5 posts tagged “statistics”

Safety and Efficacy of Vaginal Birth After Cesarean Attempts at or Beyond 40 Weeks of Gestation (Obstetrics and Gynecology, 2005;106:700-706)

Summary: Women attempting VBAC before or at 40 weeks gestation had higher success rates (77.8%) than women past 40 weeks gestation (68.7%). Uterine rupture rates between the two groups were similar. So, VBAC after EDD (estimated due date) is just as safe as before or at EDD, though odds of success are lower.

I can't access the full text, just the abstract, so I'm wondering why the success rates differ between "at term" women and "post-dates" women. My guess is that it has nothing to do with the length of gestation but rather with how a woman's labor and delivery is managed differently once she reaches 40 weeks. Just a guess.

Outcomes of planned home births versus planned hospital births after regulation of midwifery in British Columbia -- no increased risk to mother or baby from home births compared to hospital births, but home births had significantly fewer interventions.

Outcome of planned home and planned hospital births in low risk pregnancies: prospective study in midwifery practices in the Netherlands -- Conclusions: The outcome of planned home births is at least as good as that of planned hospital births in women at low risk receiving midwifery care in the Netherlands. This is great, except that the Netherlands has a completely different philosophy surrounding birth than the United States. Midwifery and home births are standard choices and comprise much higher percentages of birth than in the U.S. So kind of comparing apples to oranges, but still significant, because it shows that midwifery as the standard model of care is just as good, if not better, for most women than the standard OB care common in the U.S.

American College of Nurse-Midwives Position Statement on Home Birth (December 2005)

In short, low-risk home births had outcomes quite similar to low-risk hospital births, in terms of safety. The big difference is the rate of medical interventions: women giving birth in hospitals had much higher rates of episiotomy, forceps/vacuum delivery, and cesarean surgeries than women who planned home births.

So, midwives attending home births achieved the same safety rates as doctors and midwives attending hospital births, but without all the interventions.

Outcomes of planned home births with certified professional midwives: large prospective study in North America

Objective To evaluate the safety of home births in North America involving direct entry midwives, in jurisdictions where the practice is not well integrated into the healthcare system.

Setting All home births involving certified professional midwives across the United States (98% of cohort) and Canada, 2000.

Participants All 5418 women expecting to deliver in 2000 supported by midwives with a common certification and who planned to deliver at home when labour began.

Main outcome measures Intrapartum and neonatal mortality, perinatal transfer to hospital care, medical intervention during labour, breast feeding, and maternal satisfaction.

Results 655 (12.1%) women who intended to deliver at home when labour began were transferred to hospital. Medical intervention rates included epidural (4.7%), episiotomy (2.1%), forceps (1.0%), vacuum extraction (0.6%), and caesarean section (3.7%); these rates were substantially lower than for low risk US women having hospital births. The intrapartum and neonatal mortality among women considered at low risk at start of labour, excluding deaths concerning life threatening congenital anomalies, was 1.7 deaths per 1000 planned home births, similar to risks in other studies of low risk home and hospital births in North America. No mothers died. No discrepancies were found for perinatal outcomes independently validated.

Conclusions Planned home birth for low risk women in North America using certified professional midwives was associated with lower rates of medical intervention but similar intrapartum and neonatal mortality to that of low risk hospital births in the United States.

Contrast this study with the one below.

In short, mothers with multiple VBACs have increasingly lower levels of complications while mothers with multiple elective Cesareans with no labor have increasingly higher levels of complications.

Obstetrics & Gynecology (2006;107:1226-1232)

OBJECTIVE: To estimate the magnitude of increased maternal morbidity associated with increasing number of cesarean deliveries.

METHODS: Prospective observational cohort of 30,132 women who had cesarean delivery without labor in 19 academic centers over 4 years (1999–2002).

RESULTS: There were 6,201 first (primary), 15,808 second, 6,324 third, 1,452 fourth, 258 fifth, and 89 sixth or more cesarean deliveries. The risks of placenta accreta, cystotomy, bowel injury, ureteral injury, and ileus, the need for postoperative ventilation, intensive care unit admission, hysterectomy, and blood transfusion requiring 4 or more units, and the duration of operative time and hospital stay significantly increased with increasing number of cesarean deliveries. Placenta accreta was present in 15 (0.24%), 49 (0.31%), 36 (0.57%), 31 (2.13%), 6 (2.33%), and 6 (6.74%) women undergoing their first, second, third, fourth, fifth, and sixth or more cesarean deliveries, respectively. Hysterectomy was required in 40 (0.65%) first, 67 (0.42%) second, 57 (0.90%) third, 35 (2.41%) fourth, 9 (3.49%) fifth, and 8 (8.99%) sixth or more cesarean deliveries. In the 723 women with previa, the risk for placenta accreta was 3%, 11%, 40%, 61%, and 67% for first, second, third, fourth, and fifth or more repeat cesarean deliveries, respectively.

CONCLUSION: Because serious maternal morbidity increases progressively with increasing number of cesarean deliveries, the number of intended pregnancies should be considered during counseling regarding elective repeat cesarean operation versus a trial of labor and when debating the merits of elective primary cesarean delivery.

Straight from the horse's mouth!

Obstetrics & Gynecology (February 2008;111:285-291).

OBJECTIVE: To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs.

METHODS: From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery.

RESULTS: Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter.

CONCLUSION: Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy.

I feel it important to note that this study does not say that VBACs are always safer than C-sections. It simply reports that once a woman has had a successful VBAC, the likelihood of she having future successful VBACs increases.