The Effect of Neuraxial Analgesia on Maternal Breastfeeding

Overview

A previous randomized trial showed a possible negative association with labor neuraxial analgesia with high compared to low doses of fentanyl, and breastfeeding at 6 weeks postpartum. The significance of this study would be to validate or refute these findings. In addition, we hope to better evaluate the impact of cumulative dose of fentanyl on breastfeeding success in the initial postpartum period as well as at 6 weeks and 6 months post delivery. In order to better assess the quality of breastfeeding, we will utilize a validated breastfeeding assessment tool, LATCH (Latch, Audible swallowing, Type of Nipple, Comfort, and Help). This validated tool can assess maternal and infant variables, define areas of needed intervention, and determine priorities in providing patient teaching. The LATCH assessment has been shown to be a predictor of breastfeeding duration. We also plan to vary the dosage of fentanyl analgesia to determine the relationship between doses below 150 micrograms and changes in breastfeeding assessments. If a clear association between decreased breastfeeding and total fentanyl is identified, then regimens to reduce cumulative doses of fentanyl can be developed to improve the likelihood of breastfeeding success in mothers that desire to breastfeed. Prior observational studies have inferred epidurals negatively affect breastfeeding by decreasing maternal plasma oxytocin release which may adversely affect infant neurobehavioral development. In a study by Beilin et al., it was reported that mothers receiving a high cumulative dose (\> 150 microgram) epidural fentanyl were more likely to have stopped nursing 6 weeks postpartum compared with groups receiving no fentanyl or those receiving \< 150 microgram. The study however, was underpowered to detect differences in breastfeeding prior to hospital discharge. In addition, the breastfeeding assessment tool utilized resulted in binary assessments, and therefore, a global rating of the quality of breastfeeding was not available.

Participants in this study will be asked to complete a questionnaire called the Intrinsic Motivation Inventory (IMI). Subjects will be randomized at the time they request neuraxial analgesia to one of three groups: Group 1: patient controlled epidural analgesia (PCEA) with bupivacaine 1mg/mL; Group 2: PCEA with fentanyl 1 mcg/mL plus bupivacaine 0.8 mg/mL; Group 3: PCEA with fentanyl 2 mcg/mL plus bupivacaine 0.625 mg/mL. Labor analgesia will be initiated in all groups using fentanyl 15 mcg plus bupivacaine 2.5 mg administered intrathecally. A basal infusion rate for the PCEA will be set at 8 mL/h with patient administered boluses of 8 mL every 10 minutes and a one hour limit of 32 mL. Breakthrough pain in all groups will be managed using anesthesiologist administered boluses of bupivacaine 1.25 mg/mL without fentanyl. The patient as well as individuals who evaluate the study patient will be blinded to the group assignment. Samples of maternal venous blood ½ teaspoon (2 mls) and cord blood 2ml (1/2 teaspoon) will be collected after the delivery of the fetus. Blood concentrations of fentanyl and bupivacaine will be ascertained using high performance liquid chromatography (HPLC) analysis. Success of breastfeeding using the LATCH assessment tool will be measured by the lactation nurses within 24 hrs of delivery. At 6 weeks and at 3 months postpartum, follow-up phone calls by the anesthesia service will be made to assess for duration of breastfeeding. Also, the patient's obstetrician will be contacted to obtain the patient's Edinburgh Postnatal Depression Score to assess for postpartum depression, which may be a variable in decreasing breastfeeding success.