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Maybe you’ve been told VBAC won’t be possible because of the pandemic. Or maybe you are wondering if VBAC is a good idea.
Is the pandemic a legitimate reason for abandoning plans for VBAC?
In a word: “No.”
With proper management, your odds of cesarean should be about 25% or 1 in 4 and better than that if you’ve had a vaginal birth before or after a cesarean. Even when maternal history and obstetric factors are suboptimal for VBAC, half or more of planned VBACs should result in vaginal birth, but a planned cesarean puts your odds of cesarean at 100%. Here are four reasons to avoid a cesarean if possible:
But what if you’re being told you aren’t allowed a VBAC? That’s flat out wrong on two counts.
First, it contradicts COVID-19 guidelines. No guideline recommends treating women with no current indication for cesarean any differently than before the pandemic, and not one singles out women with prior cesareans as an exception. Furthermore, a joint statement on elective surgery by multiple U.S. professional organizations, including the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine, endorses the U.S. Centers for Disease Prevention and Control’s recommendation to cancel elective surgical procedures when case rates are high. They probably didn’t have elective repeat cesarean surgery in mind, but it would, by definition, fall into this category.
Second, VBAC denial violates your human rights. The Joint Commission, which regulates U.S. hospitals, says this in their patient’s rights pamphlet:
However, while VBAC may be your right, enforcing that right when your doctors or hospital don’t agree puts you in a tough spot. These are the people in whose judgment and care you should be able to trust, something highly doubtful if they think you shouldn’t be trying for a vaginal birth and aren’t happy with you for thinking that you should.
What to do?
So, what are your options if your care providers, hospital, or both don’t allow VBAC?
For more on the comparative safety of planned VBAC versus repeat cesarean, your individualized likelihood of VBAC, and how to maximize your chances of an uneventful VBAC, see Childbirth U’s masterclass “Vaginal Birth after Cesarean?”
Taking a Deeper Dive
Labor induction as usually administered increases the likelihood of the uterine scar giving way; however, safe labor induction is possible.
Studies of typical VBAC induction management consistently find an increase in uterine scar ruptures when labor is induced. These studies fall into three groups: studies comparing labor starting on its own with induced labors not using prostaglandin E2 (PGE2), a cervical ripening agent, in other words, studies where the cervix was ready enough for labor that cervical ripening agents weren’t needed; studies comparing labor starting on its own with induced labors involving PGE2; and induced labors involving versus not involving PGE2. Note: I didn’t include studies of VBAC labors involving misoprostol, A.K.A., Cytotec, the other cervical ripening agent in common use, because it is associated with such a high scar rupture rate that it is contraindicated in VBAC labors.1
Ten studies compared labor starting on its own with induced labors not involving PGE2, that is, where cervical ripening was deemed not needed.6, 7, 11, 17, 23, 25, 26, 30, 35, 43 Nine of the 10 reported more scar ruptures with induction. Differences ranged from 2 to 19 more scar ruptures per 1000. The tenth study had both an unusually low scar rupture rate and too few women in the induction group to reliably detect a difference.
Ten studies compared scar rupture rates in labor starting on its own with induced labors involving PGE2, that is, cervical ripening was needed.6, 11, 12, 23, 25, 26, 31, 35, 42, 43 Of them, seven reported increased risk with PGE2 ranging from 6 to 46 more scar ruptures per 1000. Of the three that didn’t find an increase, two were too small to have the power to reliably detect a difference, and the third reported extraordinarily low scar rupture rates in both groups.
Seven studies compared induction with PGE2 versus induction without PGE2. All found an increase with inductions involving PGE2.11, 23, 25, 26, 35, 40, 43 Differences ranged from 2 to 92 more scar ruptures per 1000 with PGE2. As to why PGE2 is more problematic for the scar, it may have to do with a direct effect of PGE2—it ripens the cervix by softening connective tissue, but the scar is also connective tissue—or because PGE2 use is a marker for an unripe cervix, or it could be a combination of both. This may also explain misoprostol’s deleterious effect on the uterine scar.
A study that was the exception to the rule suggests that the excess risk may have to do with how labor inductions are managed. The authors report that the scar rupture rate was 3 per 1000 regardless of whether labor was induced or started on its own.31 They attribute this to their induction protocol. Contrary to what is typical, oxytocin to stimulate contractions was not permitted with an unripe cervix, PGE2 was given a longer time (40 hrs) to ripen the cervix, a longer interval (12 hr) between PGE2 doses was mandated, oxytocin to strengthen labor could only be administered once the baby’s head below the pelvic brim (engaged) and cervical dilation had exceeded 3 cm, and PGE2 was not permitted when women had multiple prior cesareans or a twin pregnancy. I would also add that the protocol dictated a 40-minute wait after increasing the oxytocin dose before increasing it again, which allows the current dose to reach its full effect. Moreover, using this conservative approach did not decrease VBAC rates compared with other induction or augmentation studies.
Hospital admittance in early labor increases the likelihood of cesarean delivery.
The little data we have specifically on VBAC labors finds a marked increase in cesarean delivery with admittance in early labor. One study reported a 25% cesarean rate in the 130 women admitted at less than 4 cm dilation versus 10% in the 72 women admitted at 4 cm dilation or more.18 Another, in 52 women, reported a 62% cesarean rate with admission at less than 4 cm dilation versus 28% in women admitted at 4 cm dilation or more.20
Looking at labors in general in women with prior births, studies consistently find a small increase in cesareans in the early admittance group.5, 18, 20, 22 Cesarean rates in the early admittance group ranged from 2% to 5% while rates in the late admittance group ranged from 1% to 2% and the differences between them ranged from 2 to 3 more per 100.
