Uterine contraction sensing method

An extra-uterine method of sensing uterine contractions of a wearer having a uterus utilizing a non-mechanical sensor which directly converts a change in pressure to a change in electrical signal, the method comprising:

• A. attaching a sensor to the abdomen in the area of the wearer's uterus, said sensor including:
• a rigid outer member, an inner member, and a sensing unit, said sensing unit positioned between said inner member and said rigid outer member, said sensing unit including:
• i. a variable resistor having an outer surface and formed of a pressure sensitive ink;
• and
• ii. a first electrically conductive member interfacing with said ink,
• wherein said inner member rests on the abdomen;
• B. creating a mechanical pre-load on the sensing unit and forcing the first electrically conductive member against the variable resistor outer surface, thereby creating a reference level electrical resistance;
• C. creating a reference level non-decaying electrical signal corresponding to said reference level electrical resistance;
• D. changing the force applied to the first electrically conductive member against the variable resistor outer surface in response to uterine contractions and instantaneously and non-mechanically changing the electrical resistance of the variable resistor, thereby non-mechanically and directly converting a change in pressure to a change in electrical resistance;
• E. creating a non-decaying electrical signal corresponding to said changing electrical resistance;
• and
• F. monitoring uterine contractions by monitoring the electrical signal corresponding to said changing force.