Labour Analgesia and Movement in Babies

The purpose of the study is to investigate the potential utility of actigraphy, a non-invasive means of measuring an individual's movements, in distinguishing the effects of different types of maternal labour analgesia on babies after birth.

The study hypothesizes that actigraphic data can be used to differentiate the effects on neonates of different forms of maternal intrapartum analgesia. In particular, we hypothesize that infants of mothers who receive intrapartum opioid analgesia will demonstrate fewer movements than infants of mothers who receive epidural analgesia or those who receive nothing.

Whilst it is well known that drugs administered to mothers during labour can affect their babies, means of assessing this effect are complex and unreliable. A more objective means of assessing babies after birth is required, and actigraphy may represent a useful technique. Actigraphy has been used on babies in other studies in a variety of settings, including comparing babies born by different delivery modes (i.e. vaginal versus cesarean delivery) and at different gestations (i.e. term versus preterm), although none of these studies have considered maternal analgesia received prior to delivery as a possible influence on babies' movements after birth. Other studies that have looked at sleep parameters in babies, particularly measures of activity, have shown association with later indices of psychomotor development.

The objective of the study is to compare actigraph-derived movement data from babies whose mothers have received any of the commonly used analgesic techniques for labour at BC Women's Hospital.

This is a prospective observational study. Women will be assessed for eligibility for the study on admission to the labour ward. As one of the inclusion criteria is vaginal birth, women considered eligible on admission may become ineligible depending on their mode fo delivery. Information will be available to all women in the assessment rooms and consent will be specifically sought after they deliver and are deemed eligible. We plan to recruit the babies of mothers who receive analgesia in one of four categories: no analgesia or nitrous oxide only; systemically administered opioid analgesia only; epidural analgesia with an intermediate total dose of fentanyl (<150mcg); epidural analgesia with a high total dose of fentanyl (>150mcg). We recognize that women may receive several or even all of the different modalities of labour analgesia in the course of their delivery. In this situation, we will calculate the total dose fo opioid received by all routes and convert this to fentanyl equivalents for the purposes of analysis. Neonates of women who agree to participate will be fitted with an actigraph that will remain in place (except for removal for bathing) for 24 hours, or until discharge from hospital. Actigraphs are small, light-weight, wrist-watch-sized monitors that weight 16 grams. The actigraphs will be placed on the neonates' ankle, as this position has been reported to cause less disturbance to them. Parents of participating neonates will also be instructed in the use fo a daily dairy that will allow correlation of actigraphic movement data with events such as bathing (when the actigraph will necessarily be removed) and other external sources of movements (e.g. being rocked, breastfeeding).