Introduction

Fetal Development

The Danger Signs of Pregnancy

The Pregnant Patient's

Sexual Intimacy

Weight Gain

Communication Skills

Labor Coping Strategies

Birth Options and Preferences

What to Take to the Hospital

Labor

Addendum

Labor Continued

Induction and Augmentation of Labor

Definitions

Induction of Labor The induction of labor is the arti-ficial initiation of labor through eithermechanical means or, more commonly, the use of medication.                                     

Augmentation of Labor The augmentation of labor is the artificial stimulation of an already established labor through either mechanical means or, more commonly, the use of medication.

Reasons for Induction or Augmentation of Labor

Types of Induction and Augmentation

“Stripping the Membranes”
The physician inserts a finger through the soft, dilatable cervix at term and pushes the fetal membranes (amniotic sac) off the uterine wall in and around the cervix.  This procedure may cause a release of prostaglandins (hormones which influence labor).  This is known as the “Furgeson Reflex”.

This method of induction may be appropriately used in a woman who is at term and who has an inducible cervix.

Amniotomy or Artificial Rupture of the Membranes
An amnihook (sterile, plastic instrument that looks somewhat like an elongated crochet hook) is inserted with the physician’s fingers into the vagina.  A tear is made in the amniotic membranes with the amnihook.  The fetal head must be engaged and, usually, the cervix should already be 3-4 cm. dilated.

This method is not commonly used for induction of labor although it is often used in the augmentation of labor.

Pitocin Drip (“Pit Drip”)
A mainline IV of plain intravenous solution is established.  A secondary IV intravenous solution mixed with natural oxytocin (Pitocin) or synthetic oxytocin (Syntocinon) is piggyback onto the mainline IV.  The tubing of the secondary IV is placed through an infusion pump.  By way of the infusion pump the quantity of oxytocin (Pitocin) allowed to enter the woman’s bloodstream is regulated.  Incrementally over time the infusion rate is increased until labor contractions are typically 2 ½-4 minutes apart, last at least 50-60 seconds, and result in intrauterine pressures of 50-75 mm Hg.

During a Pitocin-induced or augmented labor, the woman must be attached to the electronic fetal monitor continuously in order to assess the frequency and duration of contractions.  Also assessed is fetal well-being in response to a Pitocin-regulated labor.

An induced or augmented labor is different than a spontaneous labor.  The latent phase of labor is reduced or eliminated.  The mother does not go through a slow, progressive buildup of contractions.  Once Piticon is administered and takes effect, contractions of good strength, length and frequency occur.  The opportunity to accustom oneself gradually to the contractions of active labor may be by-passed.  Consequently, labor may seem more difficult.  These strong contractions may or may not produce a change in the cervix right away.

This method is commonly used to induce and/or augment labors.

Electronic Fetal Monitoring

Electronic fetal monitors were originally developed to assist the obstetrical staff in evaluating how the complications of high risk labor (such as PIH-pregnancy induced hypertension, bleeding, early rupture of membranes without ensuing labor, etc.) impacted on the fetus’ tolerance of labor.  EFMs are now commonly used to assess the fetus in virtually all labors.  Prior to the introduction of electronic fetal monitors, fetal monitors, fetal monitoring was accomplished by a nurse or physician listening to the fetal heart rate with a fetoscope or a Doppler while feeling the intensity of the contractions with his or her hands.

The main goal of any form of fetal monitoring is to assess fetal well-being in response to the stress of labor.  The advantage of assessing fetal well-being is the ability to detect and prevent problems in their earliest stages when appropriate interventions can be the most advantageous for the mother and baby.

Continuous electronic fetal monitoring is used routinely by most doctors and hospitals for their laboring patients.  Some physicians, however, may choose to allow intermittent fetal monitoring throughout labor with select patients.  This provides more freedom of movement for the woman in labor.

There are two methods of acquiring information via the electronic fetal monitoring: External Monitoring and Internal Monitoring.

External Fetal Monitoring

Tocodynamometer (Toco)
A belt is placed around the woman’s abdomen to which is attached a pressure sensitive device “Toco”- that detects uterine contractions.

Indications For Use:

• Patient in labor.
• Patient in preterm labor.
• With (fetal) stress testing: NST; OCT; CST.
• To access the uterine muscle response to Pitocin induction or augmentation.

Advantages/Benefits:

• Able to assess the frequency and duration of contractions.
• Non-invasive.
• Visually indicated onset of uterine contractions so laboring woman may begin relaxation and breathing techniques.

Disadvantages/Risks:

• Unable to accurately assess the intensity of uterine contractions.
• May require readjustments due to the woman’s movements, the belt slipping, etc.
• Restricts the woman’s movements and ability to use effleurage.
• May be less accurate than internal monitoring device.

Doppler Ultrasound
A belt is placed around the woman’s abdomen to which is attached an ultrasound device-a Doppler which measures the fetal heart rate.

Indications For Use:

• Patient in labor.
• Patient in preterm labor.
• With (fetal) stress testing: NST; OCT; CST.
• To assess well-being of the fetus with Pitocin induction or augmentation.

Advantages/Benefits:

• Able to assess fetal well-being by observing fetal heart rate in relation to uterine contractions.
• Non-invasive.

Disadvantages/Risks:

• May be less accurate than internal monitoring device.
• May require readjustments due to the woman’s movements, the belt slipping, or baby’s movements.

Telemetry Unit
A small hand-held radio-sized unit worn by a strap around the woman’s neck and              connected to two external abdominal belts with a toco and doppler attached.

Indications For Use:

• Same as for Tocodynamometer and Doppler Ultrasound

Advantages/Benefits:

• Same as for Tocodynamometer and Doppler Ultrasound
• Freedom of movement for the woman during labor as she may walk about and move freely within a specified area from the remote station receiving the signal from the telemetry unit.

Disadvantages/Risks:

• Same as for Tocodynamometer and Doppler Ultrasound

Internal Fetal Monitoring

Intrauterine Pressure Catheter (IUPC)
A pressure-sensitive catheter which is passed through the vagina into the uterus.  When contractions occur, the changes in intrauterine pressure is translated via the changes in the sterile water column in one type of IUPC, or in the microchip in the head of another type of IUPC.  This information is then measured and recorded.

Indications For Use:

• High risk labors requiring accurate data.

Advantages/Benefits:

• Assesses frequency, duration and intensity of uterine contractions.
• Visually indicates onset of uterine contractions so the laboring woman  may begin relaxation and breathing techniques.

Disadvantages/Risks:

• Invasive
• Requires rupture of membranes
• Restricts movement because the catheter may be displaced by the woman’s movements. 
• Cannot get up to use bathroom because gravity causes the catheter to fall out of position.
• Possibility (rare) of introducing infection.

Fetal Scalp Electrode
An electrode is passed through the vagina and is attached by a thin spiral wire to the fetal scalp skin.  The electrode detects the electrical signal of the fetal heart rate and sends it to the EFM where it is recorded.

Indications For Use:

• High risk labors requiring accurate data.
• When the external tracing is difficult to interpret.
• Convenience.

Advantages/Benefits:

• Able to assess fetal well-being by observing fetal rate in relation to the uterine contractions.
• Signal usually unaffected by the woman’s movements or the baby’s movements.
• More accurate tracing of fetal heart rate.

Disadvantages/Risks:

• Invasive.
• Requires rupture of membranes.
• Possibility of introducing infection.
• Possibility of attaching scalp electrode to inappropriate site.

Next: Labor Continued