Looking at 1st-time mothers because VBAC labors are likely to progress more like first labors than labors in women with only prior vaginal births, the gap is much wider. Cesarean rates with early labor admittance ranged from 10% to 22% versus 3% to 10% with admittance in more active labor, and differences ranged from 3 to 18 more women per 100.5, 10, 18, 20-22, 32-34, 41 Even more to the point, studies report more cesareans for progress delay: 4 to 8 more per 100 with early admission.19, 33, 34
One possible explanation is that women experiencing dysfunctional labors are more likely to present at the hospital earlier in labor, but observations argue against this. One study found that sending women in early labor home decreased their cesarean rate compared with women who were admitted immediately (Holmes 2001). Another noted that over the three-year course of the study, the percentage of later admissions rose from 54% to 68%.22 If women with dysfunctional labors were simply being pushed to later admittance, you would expect that the cesarean rate with late admission would have risen, but it didn’t. Furthermore, studies report half or more of 1st-time mothers being admitted in early labor.5, 10, 18-22, 24, 32-34, 41 It is highly unlikely that such high proportions of women would be experiencing problematic labors. Much more likely is that doctors’ expectations that labor should be progressing faster than it usually does in early labor starts women on the downward spiral to a cesarean.
Preset time limits for making progress offers no advantages and increases cesarean and instrumental vaginal deliveries.
The idea that newborn outcomes will be better and cesareans will be reduced if labor duration isn’t allowed to exceed preset time limits is enshrined in labor graphing with its “alert” and “action” lines and time limits on pushing; however the evidence doesn’t support the theory.
A systematic review (a study of studies on a particular topic) found no decrease in oxytocin administration to strengthen contractions or cesarean delivery and no improvement in newborn condition at birth with labor graph use compared with no labor graph use.28 It also found that more stringent guidelines increased the use of augmentation, cesarean, or both without improving outcomes.
As for second stage (the time between full dilation and the birth of the baby), studies consistently find that most women with second stages exceeding definitions of normal duration will birth vaginally8, 13, 14, 16, 27 and that cesarean rates jump for women exceeding versus not exceeding the threshold for prolonged second stage.36 A hard and fast “time’s up” subjects large numbers of women to cesarean surgery unnecessarily.
Instrumental delivery rates leap upward too in women defined as having prolonged second stage as do, not surprisingly, anal tear rates—at least in a U.S. study where midline episiotomy (a cut straight down toward the anus) would be the norm.3, 8, 13, 16 You could argue that the increase in instrumental deliveries would be expected, except that one study looked at varying thresholds for “prolonged second stage” and found that the leaps were similar regardless of the definition of prolonged.8 Instrumental delivery rates were 12-17% for “not prolonged” using any of the three progressively lengthening definitions versus 31-38% for labors deemed “prolonged.” Likewise, anal injury rates ranged from 7-9% for “not prolonged” to 15-17% with “prolonged” second stage.
It is true that studies find an increase in adverse maternal or newborn outcomes correlating with second-stage duration,2-4, 8, 15, 16, 27, 36, 37, 39 but likelihood depends on when doctors decide to deliver the baby. Giving women more time decreases instrumental and cesarean deliveries and therefore the increased adverse outcomes associated with them.3, 8, 13, 14, 16, 36 Finally, serious newborn adverse outcomes are uncommon and the absolute increase with longer duration is small.8, 15, 16, 27, 37
Planned out-of-hospital VBAC appears to increase perinatal mortality.
Two studies report on deaths during labor and in the days after delivery in sizeable populations eligible for out-of-hospital birth at labor onset.
The first is of women at freestanding (not inside a hospital), birth centers.29 The overall perinatal mortality rate was 48 per 10,000 (7/1453). Two deaths were associated with the scar giving way in labor, which calculates to a scar-related perinatal mortality rate of 14 per 10,000. Among the remaining five, three were unrelated to having a prior cesarean. One had to do with a true knot in the umbilical cord and another with a breech baby with a prolapsed umbilical cord. Both these women were transferred to hospital immediately on arrival at the birth center. The third case resulted from stuck shoulders at delivery (shoulder dystocia). Among the final two, one was a probable placental detachment (placental abruption), and the last was a baby who developed a severely abnormal fetal heart rate. Among the 1271 women who neither exceeded 42 weeks gestation nor had more than 1 cesarean, the scar rupture rate was 20 per 10,000 as was the overall perinatal mortality rate.
The other study reports on home VBACs with a certified midwife.9 The overall perinatal mortality rate was 48 per 10,000 (5/1052). Two of these were probably related to the scar giving way for a scar-related perinatal mortality rate of 19 per 10,000; the other three were not, having to do with delivery of twins, a breech baby, and an umbilical cord prolapse.
These perinatal mortality rates compare unfavorably to rates in hospital VBAC labors. For example, a large, multicenter study reported a perinatal mortality rate of 9 per 10,000 in 15,323 VBAC labors, and the rate was even lower (5 per 10,000) in the 17,714 elective repeat cesareans.38