Uterine atony


Uterine atony is a loss of tone in the uterine musculature. Normally, contraction of the uterine muscles during labor compresses the blood vessels and reduces flow, thereby increasing the likelihood of coagulation and preventing hemorrhage. A lack of uterine muscle contraction, however, can lead to an acute hemorrhage, as the uterine blood vessels are not sufficiently compressed. Clinically, 75-80% of postpartum hemorrhages are due to uterine atony.

Risk factors

Many factors can contribute to the loss of uterine muscle tone, including:
By abdominal exam to measure the fundal height of the uterus, for normal uterus it should be under the umbilicus after the labor.

Treatment

The first step in management of uterine atony is uterine massage. The next step is pharmacological therapies, the first of which is oxytocin, used because it initiates rhythmic contractions of the uterus, compressing the spiral arteries which should reduce bleeding. The next step in the pharmacological management is the use of methylergometrine, which is an ergot derivative, much like that use in the abortive treatment of migraines. Its side effect of hypertension means it should not be used in those with hypertension or pre-eclampsia. In those with hypertension, the use of prostaglandin F2α is indicated.
Another option Carbetocin and Carboprost where Oxytocin and ergometrin is inappropriate.