User Guide

100-PT-056 rev1
Monica Healthcare Ltd. Unit 8, Interchange 25 Business Park, Bostocks Lane, Nottingham, NG10 5QG, UK
www.monicahealthcare.com
A Guide to Monitoring Contractions with Monica Devices
Monica detects the electrical activity of the myometrium to monitor uterine contractions
(UC). Uterine electrical activity, consisting of infrequent and low amplitude EHG
(electrohysterography) bursts which occur throughout most of pregnancy, but do not
generally result in contractions that are perceived by the patient. In late pregnancy, these
bursts often correspond to periods of perceived contractility by the patient (Braxton Hicks
contractions). During both term labour and preterm labour, bursts of EHG activity are
frequent, of large amplitude, and are correlated with large changes in intrauterine pressure
and pain sensation
i
.
Monica reliably identifies UC during active labour. Currently it is not able to determine
contraction strength
ii
. In established labour, Monica EHG technology is more reliable and
has higher sensitivity than tocodynamometry
iii iv
. Nevertheless false positive UC can occur
on occasion from various sources;
1. Low-level or uncoordinated EHG activity not associated with an increase in
intrauterine pressure appear as small irregular deflections from the baseline. These
are easily identified during labour among the larger more regular ‘true’ contractions.
2. Maternal activity or vigorous fetal movement can change maternal abdominal surface
contours and produce what appears on the trace to be a UC. This is caused by small
changes in the electrode positions in relation to each other and to the underlying skin.
This may create confusion particularly during antepartum and early induction
monitoring, when regular true contractions are not present.
Before any definitive clinical interpretation of UC information generated by Monica is made,
ensure, if possible that the patient is not moving and is in a comfortable and relaxed
position. If there is concern about false positive contractions during early labour or
induction, it can be helpful to have the patient use the event marker either on the AN24 or
Doppler CTG monitor to indicate when she feels a contraction and/or the fetus move.
Irregular high amplitude ‘ragged’ looking contractions that are coincidental with fetal or
maternal movements with no other clinical indication of UC should be discounted. They are
unlikely to be real contractions. As such, they should not influence medical intervention
unless corroborated by another device.
Using Monica UC provides a wireless and beltless solution that is more comfortable for the
patient than tocodynamometry (TOCO). Once the electrodes are on the abdomen they do
not need to be readjusted. This is different from TOCO which often requires adjustment of
transducer position and belt tension. The belts themselves can be uncomfortable for the
patient. In addition, in obese patients tocodynamometry can be very difficult and Monica
can offer a solution in monitoring this cohort of women
v
. TOCO does not provide an
accurate measurement of the intensity and duration of the uterine contractions
vi vii viii ix x
.
When using either TOCO or Monica, interpretation of the UC pattern should be done in the
clinical context of the patient. It is always good practice to use manual palpation, maternal
perception of UC and observation in conjunction with any UC monitoring device.
xi xii