During labor assessment, which contraction amplitude would indicate hypotonic labor?

In the context of labor assessment, hypotonic labor is characterized by contractions that are insufficient in strength and frequency to facilitate effective cervical dilation or fetal descent. Amplitude is a measurement of the strength of contractions, typically assessed through an intrauterine pressure catheter.

When the amplitude of contractions is less than 20 mm Hg, this indicates weak contractions that would not provide the necessary force to promote the progress of labor. This low level of contraction strength can lead to prolonged labor and may require intervention, as effective contractions are typically within a higher amplitude range.

In contrast, higher amplitudes, such as those in the ranges of 40-50 mm Hg, 60-80 mm Hg, or over 80 mm Hg, would represent stronger and more effective contractions, which are associated with normal labor progression. Therefore, identifying contractions with an amplitude of less than 20 mm Hg is key in recognizing hypotonic labor and determining the need for further evaluation or intervention.