William F. O'Brien

Peritoneal closure or non-closure at cesarean

The value of peritoneal closure at the time of cesarean birth was evaluated prospectively. Two hundred forty-eight women undergoing low transverse cesarean through a Pfannenstiel skin incision were assigned to one of two groups: peritoneum open (N=127) or peritoneum closed (N=121). The mean (± SEM) surgical time in the open group (48.1 ± 1.2 minutes) was significantly less than for the closed group (53.2 ± 1.4 minutes) (P<.005). There were no postoperative differences between the groups in the incidence of wound infection, dehiscence, endometritis, ileus, and length of hospital stay. Our study suggests that leaving the parietal peritoneum unsutured is an acceptable way to manage patients at cesarean delivery.

A randomized study of antibiotic therapy in idiopathic preterm labor.

&NA; A randomized study was undertaken to test the effects of antibiotics as an adjunct to established methods of tocolysis. One hundred fifty patients with cervical dilation of 1 cm or more and no clinically identifiable cause for preterm labor qualified for the study. Fifty‐three (35%) received 500 mg ampicillin orally every 6 hours, 50 (33%) received 500 mg erythromycin orally every 6 hours, and 47 served as controls. Antibiotics were prescribed for 10 days, and the treatment was not altered by the results of cervical cultures. Of these 150 patients, 16 (11%) had positive amniotic fluid cultures. The pregnancies with positive amniotic fluid culture were characterized by significantly less time gained after admission (2.6 versus 28.7 days) and lower birth weight (1262 versus 2470 g) than in those with negative cultures. Histologic studies of the placenta revealed chorioamnionitis in 22 (16%) of 134 patients with negative amniotic fluid cultures; these pregnancies were associated with less time gained after admission (12.5 versus 31.9 days) and lower birth weight (1680 versus 2618 g) compared with pregnancies without histologic chorioamnionitis. In patients with similar gestational age and cervical dilation, the adjunctive use of antibiotic therapy resulted in a statistically significant delay from admission to delivery (30 versus 17 days). In cases of negative amniotic fluid cultures, cervical colonization with group B streptococcus and/or Gardnerella vaginalis increased the risk of prematurity, which improved significantly when ampicillin was given.

Prevention of anticardiolipin antibody-related pregnancy losses with prednisone and aspirin

Abstract purpose: Prevention and treatment of pregnancy loss associated with the antiphospholipid syndrome (APS) are controversial. Successful pregnancies have been reported with prednisone and low-dose aspirin in patients with lupus anticoagulant and anticardiolipin antibodies (aCL), but failure has also been reported. The purpose of this prospective study was to define the efficacy of such combination therapy in the prevention of pregnancy loss related to aCL. patients and methods: Consecutive pregnant patients with a minimum of one pregnancy loss and at least two positive aCL determinations more than 3 months apart, and in whom other causes of pregnancy loss were ruled out, were included in the study. aCL concentrations were determined by enzyme-linked immunosorbent assay before and during therapy. Patients received prednisone, at a dosage of 40 mg/d, for 4 weeks. The dose was then tapered down 10 mg every 4 weeks, and then to a maintenance dose of 5 mg/d. They also received aspirin, 81 mg/d, throughout the pregnancy. Babies were evaluated during the pregnancy by measurement of fetal heart rate and ultrasonography, and after the delivery by measurement of weight and Apgar scores, and, in some cases, by arterial gasometry. results: Eleven patients with a mean (± SD) age of 33.2 ± 5.01 years were included. Prior to therapy, the rate of live-born babies was 15.6% (32 previous fetal losses and 5 live-born babies), and, after therapy, it was 100% (12 pregnancies and 12 live-born babies). There were no significant adverse effects to either mothers or babies. All the patients had positive aCL determinations. Nine patients had positive IgG aCL. The levels of the antibodies decreased during treatment in these nine patients. IgM aCL determinations were positive in nine patients. The levels of this isotype decreased in eight patients (90%) during treatment. conclusions: Treatment with prednisone and aspirin appears to be efficacious, safe, and economic in the prevention of pregnancy loss and fetal growth retardation in patients with aCL.

