Which produces less affect on the baby? Epidural or I.V method?

Effect of epidural anesthetic on babies

Usually two types of medications are used to produce effective epidural analgesia; local anesthetics and opioid (narcotic) medications. Local anesthetic medications given into the epidural space can reach the baby via mother's blood circulation. However, the amount reaching the baby is too small to have an effect on the baby's heart rate, or on the general alertness of the baby after delivery. Similarly, opioids used in the epidural injections can also reach the baby. Once again, the amount of opioids reaching the baby is much smaller when compared to the amounts reaching the baby when the mother is getting systemic (I.V) opioid medications.  This is because only a fraction of amount of opioids that are used in systemic (I.V) method are used in an epidural injection. 

Occasionally, within 10 to 15 minutes of epidural injection of local anesthetic or opioid, fetal (baby) heart rate may show changes such as slowing of heart rate with or without changes in heart rate pattern (decreased beat-to-beat variability) in about 30% of pregnant women.(1,2)  This may be particularly so, it seems, in those individuals  suffering severe pain and distress prior to providing pain relief. However, these baby heart rate changes are transitory, and last only 3 to 4 minutes. As long as baby's heart rate is monitored continuously  (as is generally practiced), and corrective measures undertaken, these transitory changes should not give rise to great concern.

A side effect of epidural pain relief which sometimes occur is a drop in mother's blood pressure. This, if excessive and not treated, can affect the baby. This is not a major concern however, as the blood pressure is always measured as frequently as the situation demands after the initiation of epidural anesthesia, and corrective measures undertaken if necessary.

Tests of neonatal neurobehavior (tests performed to assess activity of newborn) after exposure to various methods of pain-free child birth have produced conflicting results. In recent years, however, the doses of local anesthetic medications and opioids used for providing child birth pain relief via epidural analgesia have gradually decreased, and there is now general consensus that within the dose range presently en vogue, and under normal circumstances, the effects of the local anesthetics on the new born baby have little or no clinical significance. 

Under some circumstances, an epidural pain relief can be beneficial for the baby as is for example in pregnant women with preeclampsia (high blood  pressure, swollen feet, etc). An epidural analgesia can improve blood flow to the baby during labor and delivery.(3) 

All medications given in the I.V to the mother cross the placenta and enter the baby's circulation. As a result of this, the baby may also show some effects. In utero, the baby's heart rate may change slightly in pattern. There is no deleterious effect known due to this change in heart rate pattern. 

A major concern of I.V medications during child birth is their depressing affect on the newborn baby. The affect of I.V medications on the newborn baby is dependent on the type and dose of medication,  as well as timing of medication prior to delivery. If the baby has adequate time to break down the medication before being delivered, only a minimal effect may be seen. The baby may be normal or may be slightly sleepy. There may be a transient change in neurobehavioral scores (tests performed to assess activity of newborn) for several days after I.V administration of opioids.(4) On the other hand, the presence of larger amounts of medications in the baby can result in a temporary depression of  breathing that may require the attention of a pediatrician. The timing and dosage of medications is usually adjusted to minimize the effect of I.V medications on the new born baby.

1. Cohen SE, Tan S, Albright GA, et al. Epidural fentanyl/bupivacaine mixtures for obstetric analgesia. Anesthesiology 1987;67:403.

2. Viscomi CM, Hood DD, Melone PJ, et al. Fetal heart rate variability after epidural fentanyl during labor. Aesthesia and Analgesia 1987;71:679.

3. Jouppila P, Jouppila R, Hollman A, Koivula A. Lumbar epidural analgesia to improve intervillous blood flow during labor in severe preclampsia. Obstetrics and Gynecology 1982;59:158.

4. Hodgkinson R, Bhatt M, Wang CN. Double blind comparison of the neurobehavior of neonate following the administration of different doses of meperidine to the mother. Can Anaesth Soc J 1978;25;405.

Click below for the next item