Medications and Anesthesia
June 26, 2017
The knowledge you are developing about the labor and birth process enhances your ability to cope with labor. Relaxation tools and breathing patterns, if they are practiced regularly, are very effective in combating sensations of pain. Having confidence in your health care providers and the presence of a loving support person are probably some of the best ‘tranquilizers’ available.
The types of prophylactic techniques that are taught in this book are often adequate for pain control in many labors. You may, however, choose additional tools of medical assistance, medication, or anesthetics for your relaxation and comfort.
Your care providers do not have any routine orders for use of medication or anesthetics during your labor and delivery. In this chapter, we will discuss a variety of safe, effective medications and anesthetics. These techniques will be used only after giving consideration to your particular situation.
- your personal preferences,
- expected benefits,
- effects on your labor, and
- risks to you and your baby.
We urge you to participate in the decision-making process. It is important for you to become familiar with the benefits and risks of the methods available before your labor begins. You can then be confident in your ability to make good decisions for yourself during labor and birth.
A successful childbirth is one that you feel good about. It has nothing to do with being a good patient, having an easy birth, not taking medications, or the route your baby takes to be born. A healthy mother and baby are the first priorities of any birthing process.
The fetus will be affected to some degree by most medications that the mother receives because medications usually cross the placenta. The effect depends upon the particular drug and the dosage. Due to the immaturity of the fetus’s liver and kidneys, the newborn is unable to detoxify, metabolize, or excrete medications as rapidly as the mother. As obstetricians, we always seek to weigh the benefits against the risks to both mother and fetus.
Medications to Stimulate Labor
Prostin, Prepidil, Cytotec (prostaglandin), and Pitocin (oxytocin) are hormones produced naturally by the body that are given to induce and/or augment labor. Prostin may be given initially. Its primary action is to soften the cervix and make it more amenable to the use of Pitocin, but it may also stimulate uterine contractions. Pitocin stimulates contractions of the uterus. Prostin and Pitocin may be used to induce and/or augment labor for medical indications and also to minimize blood loss from the uterus after the placenta is expelled.
Methods of Administration: Prostin is applied to the vagina and cervix in a gel form. For labor induction or stimulation, Pitocin is given as a continuous, intravenous drip of a diluted solution. Rate of administration is carefully controlled by equipment that accurately measures rate of infusion. To control postpartum bleeding, the hormone is also given intravenously.
Risks and Disadvantages: Prostaglandin may cause strong or prolonged contractions of the uterus that could cause a tear in the wall of the uterus or distress in the baby. These risks are minimized by carefully supervising the mother and monitoring the dosage of the drug applied to the her cervix.
Pitocin can cause changes in the mother’s pulse and blood pressure. The main risk is that it can cause prolonged contractions of the uterus, resulting in rupture of the uterus or decreased oxygen to the baby. The risk is preventable by careful monitoring and supervision. Use of this medication has also been associated with an increased incidence of jaundice in the newborn.
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Sedatives or Hypnotics
Seconal and Phenobarbital, members of the barbiturate family, are given to promote rest and relaxation or sleep. They are usually administered in cases of prolonged early labor, when the mother has become exhausted. After the resting induced by these medications, the mother often enters the active phase of labor.
Method of Administration: These drugs may be given by mouth or by intramuscular injection.
Risks and Disadvantages: Barbiturates may cause the mother to feel drowsy or disoriented. If the drug is given repeatedly, it may accumulate in fetal tissues, causing respiratory depression and decreased responsiveness in the newborn. For this reason, the drug is not administered during the active phase of labor.
Reglan, Phenergan, and Droperidol are the most common medications used to prevent nausea. They may be administered orally or by intramuscular injection, and they are usually given in the early or active phases of the first stage of labor to reduce nausea and vomiting. They also tend to relieve tension and anxiety and may make the effects of pain medication more potent.
Risks and Disadvantages: These medications may cause drowsiness, dryness of the mouth, or changes in the blood pressure and/or heart rate of the mother. The medications seem to have little effect on the baby, although drowsiness and decreased responsiveness are theoretical risks.
The pain-relieving drugs Demerol and Stadol (analgesics) reduce the mother’s perception of pain without causing her to lose consciousness. They also promote relaxation between contractions and help the laboring mother feel more comfortable and in control. These drugs are most frequently used during the active phases of labor and may be given either by intravenous and intramuscular injection.
Risks and Disadvantages: The mother may experience dizziness and nausea. If used too early in labor, they may slow contractions. If considerable amounts are present in the newborn at birth, they may cause depression of the infant’s respirations. This can be overcome by use of specific narcotic-antagonist drugs.
Local and Regional Anesthetics
These techniques involve the use of local anesthetic drugs similar to Novocain. These agents act by altering the ability of nerves to carry messages to the brain. Their effects are usually localized to the area where they are injected or to the distribution of the nerve being blocked. The area served by the blocked nerve does not perceive pain, although the sensations of touch and pressure persist.
This technique involves the injection of a local anesthetic agent at the top of the vagina around the cervix. It is used during the active and transitional phases of the first stage of labor and provides excellent pain relief while the cervix is dilating. The mother will be aware that the uterus is contracting, but she will remain comfortable. The obstetrician or midwife administers the block. The onset of action is usually within five minutes, and the effect usually lasts for one to two hours. The block may be repeated several times if needed.
Risks and Disadvantages: If the block is administered before reaching the active phase of labor, it may cause the labor to slow down or stop. This is easily corrected by stimulating the contractions with Pitocin or by simply allowing the effects to wear off. In about 5% of cases, there may be a slowing of the baby’s heart rate that lasts for 15–20 minutes following the block.
The method should not be used if there are signs that the baby is experiencing distress.
Although very rare, fetal deaths have been reported when the medication is accidentally injected directly into the fetus.
