Complex sentence: Sharon realised that there was a need for tiny baby clothes to fit babies born too soon, that could accommodate the necessary leads, wires and monitoring equipment used in SCBU, HDU or NICU.
Split into simpler sentences: Sharon realised that there was a need for tiny baby clothes to fit poorly babies or those born too soon. The clothing needed to accommodate the necessary leads, wires and monitoring equipment used in SCBU, HDU or NICU.