[Is CV measurement relevant for the verdict "vaginal delivery prohibited"?]

The clinical significance of conjugata vera (CV) values for estimating the possibility of vaginal delivery when caesarean section (CS) has earlier been performed is uncertain and therefore the prognostic value of this parameter was examined.

We reviewed retrospectively the case notes of women who had had a CS or a vaginal delivery after a previous CS at the Department of Obstetrics and Gynaecology, County Hospital in Herlev, in 1998. For comparison of the results and statistical analysis, probability values (P) were calculated by logistic regression analysis.

The study comprised 246 women, whose CV was measured during the current or a previously performed CS. The probability of an emergency CS in the 106 women with a history of CS showed a clear decline with increasing CV values, (p = 0.006). No obvious difference was found in the distribution of CV values in the 179 women with CS deliveries in 1998, when we compared the indications, "asphyxia" and "others", but it was significantly lower for the indication, "cephalopelvic disproportion" (p = 0.001). Taking into account the CV values, no association was evident between the birth weight, the height of the mother, or the CS probabilities.

Our study demonstrated that CV values are considerably predictive of repeated CS; women with CV values < or = 11 cm have a probability of more than 50% for repeated CS and with CV values < or = 10 cm the probability rises to two thirds.

CV measurement has value as a parameter in itself and can help the obstetrician to estimate the route of delivery at subsequent births. There is an obvious correlation between low CV values and the probability of CS with "cephalopelvic disproportion" as the indication.