Sunday June 17, 2012
THE DOCTOR SAYS . . .
By Dr MILTON LUM
Depending on various factors, vaginal birth after a Caesarean section is still possible.
ACCORDING to the National Health Care Establishments & Work Force Statistics published in 2011, the overall Caesarean section (CS) rate in 2009 was 20.8% of all deliveries. The CS rate was 30.3% in the private sector and 18.1% in the public sector. The overall CS rate in Kuala Lumpur was the highest at 29.5%, compared to 11.5% and 11.6% in Sabah and Kelantan respectively.
The question that everyone who has had a CS asks is how to give birth in the next pregnancy. One could have a vaginal birth or an elective CS.
In order for the obstetrician to provide the appropriate recommendation, he or she considers the reason(s) for the previous CS and what happened, the type of uterine incision made, whether there are any complications in the current pregnancy, and the views of the patient about the previous CS and current pregnancy.
Vaginal birth can mean a normal delivery or an assisted delivery with a forceps or ventouse. VBAC is an acronym for vaginal birth after Caesarean. The alternative is a planned CS, which is usually done at 39 weeks gestation, ie a week prior to the estimated date of delivery, unless there are maternal and/or foetal reasons for an earlier delivery.
Both VBAC and planned CS have risks, which are small.
Attempting a VBAC is not done when the mother has had two or more previous CS, rupture of the uterus in a previous pregnancy, a classical CS (the uterine incision is vertical) done previously or there are pregnancy complications in the current pregnancy that necessitate a CS, eg mother’s pelvis is small in relation to the size of the foetal head, or medical conditions like a heart problem.
In such situations, the obstetrician would advise a planned CS.
Advantages and disadvantages of planned VBAC
The advantages of a vaginal birth are increased likelihood of vaginal birth in future pregnancies, less abdominal pain, and no surgery, with consequent shorter recovery period and hospital stay.
There are disadvantages of a planned VBAC. One is unplanned CS, which occurs in about 25 out of 100 women. This is slightly more than the likelihood of CS if one is in labour for the first time, which is about 20 out of 100 women.
An unplanned CS may be done for various reasons, ie concerns about maternal or foetal health, labour is not progressing, failed induction, or going into labour before a planned CS.
Another disadvantage is the possibility of an opening appearing in the previous uterine scar (uterine dehiscence) during labour, which can lead to the scar splitting open (uterine rupture). This is potentially life-threatening for mother and foetus. It occurs in two to eight out of 1,000 women.
The likelihood of uterine rupture is increased if the previous uterine incision was vertical (20 to 90 out of 1,000 women), or if labour is induced.
The likelihood of uterine rupture in women who have had a previous surgical removal of fibroids (myomectomy) is unknown as data is lacking and contradictory. If signs of possible uterine rupture are detected, an emergency CS will be carried out.
The likelihood of having a blood transfusion in VBAC or infection is one out of 100 women when compared to a planned CS.
The likelihood of brain damage or death to the foetus in VBAC is two out of 1,000 women, which is similar to that of someone experiencing her first labour. This is in comparison to a likelihood of one out of 1,000 women in those who have a planned CS.
However, there is a need to balance this with the risks of a planned CS, which is discussed below.
There is no difference in risks between planned VBAC and CS in relation to hysterectomy, thromboembolic disease or maternal death.
There are increased risks with unsuccessful VBAC when compared to successful VBAC in that there is an increased risk of uterine dehiscence, uterine rupture, hysterectomy, transfusion and uterine infection.
Advantages and disadvantages of planned CS
The advantages of a planned CS include avoidance of the risks of labour, especially the one in 1,000 likelihood of foetal brain damage or stillbirth; almost no risk of uterine rupture; convenience and knowledge; and perhaps, choice of date of delivery.
As planned CS is usually done at about 39 weeks’ gestation, there is a one in 10 chance of going into labour prior to the pre-arranged date.
There are disadvantages of a planned CS. The obvious risks are the consequences of surgery. The risks to the mother include infection of the wound and/or the uterus, excessive bleeding, which may require removal of the uterus (hysterectomy), damage to the bladder or the tube that connects the kidney to the bladder, blood clots (thrombosis) in the legs or pelvis, which may be life-threatening if part of it dislodges and goes to the lungs (pulmonary embolism), and longer hospital stay.
In addition, the surgery will take a longer time and may be more difficult, with an increased risk of accidental injury to other abdominal organs, usually the bladder or bowel. This is usually due to the scar tissue from the previous CS.
There are also risks to the baby. Accidental cuts on the baby’s skin when the uterus is incised occur in about two in 100 babies delivered by CS.
The most common risk is that of breathing difficulties, which occur in about 35 in 1,000 babies delivered by CS, compared to five in 1,000 babies delivered vaginally. Their breathing may be more rapid immediately after birth and the first few days of life (transient tachypnoea). This usually resolves within two to three days. The risk of baby’s admission to the intensive care unit may also be increased.
The risks of anaesthesia to mother and baby have to be considered too.
The time needed to recover from a planned CS is more than that of a planned VBAC.
A planned CS will also be need-ed in subsequent pregnancies. Furthermore, the increased formation of scar tissue with each CS leads to an increased likelihood of the placenta in a subsequent pregnancy embedding into the scar and adhering morbidly to it (placenta accreta). This can result in increased bleeding risk, and even, a hysterectomy.
Management of pregnancy and labour after a previous CS
According to the guidelines of the Royal College of Obstetricians and Gynaecologists of the United Kingdom, the management of women who have had one previous CS is: “Women who have had an uncomplicated lower-segment transverse CS, in an otherwise uncomplicated pregnancy at term, with no contraindication to vaginal birth, should be able to discuss the option of planned VBAC and the alternative of a repeat CS. A final decision for mode of birth should be agreed between the woman and her obstetrician before the expected/planned delivery date (ideally by 36 weeks of gestation). A plan for the event of labour starting prior to the scheduled date should be documented.
“Women considering their options for birth after a single previous Caesarean should be informed that, overall, the chances of successful planned VBAC are 72–76%.”
In order to have a safe labour after previous CS, a woman should be delivered in a hospital where immediate Caesarean section can be carried out. The woman and her obstetrician must be aware of the hospital’s resources, especially the availability of obstetric, anaesthetic, paediatric, and operating theatre staff 24 hours daily, 365 days a year.
The hospital should have a written policy regarding the processes for a possible immediate CS. An appropriate time frame of 30 minutes is considered adequate in the majority of instances.
Continuous electronic foetal monitoring of women attempting a VBAC is recommended.
The management of labour is similar to that of normal labour, with the proviso that oxytocic drugs have to be used judiciously.
It would be prudent for women who have had a previous CS to consult their obstetrician upon knowing that they are pregnant, to discuss the benefits and risks of a planned VBAC or planned CS, and to agree to a plan for managing their labour and delivery.
There must be willingness to accept a change in the delivery plan. This arises because of an alteration in the balance of risks and benefits consequent to a change in circumstances during pregnancy and/or labour.
In summary, the dictum “once a Caesarean, always a Caesarean” does not hold true in the majority of women who have had a previous CS, as three-quarters of women who have a planned VBAC achieve their objective.
There are many advantages of a planned VBAC in women whose current pregnancy is uncomplicated.
■ Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organization the writer is associated with.