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This method involves the injection of a local anesthetic agent on both sides of the vagina so that the perineum (area between the vagina and rectum) becomes numb. It provides excellent anesthesia for performing an episiotomy incision or for repairing lacerations following birth. It may also decrease the pressure discomfort that occurs as the baby’s head moves down the birth canal. Its effects usually last 30–90 minutes depending on the agent used.
Risks: Risks are minimal. It may decrease the mother’s urge to push during the second stage. Bleeding at the injection site is reported very rarely.
Local Infiltration of the Perineum
A local anesthetic agent may be injected directly into the tissues of the perineum, where an episiotomy incision is to be made, or where lacerations need to be repaired. This technique is safe and effective, but it does not provide as much relief from discomfort as a pudendal block.
Risks and Disadvantages: There may be increased swelling of the perineum following delivery.
Effects on the fetus are minimal.
Epidural anesthesia is an extremely versatile technique performed by a specialist in anesthesiology. The method may be used in the first and second stages of labor as well as during a forceps delivery or cesarean birth, thus allowing the mother to be awake for the procedure.
A small, plastic tubing is placed between the vertebrae into the space outside the sac containing the spinal cord. The anesthetic drugs bathe the nerves as they leave the spinal cord to go to the body. The anesthetic medication may be dripped in continuously, or it may be given repeatedly at intervals.
Dosage may vary to give different effects. During labor, a small dose can be injected so there is a band of anesthesia around the abdomen to relieve the discomfort of dilation of the cervix. For the second stage of labor and for cesarean birth, a larger dose can be administered so that the mother is numb from the rib cage down to the toes.
Risks and Disadvantages: If administered too soon, it may cause a slowing of contractions. Occasionally, there may be a drop in the mother’s blood pressure, which causes a decreased supply of oxygen to the baby. The onset of action from the time of the injection to good anesthetic effect is usually 1–20 minutes. Another drawback of the technique is that it may cause a weakening of the abdominal muscles and decrease the mother’s ability to push down, making the necessity of a forceps delivery more likely.
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This technique involves the placement of a small caliber needle between the vertebrae into the sac of fluid that surrounds the spinal cord. It provides anesthesia from the waist to the toes. It is most commonly used for cesarean birth or for vaginal forceps delivery and allows the mother to be awake during the procedure.
Risks and Disadvantages: This method produces a sudden drop in the mother’s blood pressure, which decreases oxygen to the baby. Five to ten percent of mothers who have had spinal anesthesia will experience headaches for several days. This is fairly easy to correct by administration of fluid and pain medication or by placing a blood patch in the epidural space. Long-term numbness and paralysis are not side effects of modern local anesthetic drugs used for spinal anesthesia.
Medications given intravenously, or gases breathed through a mask, may be given by an anesthesiologist to render the mother completely unconscious. This technique may be used for cesarean birth or for complicated vaginal deliveries.
It is often the fastest way to accomplish the desired method of delivery. It may be used if the baby is in distress.
The drugs that are used do cross the placenta and will put the baby to sleep if enough time elapses between onset of anesthesia and actual delivery. Some people consider the fact that the mother is unconscious during the delivery an advantage, but most people consider it a disadvantage.
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Transcutaneous Electrical Nerve Stimulation (TENS)
TENS is relatively new as a pain reliever during labor. A very small electric current is used to override the nerve in the spinal column during contractions. This is accomplished by a small battery-powered stimulator with wires leading to self-adhesive electrodes placed on the lower abdomen and lower back.
The box contains a rheostat-type of switch, which can gradually increase or decrease the amount of current the device produces.
Most people liken the sensation to the prickly feeling of a shower massager. TENS provides the following benefits:
- Decreased discomfort during contractions
- The laboring woman can control the method on her own
- There is no sedation of either the mother or the baby
To date, no serious problems have been seen with the TENS unit. If you are interested in this method, you should notify your physician or nurse midwife so that a requisition can be made for the Physical Therapy Department at the hospital to teach you how to use the device.
|Type||Where Given||Area Affected||Maybe Given||Time to Take Effect||Duration of Effect||Comments|
|Paracervical block||Into nerve on both sides of cervix and vagina||Cervix and Uterus||4-9 centimeters||3-5 minutes||1-2 hours||Given by obstetrician: may be repeated as needed with 90% success rate. May slow labor if given too early. Additional medication, usually local or pudendal, is required for episiotomy and/or repair.|
|Epidural block||Lumbar spine region; given in side-lying or sitting position||1st stage of labor: waist to knees; 2nd stage of labor: ribcage to toes||After 5 centimeters||10-20 minutes||1 1/2 hours||Continuous dose through catheter placed in epidural space; given by anesthesiologist. May cause drop in maternal heart rate. Diminishes urge to push and bearing-down reflex and impairs normal rotation and descent of baby, increasing need to forceps. May be used to cesarean birth.|
|Spinal block||Usually between 3rd and 4th lumbar vertebrae; given in side-lying position||From breast level down||2nd stage||3-5 minutes||1 1/2 – 2 hours||Often used for cesarean birth; given by anesthesiologist. Possible “spinal headache” afterward. Possible drop in maternal blood pressure. May cause difficulty with urination later.|
|Pudendal block||Into pudendal via vagina||Vagina and perineum||2nd stage||2-3 minutes||30-90 minutes||Given by obstetrician–not 100% effective. Fetal risks unknown; excessive amounts may cause fetal depression. Used for discomfort during delivery, when forceps are necessary, or for episiotomy and/or repair. May inhibit bearing=down reflex by relaxing muscle tone or perineum|
|Local||Perineum||Perineum||2nd or 3rd stage||5 minutes||20 minutes||Given by obstetrician for episiotomy and/or repair.|