Tuesday, March 17, 2009
VBAC and Scar Integrity
VBAC and scar integrity,
or "Why my uterus isn't going to explode"
Myth: It takes two years or more for uterine scar tissue to heal.
Fact: Your uterus is just like any other cut that is bound with stitches or staples, and does all the healing it's going to in the first few weeks. While a few studies suggest that the risk of rupture (more on what "rupture" is later) is higher if you get pregnant within 18 months, it is still far less than 1%, and while it is often recommended to wait, this does not reflect whether or not a real risk exists following initial healing. Most authorities agree that by the time your fertility returns (2-3+ months), conception happens and the uterus begins to expand (12 weeks), healing is done. The gentle pressure of a slowly expanding uterus is unlikely to cause any damage, and since we don't go into labour immediately following conception it's likely a year or more would have passed since the surgery. Healing can continue even during pregnancy.
(taken from Birthlove.com)
From BIRTH AFTER CESAREAN by Bruce Flamm: "Rumor has it that its safer to wait several years after a cesearen section before attempting a vaginal birth. There's absolutely no evidence for this belief. Studies on wound healing have shown that tissue regains the majority of its strength within a few weeks of an operation. The tissue that gives a healing wound its strength is called collagen. According to a general surgery textbook, 'Collagen content of the wound tissues rises rapidly between the sixth and the seventeenth days but increase very little after the seventeenth day and none at all after the forty-second day.' Since the uterine scar is almost fully healed within weeks after a cesarean section there is no reason to postpone plans for another baby."
Myth: If you rupture, you and your baby will die.
Fact: Catastrophic ruptures are extremely rare, and much more likely if you have oxytocin induction, cyotec, prostaglandins or lay flat on your back unable to move around. Included in rupture statistics is harmless and asymptomatic dehiscences, which unfairly skews the numbers. When people think of rupture they think of a uterus imploding, they don't think of scar tissue pulling away from where it's gotten stuck, or a small break that heals easily and poses no risk to mother or baby. Dehiscences are the most common type of "rupture", by far. It is usually diagnosed when a second c-section is performed or the doctor physically puts his hand inside a woman's uterus and feels around after birth. Some evidence suggests that many dehiscences actually occur before labour begins.
Catastrophic rupture (the dangerous kind) more often happens due to uterine integrity as a whole (with the vast majority following labour augmentation). The cases of true rupture are not the 1-2% figure we hear all the time, that is for dehiscences. When a true rupture occurs, a cesarean must occur within 30 minutes (ideally 20) to prevent neurological damage to the baby. Death does not occur immediately. Most women attempting a home VBAC are well within 20-30 minutes of a hospital, particularly if 911 is called.
'A Guide to Effective Care in Pregnancy and Childbirth', which is a well-respected summary of evidence-based practice, says that the rate of reported uterine rupture has ranged from 0.09% to 0.8% for women with a single baby, head-down, who planned a vaginal birth after one previous lower-segment cesarean. The authors comment:
"To put these rates into perspective, the probability of requiring an emergency cesarean section for acute other conditions(fetal distress, cord prolapse, or antepartum hemorrhage) in any woman giving birth, is approximately 2.7%, or up to 30 times as high as the risk of uterine rupture with a planned vaginal birth after cesarean"
What does this mean for women who want a VBAC? Up to 99.91% of you will labour normally.
True rupture is not asymptomatic, and the first signs are a steadily falling heart rate (now heavily debated over whether or not this is a true indicator) and/or intense pain that you'll feel even with an epidural. While external fetal monitors, in theory, are meant to catch this kind of thing as it happens - they often do not. External fetal monitoring has not been shown to save any lives, and has only been shown to increase the amount of unnecessary c-sections being performed. It is just as effective, and safer overall, to have a nurse or midwife come in every so often and have a listen with the doppler or fetoscope - particularly during a contraction. This also keeps you off your back, where you are often strictly told to stay if you are hooked up to EFM. This position increases your chances of complications. Move around! Stay hydrated! Stay strong! Avoid drugs! Labour isn't made so you that you can lie back with your feet up.
Home dopplers and fetoscopes are available to rent or buy. Fetoscopes can be purchased online or at any medical supply store for $30 or under, and home dopplers can be rented for as little as $35-$40 a month. Do keep in mind that dopplers, being ultrasound, carry risks. A fetoscope poses no risk to the baby.
Risk of rupture also depends on the type of incision you received. Except in rare cases, modern c-sections are performed by low transverse incision (a horizontal scar just along your pubic bone, usually hidden by a bikini). The risk is highest with a vertical incision over the middle of the stomach. This requires more healing time as well.
Overall, attempted vaginal birth for women with a single previous low transverse cesarean section is associated with a lower risk of complications for both mother and baby than routine repeat cesarean section. The morbidity associated with successful vaginal birth is about one-fifth that of elective cesarean. Failed trials of labor, with subsequent cesarean section, involve almost twice the morbidity of elective section, but the lower morbidity in the 80% of women who successfully give birth vaginally means that overall women who opt for a planned vaginal birth after cesarean suffer only half the morbidity of women who undergo an elective cesarean section.