Potential role of endothelin-1 in normal and hypertensive pregnancies

Endothelins are the most potent naturally occurring vasoconstrictors yet discovered. Both normal and abnormal pregnancies are associated with significant changes in vascular smooth muscle; therefore the potential role of endothelin in pregnancy was investigated. Plasma immunoreactive endothelin-1 concentration was measured by radioimmunoassay in blood from women with normal pregnancy and preeclampsia and in cord blood from normal pregnancies. Endothelin-1 levels were elevated in pregnant women during labor when compared with levels in nonpregnant women and patients with normal pregnancies before labor. Preeclampsia in nonlaboring women before treatment was associated with higher endothelin values when compared with values in normal nonlaboring patients and women with preeclampsia after magnesium sulfate infusion. The umbilical venous concentration of endothelin was 10 times higher than normal pregnant levels and four times higher than levels in laboring patients.

The expression of cyclooxygenase-2 (COX-2) in amnion and decidua following spontaneous labor.

OBJECTIVE Prostaglandins production rises dramatically during term and preterm labor. The source of this production is thought to be the fetal membranes and maternal decidua. The enzyme responsible for the conversion of arachidonic acid to the prostaglandins and related endoperoxides is variously known as prostaglandin synthase or cyclooxygenase (COX). An inducible form of this enzyme, COX-2, has been described in several tissues. The purpose of this study was to investigate a possible role for COX-2 in labor by comparing the COX-2 content in amnion and decidua from laboring and non-laboring patients. STUDY DESIGN Fetal membranes from seven normal labor and ten elective cesarean sections at term were collected immediately following delivery. The maternal age and gravity were similar between the groups. The amnion and decidua were identified, washed in sterile saline, frozen in liquid nitrogen and stored in -70 degrees C. COX-2 expression was determined using Western Blot analysis with a purified COX-2 antibody. A scanning densitometer was used to quantify the bands. Results were expressed as mean +/-S.D. ng/50 micrograms protein. RESULTS The concentration of COX-2 in amnion of laboring women showed a twofold increase (240.0 +/- 17.6 vs. 120.7 +/- 5.1) compared to the non-labored group (p < 0.05). The concentration in the decidua showed no significant increase during labor (38.1 +/- 7.5 vs. 26.4 +/- 2.1, p > 0.05). CONCLUSION We evaluated the role of COX-2 in normal labor. Our study demonstrates that COX-2 is significantly induced in the amnion following spontaneous labor. These findings suggest that the induction of amnion COX-2 may be involved in the process of human labor.

Blunt versus sharp expansion of the uterine incision in low-segment transverse cesarean section

OBJECTIVE Both blunt and sharp expansion of the initial incision at transverse cervical cesarean birth have advocates, on the basis of theoretic concerns. We sought to study the incidence of complications, including unintended extension, associated with each of these methods by comparison by means of a prospective, randomized study. STUDY DESIGN Women scheduled to undergo nonemergency cesarean birth were assigned to blunt and sharp expansion groups. Other than expansion of the incision, standard technique was used throughout surgery. Data, including length and number of unintended extensions, vessel laceration, and length of surgery, were recorded immediately. RESULTS The blunt (n = 139) and sharp (n = 147) expansion groups were similar with regard to indication and duration of labor. No difference in the incidence of unintended extension, postoperative endometritis, duration of surgery, or estimated blood loss was noted. The frequency of unintended extension (1.4%, 15.5%, and 35.0% for no labor and first and second stages, respectively) correlated with the stage of labor. CONCLUSION Blunt and sharp expansions of the uterine incision are equivalent in ease and safety.

The value of the cervical score in predicting successful outcome of labor induction

Objective To compare cervical dilation and the Bishop score as correlates of successful labor induction and vaginal delivery and to determine whether the prognosis of postripening cervical characteristics varies with the method of ripening used. Methods Four hundred forty-three women with Bishop scores less than 9 who required induction of labor were assigned randomly to cervical ripening with prostaglandin E2 gel or hygroscopic dilation. The Bishop score and its component characteristics were evaluated as univariate correlates of successful induction of labor and vaginal delivery and then were assessed using logistic regression to adjust for other maternal and fetal factors. The differences in the association between method of ripening and successful labor induction were evaluated relative to pre-ripening and post-ripening cervical examination characteristics. Results Cervical dilation was a better correlate of successful labor induction and vaginal delivery than was the Bishop score, even after exclusion of patients with initial Bishop scores greater than 6 and dilation greater than 3.0. Both ripening methods yielded similar success in labor induction and vaginal delivery, but when categorized by post-ripening cervical examinations, patients undergoing hygroscopic ripening had lower rates of successful labor induction and vaginal delivery. Conclusion Cervical dilation is a better predictor of successful labor induction and vaginal delivery than either the Bishop score or any other Bishop score component characteristic. The likelihood of successful labor induction and vaginal delivery based on post-ripening cervical characteristics varies by the ripening method used.

