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Dr Marlena du Toit

Vaginal birth after caesarean section (VBAC) PDF Print E-mail

 

Caesarean section is a common surgical procedure. For decades it had been generally assumed that once a woman had a caesarean section, all her future babies would have to be delivered by caesarean section.

However, this concept has changed due to improvements in obstetric care and surgical techniques. Many women who had a caesarean section can safely give birth through the vagina during subsequent labour. This is known as VBAC. With careful selection of patients and good obstetric care, from five to eight women who attempt VBAC are successful.

 

Reasons for VBAC

  • Lower risk of complications (such as bleeding and infection) than routine repeat caesarean section.
  • Other risks associated with surgery are avoided, such as a reaction to the anaesthetic, damage to internal organs, decreased bowel function, and abdominal wound infection.
  • A shorter hospital stay and a quicker recovery.
  • Some women regard vaginal birth as more fulfilling.
  • If successful, VBAC facilitates vaginal birth of subsequent babies, avoiding the risks of repeat caesarean section.
When all possible risks of labour and birth are taken into account, VBAC for an appropriately selected woman has fewer risks of complications than routine repeat caesarean section. However, VBAC may be associated with small but significant risks for the mother and baby.

The decision to attempt VBAC

The decision to attempt VBAC is best made in discussion with your doctor. It will depend on your medical history and the progress of your current pregnancy.
While you have the right to make a decision to attempt VBAC, ultimately your doctor must decide whether or not an attempt is safe. To decide, your doctor will consider four main factors:
  • The location of the uterus scar from the caesarean section incision.
  • Whether the reason for the previous section is still present.
  • How you want to deliver this baby.
  • Your access to a hospital that is well equipped for a emergency caesarean section.

Location of uterine scar

The women most suitable for VBAC have had a horizontal incision (cut) in the lower part of their uterus, known as a lower transverse uterine incision.
The four types of uterine incisions are:
  • Lower transverse – a side to side cut in the lower, thinner part of the uterus where labour contractions are minor; this is the most common incision and is the most suitable for subsequent VBAC.
  • Low vertical – an up-and-down cut in the lower, thinner part of the uterus.
  • High or classical – an up and down or horizontal cut in the upper part of the uterus; more stress is placed on this area during labour than on the lower areas of the uterus.
  • Inverted T-shape incision – this is the weakest scar.

 

You cannot tell where your uterine scar is by looking at the scar in your skin. The uterine scar is in a different position. A doctor needs to see your medical records to determine which type of incision was made.

Another factor is whether the reason for your previous caesarean section is again present in your current pregnancy. If the problem is absent, VBAC might be an option.

Preparations

Some women are enthusiastic about attempting VBAC, while others may be reluctant, especially if a prior caesarean section was performed as an emergency. Discuss your concerns fully and frankly with your doctor because understanding labour and its stages can be helpful. Remember: when you attempt a VBAC you may still need a caesarean section if complications arise.
An intravenous cannula (drip) will be inserted into your forearm as a precautionary measure. You will not necessarily receive fluids through it, but in an emergency it will save time. A catheter will be inserted into your bladder to monitor the blood in the urine (hematuria). The bladder lies adjacent to the uterine scar and bleeding in the scar will lead to blood in the urine and this will serve as a warning sign.
Epidural analgesia can be used during VBAC. However, it may limit mobility and can make it more difficult to push the baby out. Other pain-relief medications such as pethidine can be used or non-drug techniques such as massage and emotional support.

 

 

Unsuitable conditions for VBAC

 

  • The woman has a “classical” scar or an inverted T uterine scar.
  • The position of the uterine scar is unknown.
  • The woman does not want to try a vaginal delivery.
  • Some types of previous uterine surgery, such as fibroid removal.
  • The woman needs induction of labour and has an unfavourable cervix.
  • The woman has an unusual pelvic shape.
  • The baby is in the transverse position (lying across the uterus).
  • The baby appears to be too big to pass through the birth canal.
  • The hospital where you want to deliver is not equipped for an emergency caesarean section.
  • The woman has a medical condition that can complicate labour.
  • Any other contraindication to labour (placenta praevia or breech presentation).
  • Other medical reasons, unrelated to the previous caesarean section may cause VBAC not to be a safe option in the current pregnancy.

Risks of VBAC

VBAC is associated with a small risk of rupture of the uterine scar. This rupture can be caused by the uterus’s forceful contractions during labour and pressure against the scar. Rupture of a uterine scar is an uncommon but serious complication.
The signs of uterine rupture can be difficult to detect. A woman may have some bleeding or continuation of pain between contractions. Changes in the baby’s heart rate are usually the first sign of uterine rupture. This is why continuous electronic monitoring of the baby’s heart is recommended for VBAC.
Rupture of the uterine scar can be life-threatening for mother and baby, and an emergency caesarean section will be necessary.
Rupture of the uterine scar occurs about once n every 200 VBAC attempts. Of those woman who do have an uterine rupture during VBAC:
  • About one woman in 10 of these women will need a hysterectomy (uncommonly, a woman may need a hysterectomy following uncontrollable bleeding during a elective caesarean section).
  • About one birth in 10 births will result in a stillbirth.
Of every 10 women who attempt VBAC, from two to five will need to have a caesarean section. For this reason, VBAC should take place ONLY in a hospital equipped for an emergency caesarean section.
In an emergency, general anaesthesia or regional (spinal of epidural) anaesthesia will be required, depending on which is quicker to administer.
In general, during VBAC, risks for the baby are similar to those faced by babies who are the vaginal first-born to the mother.