In our February 19 blog post, we discussed the elements of informed decision making. Today we will use the iBRAIN framework to analyze the artificial rupture of the amniotic sac (amniotomy) as a means to speed up labour.
Amniotomy is a procedure performed by a physician or midwife and it involves the artificial rupture of a women’s amniotic sac with the use of a finger or, more commonly, an amniohook. The amniohook is a small, plastic device that looks similar to a crochet needle. During a vaginal exam, the caregiver will insert this hook through the cervix and make a small tear in the amniotic sac. The mother will then feel a gush or trickle of warm liquid as the amniotic fluid leaks out through the hole. This procedure is most commonly used in an attempt to speed up the first stage of labour. It is thought that the added pressure of the baby’s head directly on the lower segment of the uterus will speed up opening (effacement and dilation) of the cervix.An amniotomy hook
- There is no strong evidence to suggest amniotomy alone significantly shortens labour.
- There is some evidence to suggest that early amniotomy, as part of a comprehensive active management of labour that also includes early oxytocin administration and one-on-one care throughout labour, may shorten labour duration by an estimated 70 minutes.
- There is some evidence to suggest that the use of amniotomy may reduce the need for oxytocin (Pitocin) to speed up labour.
- Once the amniotic sac is ruptured, your baby is at a higher risk of developing an infection. Delivery of your baby will be expected to occur in a reasonable amount of time or you will likely have to consider the possibility of oxytocin (Pitocin) administration or even Cesarean birth.
- Early amniotomy has been associated with a higher risk of abnormal fetal heart patterns.
- Even if amniotomy shortens labour duration, there is no strong evidence to suggest shorter labour is beneficial to mother or baby.
- There is potential that if the head is not fully engaged in the pelvis at the time of amniotomy the umbilical cord may slip out of the cervix along with the rush of amniotic fluid. This is a medical emergency that will likely lead to a Cesarean birth. Because of this, healthcare providers will not perform am amniotomy if the baby’s head (or presenting body part) is not fully engaged.
Note that each of the following alternatives has a set of risks and benefits. Some of these alternatives will be reviewed in future posts. Be sure to talk to your doctor or midwife if you have questions.
- Upright positions and walking
- Empty bladder
- Breast/nipple stimulation
- Pitocin (synthetic form of oxytocin, the hormone that stimulates contractions)
Women who choose not to undergo an amniotomy will continue to labour. Unless there is a specific medical reason to shorten labour (i.e. – fetal or maternal distress), the most current recommendation is to avoid amniotomy as benefits do not outweigh potential risks in healthy moms and babies.
(1) Smyth RMD, Alldred SK, Markham C. Amniotomy for shortening spontaneous labour. Cochrane Database of Systematic Reviews 2013, Issue 1. Art. No.: CD006167. DOI: 10.1002/14651858.CD006167.pub3
(2) Wei S, Wo BL, Qi HP, Xu H, Luo ZC, Roy C, Fraser WD. Early amniotomy and early oxytocin for prevention of, or therapy for, delay in first stage spontaneous labour compared with routine care. Cochrane Database of Systematic Reviews 2012, Issue 9. Art. No.: CD006794. DOI: 10.1002/14651858.CD006794.pub3.
(3) Simpson KR and Creehan PA. Perinatal Nursing. 2008. AWHONN.