ARM is Artificial Rupture of Membranes, otherwise known as Amniotomy.

It involves splitting of the amnion and chorion (membranes) to release Liquor.
This is done using an amnihook (a tool, with a small hook on the end), and as with all procedured carried out on the woman-requires informed maternal consent. This should be clearly given and the reason for the ARM clearly stated in the maternity records.

Prior to performing an ARM, the practioner should palpate the uterus confirming presentation, and degree of engagement of the presenting part, the fetal heart should also be auscultated prior to the procedure.
Firstly a vaginal examination (VE), is carried out to assess dilation and to ensure no cord is presenting in front of the presenting part/alongside it, and the midwife should have firstly checked scan reports to ensure the placenta is not low-lying.

The membranes over the presenting part are ruptured, the colour and quantity of Liquor are noted, as are presention, position, and station of the fetus aswell as a further asessment ensuring no cord has prolapsed. The midwife will often run fingers all the way round the presenting part (which should be cephalic/head) to rule out cord prolapse and to ensure the head is closely applied to the cervix.

On completion of this the fetal heart should be auscultated once more.
So how is it done? The fingers are left in the vagina at the presenting part following the examination, and the amnihook is opened and slid between the fingers to ensure the hook does not 'catch' the vaginal wall, most midwives seem to wait till a contraction has built up so the membranes are bulging, thus easier to rupture.

VERY IMPORTANT- to ensure it is cephalic, and that the membranes are intact-I have seen babies with scratches on them as a result of ARM with a woman who has already had SRM (spontaneous rupture/ Waters gone).
Why is it done??

It is commonly performed as part of the process of induction of labour. It is usually performed after the use of one or more doses of prostin. If a woman is booked for prostin induction but has a favourable cervix on the Bishops score (usually a multip i.e has already given birth) then instead of prostin induction you may hear the term "she is ARMable" thus meaning they will take her to delivery suite to perform this.

ARM allows the presenting part to descend, improving application to the cervical os. This increased stimulation causes more pain to the woman, as contractions are stronger, as levels of prostaglandins rise, it is also said to shorten labour, however Lavender states it only shortens duration for an average of 37mins so a little unfair for all that extra pain for the woman!!
That said some women seem to want their " Waters broken" and tend to progress very quickly.

ARM may be used on its own or with oxytocin, as oxytocin induction should never be started without prior rupture of the membranes.
It may be carried out to visualise the colour of the Liquor, or to attach a fetal scalp electrode for the purpose of continous electric fetal monitoring of the fetal heart.

Potential problems with amniotomy include:

• intrauterine infection from digital or instrumental examination.
• early decelerations of the fetal heart
• cord prolapse
• bleeding from fetal vessels (as in Vasa Praevia), vessels in the cervix, low-lying placenta ( Placenta Praevia)

Attached Images

	ARM.jpg (5.5 KB, 13 views)
	amniohookclose.jpg (10.3 KB, 8 views)

Debate and Discussion for this glossary topic can be carried out here:-
Artificial Rupture of Membranes Debate and Discussion

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