Mediolateral episiotomy reduces the risk for anal sphincter injury during operative vaginal delivery.

OBJECTIVE: To determine the risk factors for anal sphincter injuries during operative vaginal delivery. SETTING AND DESIGN: A population-based observational study. POPULATION: All 21 254 women delivered with vacuum extraction and 7478 women delivered with forceps, derived from the previously validated Dutch National Obstetric Database from the years 1994 to 1995. METHODS: Anal sphincter injury was defined as any injury, partial or complete, of the anal sphincters. Risk factors were determined with multivariate logistic regression analysis. MAIN OUTCOME MEASURES: Individual obstetric factors, e.g. fetal birthweights, duration of second stage, etc. RESULTS: Anal sphincter injury occurred in 3.0% of vacuum extractions and in 4.7% of forceps deliveries. Primiparity, occipitoposterior position and fetal birthweight were associated with an increased risk for anal sphincter injury in both types of operative vaginal delivery, whereas duration of second stage was associated with an increased risk only in vacuum extractions. Mediolateral episiotomy protected significantly for anal sphincter damage in both vacuum extraction (OR 0.11, 95% CI 0.09-0.13) and forceps delivery (OR 0.08, 95% CI 0.07-0.11). The number of mediolateral episiotomies needed to prevent one sphincter injury in vacuum extractions was 12, whereas 5 mediolateral episiotomies could prevent one sphincter injury in forceps deliveries. CONCLUSIONS: Primiparity and occipitoposterior presentation are strong risk factors for the occurrence of anal sphincter injury during operative vaginal delivery. The highly significant protective effect of mediolateral episiotomies in both types of operative vaginal delivery warrants the conclusions that this type of episiotomy should be used routinely during these interventions to protect the anal sphincters.

Effects of diazoxide on maternal and fetal circulations in normotensive and hypertensive pregnant sheep.

Diazoxide is a potent antihypertensive agent due to its peripheral vasodilator action. For this reason it is used in the management of hypertensive crises in pregnancy. To assess the effects of an intravenous bolus injection of diazoxide on maternal and fetal hemodynamics an experimental study was performed in 11 chronically instrumented pregnant sheep. In six ewes hypertension was induced by surgical removal of one kidney and reduction of arterial blood flow to the remaining kidney (one-kidney renovascular hypertension). The other five ewes remained normotensive. In a second operation, one week after the first one, the animals were equipped with electromagnetic flow transducers and catheters for monitoring of blood flow in a renal, a uterine, and an umbilical artery and for measurement of maternal and fetal arterial blood pressures, and blood sampling. Maternal heart rate was derived from the arterial pressure curve, fetal heart rate from a fetal ECG. Experiments were begun on the third day after the second operation. In each experiment a bolus of 300 mg of diazoxide was administered intravenously, with or without rapid simultaneous infusion of 500 ml of a plasma expander. A total of 17 experiments were performed in the one-kidney hypertensive ewes (Group H), nine with and eight without plasma expander. In the five normotensive animals (Group NH) 10 experiments were done, four with and six without plasma expansion. During the control periods maternal arterial pressure was approximately 30 mm Hg higher in Group H than in Group NH. In Group H also maternal heart rate, and renal and uterine vascular resistances were significantly elevated. All fetal variables were equal in both groups. Administration of diazoxide without simultaneous plasma expansion resulted in both groups in a significant fall in maternal arterial pressure, a rise in maternal heart rate, and a fall in uterine and renal blood flows with a rise in vascular resistance. Fetal arterial pressure and umbilical blood flow showed no significant changes, but fetal heart rate showed a transient fall together with a drop in fetal pO2 and pH, although acidosis did not occur. When diazoxide was combined with a plasma expander maternal blood pressure did not change significantly in Group NH, but fell in Group H. Maternal heart rate rose significantly in both groups. The decrease in uterine and renal blood flows which occurred when diazoxide was given without plasma expansion was not observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Unstable glycosylated hemoglobin in patients with diabetes mellitus.

Incubation of washed erythrocytes for 4 h at 37 degrees C in saline resulted in the disappearance of an unstable glycosylated fraction. In a reference group, its amount was very small, but its presence had a significant influence on the upper level of the reference range. In non-diabetic pregnant women, the unstable fraction was significantly higher than in the non-pregnant individuals, which resulted in a lower reference range for the stable HbA1. In diabetic patients, the average unstable HbA1 was about 10% of the "unincubated" level, with marked differences between individuals (0--30%), even in patients with a slightly elevated HbA1. Therefore it is important to determine the concentration of stable HbA1.