Mary Cronk's thoughts on early detection of scar problems during VBAC
Mary Cronk MBE, has been a midwife since the early 60s and been practicing independently since
1990, has extensive experience of caring for VBAC and HBAC women. She discusses
ways she feels she can enhance the safety of such women.
I have had quite a few women with CS scars on my caseload and while the risk of
scar problems is low 1% or less in a spontaneous labour it does exist. This woman's
uterus has been compromised. I do a few things in addition to standard care for VBAC women.
- At around 20+ weeks I am not surprised if the woman complains of stabbing or
burning sorts of sharp lower abdominal pains. This is not uncommon and is I think
due to breaking down of small adhesions and the consequent leakage of a few
drips of serous fluid onto the peritoneum with the resultant pain. I ask
the woman to remember the feeling of these pains and explain what I believe
to be the cause. One has of course to be sure that one is not missing a urinary
tract infection (UTI) or even an appendicitis and I would not hesitate to get a medical
opinion if the pain/discomfort was more than very brief.
- I am not usually too bothered about routine ultrasound scanning as I am
unconvinced that it improves outcomes. However as we know that one of the
problems can be difficulty with the placenta if it has attached itself to
the previous scar, I think a placental localisation scan around 35-36 weeks
can be helpful and enable one to anticipate needing to transfer for help if
the placenta is reluctant to separate.
- I take and record the woman's pulse rate during antenatal visits in the
last month. This identifies the woman's normal pregnant pulse rate, and as
I take the matenal pulse frequently in labour I have a prelabour datum. I
have been surprised at just how fast pregnant women's pulses are, 84-96
being not uncommon, whereas in her non pregnant state it might have been
- During the last month or so of the pregnancy, I ask the woman to feel her
abdomen and get to know how her scar feels. Are there any bits that are
lumpy or a bit tender? In addition to having the woman know her scar,
I have found that doing this can sometimes lead her to talking about her
feelings about the previous CS and help us work through issues. I have cared for a
woman who when I suggested that she felt her scar burst into tears and
told me she had NEVER done so! We did a lot of work together and she had a lovely home
- In the labour, which is hopefully spontaneous at term (approx 37-42 weeks),
I ask to be called sooner rather than later. In addition to the usual observations I
take her pulse every 10 to 15 minutes to establish a baseline and I record
it. Depending on what is happening I may or may not stay, but if I feel
that labour is established I would stay. I make a nuisance of myself taking
her pulse and I increase the frequency of this observation as the labour intensifies.
It is not a totally reliable sign but should there be any dehiscence there
is often a rapid increase in pulse rate and in my opinion it is worth doing.
The mechanism is that any dehiscence or even overstretching of the scar can
cause a leak of serum onto the peritoneum causing the surgical shock reaction
resulting in an increase in pulse.
- I ask the woman to prod her scar as she knows best how it feels and
tell me if anything gets different from usual. I also ask her to let me know if she has
any pain between contractions particularly a pain that feels like the adhesion pains that
she might have had at 20 weeks or so.
I believe all these signs and symptoms may identify a scar problem long, long before there
would be any deterioration in the fetal heart rate. I know the received wisdom is that the CTG will
pick up the fetal distress caused by a ruptured uterus and I know that acute rupture
CAN happen but vigilant quiet careful observation of the mother can usually identify
potential problems long before the baby is affected. These extra observations I am suggesting
are of course in addition to the usual observations
of fetal welfare and labour progress that one makes during any labour.
Mary Cronk June 2005
- serum - fluid from tissues in the body
- peritoneum - the membrane lining the abdominal cavity
- surgical shock - you may know surgical shock as the condition that first aiders are
taught to look out for if someone has had an injury such as a severe cut or burn - other symptoms
including pale face, cold clammy skin, fast or shallow breathing, etc. may be difficult to detect
in a labouring woman
- CTG - Cardiotocography - electronic fetal monitoring