[Effect of labor analgesia with ropivacaine on the lactation of paturients]

Abstract

Objective: To examine the effect of labor analgesia with ropivacaine on maternal serum prolactin, time of first colostrum production and the rate of abundant lactation.

Methods: A total of 124 women of vaginal delivery were randomly divided into labor analgesia group (n = 75) and control group (n = 49). Labor analgesia group received ropivacaine by patient-controlled epidural analgesia. Three ml ropivacaine (0.125%) was injected through an epidural catheter and another 12 ml ropivacaine was injected 5 min later if there were no total spinal anesthesia. The block level of analgesia was controlled to be below T10 level. Then 5 ml (0.104 mg/min) ropivacaine per hour was continuously pumped till full dilation of ostium of the uterus. The control group consisted of women of normal spontaneous delivery with no pain relieving measure. The prolactin levels of antepartum, postpartum 0 h, 2 h, 6 h, 12 h and 24 h were determined by microparticle chemoluminescence. Starting time of lactation, the feeding times in 24 hours, the rate of abundant lactation, and neonatal weight 24 hours after delivery were recorded.

Results: (1) The serum prolactin of both groups increased instantly after delivery, reached a peak 2 hours after delivery and kept high levels 24 hours after delivery. (2) The prolactin levels of labor analgesia group [(19.5 +/- 8.4) nmol/L and (14.5 +/- 5.6) nmol/L] were lower than those of control group [(22.6 +/- 7.2) nmol/L and (16.9 +/- 5.7) nmol/L] 2 and 24 hours after delivery (P < 0.05). (3) In labor analgesia group the starting time of lactation was within 24 hours after delivery in 73 cases (97%), lactation amount was abundant within 48 hours in 55 cases (73%) and newborn weight reduction in the first day after delivery was (57 +/- 42) g. In control group the starting time of lactation was within 24 hours after delivery in 45 cases (92%), lactation amount was abundant within 48 hours in 28 cases (57%) and newborn weight reduction in the first day after delivery was (62 +/- 40) g. There were no differences between the two groups in the starting time of lactation, the rate of abundant lactation, and newborn weight reduction (P > 0.05).

Conclusions: (1) Epidural anesthesia with ropivacaine might affect the secretion of prolactin, while the starting time and amount of lactation may be affected by other factors. (2) Prolactin increases after delivery, reaches a peak 2 hours after delivery and maintains high levels 24 hours after delivery, which contented necessary for lactation.