as described previously. The development of fetal acidemia may accelerate, and maternal exhaustion and ketosis increase in line with the duration of active pushing. Fetal assessment options include

Inspection of amniotic fluid- fresh meconium staining, absence of fluid, and heavy blood-stained fluid or bleeding are markers of potential fetal compromise.
Intermittent auscultation of the fetal heart using a Pinard stethoscope or a hand-held Doppler ultrasound.
Continuous external electronic fetal monitoring (EFM) using CTG.
Continuous internal electronic fetal monitoring using a fetal scalp electrode (FSE) and CTG.
Fetal scalp blood sampling (FBS).

An episiotomy can be performed to hasten delivery if there is suspected fetal compromise (e.g. fetal bradycardia). It will only accelerate the birth if the head has passed through the pelvic floor, so should not be performed too early. It is performed during most instrumental births (ventouse or forceps). Effective analgesia is required, and this will usually be with infiltration of local anesthetic if the woman does not have an epidural.

Third stage

The third stage is the interval between delivery of the baby and the complete expulsion of the placenta and membranes.

Management of the third stage can be described as ‘active’ or ‘physiological/passive’.

Active management

Consists primarily of

Intramuscular injection of 10 IU oxytocin, given as the anterior shoulder of the baby is delivered, or immediately after delivery of the baby.
Early clamping and cutting of the umbilical cord.
Controlled cord traction

Evidence shows that it reduces the incidence of postpartum hemorrhage (PPH).

Controlled cord traction

When the signs of placental separation are recognized, controlled cord traction is used to expedite delivery of the placenta.

When a contraction is felt, the left hand should be moved suprapubically and the fundus elevated with the palm facing towards the mother (countertraction). At the same time, the right hand should grasp the cord and exert steady traction so that the placenta separates and is delivered gently, care being taken to peel off all the membranes, usually with a twisting motion.

Uterine inversion is a rare complication, which may occur if the uterus is not adequately controlled with the left hand and excessive traction is exerted on the cord in the absence of complete separation and a uterine contraction.

Physiological management

Physiological management of the third stage is where the placenta is delivered by maternal effort and no uterotonic drugs are given to assist this process. Separation is awaited and placenta and membranes allowed to deliver spontaneously with the aid of gravity or with nipple stimulation.

This method is easily complicated by primary post-partum hemorrhage (PPH).

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Management of Labor - Normal and Abnormal; Including Peuperium