Alterations in platelet concentration and aggregation in normal pregnancy and preeclampsia

Platelets were evaluated in normal pregnant women and in pregnant subjects with mild and severe preeclampsia, nonpregnant control subjects, and pregnant subjects with chronic hypertension. The parameters studied included platelet count, presence of circulating platelet aggregates, and in vitro platelet aggregability by means of a variety of agonists of platelet aggregation. When subjects with a normal pregnancy were compared to nonpregnant controls, they demonstrated a significantly lower platelet count and an increase in circulating platelet aggregates and in vitro hypoaggregability. Significant differences among the groups of pregnant subjects could not be found. These studies suggest the occurrence of platelet activation in pregnancy. This activation causes in vivo platelet aggregation followed by exhaustion of platelets.

The induction of cyclooxygenase-2 (COX-2) in intact human amnion tissue by interleukin-4

Infection is a major cause of preterm labor. Amniotic fluid from women in preterm labor associated with intrauterine infection contains increased concentrations of cytokines. The mechanism underlying this association may be a cytokine-mediated stimulation of amnion cell prostaglandin production. The biosynthesis of prostaglandins from arachidonic acid is regulated by the enzyme cyclooxygenase which exists in two forms; the constitutive form (COX-1) and the other mitogen inducible (COX-2). The purpose of this study was to evaluate the effect of the cytokine interleukin-4 (IL-4) on cyclooxygenase activity and PGE2 production in amnion. Amnion tissue was taken at caesarean section from term women not in labor and immediately incubated for 2 hours in media containing concentrations of IL-4 ranging from 1 to 100 ng/ml. An increase in both COX-2 enzyme and prostaglandin E2 (PGE2) production was observed for all concentrations of IL-4 greater than 25 ng/ml (P < 0.05, n = 8). No change in COX-1 was observed. Our data suggest that the cytokine IL-4 may be involved in the pathogenesis of premature labor by inducing COX-2 in amnion tissue resulting in increased production of PGE2 and subsequent myometrial activity.

The effect of magnesium sulfate on bleeding time in pregnancy.

OBJECTIVE The bleeding time is one of the most commonly used diagnostic tests to evaluate platelet-related hemorrhagic disorders. Magnesium has been shown in vitro to be a platelet antiaggregant. This study was conducted to evaluate the hypothesis that magnesium sulfate has no effect on the template bleeding time. STUDY DESIGN The study group consisted of 24 women who required magnesium sulfate in pregnancy. A blood cell count, platelet count, magnesium level, bleeding time, and mean arterial pressure were obtained before and 2 hours after magnesium sulfate infusion. Magnesium sulfate was infused beginning with a 6 gm intravenous bolus followed by 2 gm/hr. A template bleeding time was performed with a Simplate-II (Organon Teknika, Durham, N.C.) device. Two of the authors performed all the bleeding times. Data were analyzed with a paired t test and Wilcoxon rank test. RESULTS Fifteen (63%) patients received magnesium sulfate for tocolysis or before external cephalic version and nine (37%) for preeclampsia prophylaxis. No differences were found between the normotensive and hypertensive groups regarding maternal age, gestational age, initial bleeding time, or platelet count. Analysis of the entire study group revealed a prolongation of the bleeding time after magnesium sulfate (5.7 +/- 1.8 vs 6.6 +/- 1.9 minutes, p < 0.05); a lowering of the mean arterial pressure (p < 0.05), and a rise in the magnesium level (p < 0.05). Four patients (16.7%) had a postmagnesium bleeding time > 9 minutes. CONCLUSION Magnesium sulfate appears to prolong the bleeding time in pregnancy. The clinical significance remains to be determined.