What does this mean? A repeat c-section is more dangerous than a VBAC. The problem is we don't hear that very often. Some women are only ever offered a repeat c-section by their doctors. If they are truly only ever done in event of "emergencies", how can one justify the risk of denying a woman a VBAC when it is clearly the safest route for both mother and baby?
A 10-year population-based study of uterine rupture.
Obstet Gynecol 2001 Apr;97(4 Suppl 1):S69
Baskett TF, Kieser KE.
Dalhousie University, Halifax, Nova Scotia, Canada
Objective: To review the incidence, associated factors, and morbidity associated with uterine rupture.Methods: A 10-year (1988-1997) population-based review of 114,933 deliveries in one province.
Results: There were 39 ruptures: 16 complete and 23 dehiscence. Thirty-seven cases had undergone a previous cesarean delivery (34 lower transverse, 2 classical, 1 low vertical). Of the 114,933 deliveries, 11,585 (10%) were to women with a previous cesarean delivery. The incidence of uterine rupture in those undergoing a trial for vaginal delivery (4,516) was complete rupture (3/1000) and dehiscence (5/1000). Induction or augmentation of labor with oxytocics was associated with 50% of complete ruptures and 25% of dehiscence. There were no maternal deaths, but 33% of patients with complete ruptures required blood transfusion. There was one neonatal death attributable to uterine rupture.
Conclusion: Induction and augmentation of labor are confirmed as risk factors for uterine rupture. Fetal heart rate abnormality was the most reliable diagnostic aid. Serious maternal and perinatal morbidity was relatively low. PMID: 11275210
Shamelessly stolen from Norwegian_wood's journal:
Here are some statistics to put the risk of rupture in perspective:
* Your risk of rupture from a horizontal LSCS scar is: 1% = 1 in 100 VBAC deliveries (this is the highest statistic)
* Your risk of being diagnosed with dystocia (baby too big) is: 10 - 12% = 10 in 100 vaginal deliveries
* Your risk of a breech baby at full term is: 3 - 7% = 3 in 100 deliveries
* The risk of your baby being diagnosed with fetal distress during labour: 2% = 2 in 100 deliveries
* Your risk of having twins is : 0.4% = 4 in 1000 births
* Your risk of dying from a rupture of the uterus is: 0.0095% = 9.5 in 100 000 VBAC deliveries
* Your risk of dying during any vaginal delivery is: 0.0098% = 9.8 in 100 000 vaginal deliveries
( re-read that one, "Your risk of dying in ANY vaginal delivery is 9.8 in 100,000, compared to a death risk of 9.5 in 100,000 with a VBAC" )
* Your risk of dying during an uncomplicated vaginal delivery is: 0.0049% = 4.9 in 100 000 uncomplicated vaginal delivery.
* Your risk of dying during any ceasarean section is: 0.0409% = 40.0 in 100 000 ceasarean sections
* Your risk of dying during an elective repeat ceasarean section: 0.0184% = 18.4 in 100 000 elective csecs
* The risk of your baby developing cerebal palsy is: 0.25% = 2.5 in 1000 births
* The risk of your baby developing cerebal palsy after fetal distress: 2.84% = 2.8 in 100 fetal distress births
* The risk of your baby dying from a rupture of the uterus is: 0.095% = 9.5 in 10 000 VBAC deliveries
* The risk of your baby dying during any VBAC delivery is : 0.2% = 2 in 1000 VBAC births
* The risk of your baby dying during any type of delivery is: 0.12% = 1.2 in 1000 births
Articles & Links:
Vaginal Birth after 2 or More Cesareans An excellent and informative research-based read analyzing studies, pitocin use and risks of true ruptures versus that of dehiscences. Addresses risks in both VBA1C and VBA2+C.
Twin VBAC not associated with increased risk of rupture
VBAC safe for women with twin pregnancies
Mothering: Fighting VBAC-lash
The Integrity of Caesarean Scars - Originally posted as a reply in a forum, is now an article with a thought-provoking look at the idea that the uterus doesn't heal the same way the rest of the human body does.
Mothering: Cesarean and VBAC index
Birthlove: VBAC is safe!
ICAN: International Cesarean Awareness Network
For those of you convinced that a doctor would only ever have your best interests in mind, I suggest you read articles like this one published in October 2000 entitled, "Getting a Stubborn Patient to Say Yes". This article has since been reposted in many VBAC communities to make women aware of the manipulation tactics that may be used against them.
Don't take your doctor's word for it when he says, "You can't have a VBAC" or, "A VBAC is dangerous". Don't take anyone else's word for it when they say "no one in this town will let you have one". Interview, ask, push and shove - you have the right to the safest birth for your baby. Many midwives will oversee a home, center or hospital VBAC and you can switch to a midwife at any point during your pregnancy, even when your due date is approaching.
Remember, home is safest as far as your risk for dangerous interventions. There's no chance of pitocin induction, epidurals or being kept on your back when you're pacing your own bedroom. Homebirth has been proven to be as safe if not much safer than hospital birth.
Read, educate and inform yourself of the facts so you can be prepared the next time someone tries to scare you out of the best birth for your baby with myths and wives tales. Knowledge is power.