Robert A. Kinch

The Role of Uterine Closure in the Risk of Uterine Rupture

To the Editor: I read with great interest the latest article on the role of single compared with double stitching on uterine closure.1 The article found that one of the 10 centers had no uterine ruptures during the 10year period. Perhaps future protocol might profit by looking at their apparently successful management. The study included 96 uterine ruptures after previous cesarean delivery, but only 74 of them had a known method of closure on the previous cesarean delivery, the variable being studied in this report. The 23% of cases in which the previous method of closure was unknown were irrelevant to the study. Despite this fact, these cases were found “matching controls” that occurred at the same time and place as the unknown closure cases, and the controls of the unknown cases were considered in all the analyses. This may reflect a desire to “prove” a predetermined outcome. In the study, to calculate how many controls were needed, it was assumed that 50% of uterine rupture would happen in women who had previous single-suture technique, whereas only 25% of controls would have previous singlesuture closure. Is it serendipitous that that the conclusions match the predetermined assumptions? It is exceeding logic that the more you stretch the skin near scar tissue, the more likely it is to rupture. Eight large studies found that trials of labor when the birth weight was more than 4,000 g was a significant factor for vaginal birth after cesarean failure and uterine rupture, and one found low rates of uterine rupture with birth weights of 2,500 g or less.2–10 Case–control studies are reliable when variables with important influence are matched for in the controls. Because birth weight is an already known and important factor for uterine rupture, birth weights needed to be matched in the control group with the cases. The authors write that it is impossible to control birth weight, thereby emphasizing a need to determine which closure rate is more effective. The literature already has shown that low glycemic diets with 50 g of protein intake per day after 12 weeks of gestation result in lower birth weights without increases in stillbirth or prematurity.11 A prospective multicenter study, controlling for the important factor of birth weight, surely is required before this question can be resolved.

Anxiety, pregnancy, labor, and the neonate

Abstract In order to study the relationship between maternal anxiety during pregnancy and birth weight, a prospective study involving 61 pregnant women was undertaken. At the same time, provision was made for the testing of several other hypotheses, among them that anxiety during pregnancy would be negatively correlated with age, gravidity, and parity and that those mothers who had an abnormal labor had been more anxious during their pregnancy than those whose labors were normal. In all cases anxiety was measured objectively by means of two anxiety scales of the “true or false” type. Although the results did not support the postulated relationship between anxiety and birth weight, several of the other hypotheses postulated proved to be statistically significant.

Recent trends in caesarean delivery rates and indications for caesarean delivery in Canada.

OBJECTIVE To examine recent trends in Caesarean delivery rates as well as the indications for Caesarean delivery in Canada, excluding the provinces of Manitoba and Quebec. METHODS All deliveries (N = 1 807 388) recorded in the Canadian Institute for Health Informations Discharge Abstract Database for the years 1994/95 to 2000/01 were included in the study (all hospital deliveries in Canada except for those occurring in Manitoba and Quebec). Temporal trends and inter-provincial/territorial variations in Caesarean delivery rates were quantified, and the primary indications for Caesarean delivery during the study period were compared. RESULTS The overall Caesarean delivery rate increased from 18.0% in 1994/95 to 22.1% in 2000/01. The primary Caesarean delivery rate increased from 12.7% to 16.3%, while the rate of vaginal birth after Caesarean decreased from 33.3% to 28.5% over the same period. Most of the increase in primary Caesarean deliveries was due to increases in Caesarean deliveries for dystocia, which increased from 6.9% in 1994/95 to 9.2% in 2000/01. The largest increase in repeat Caesarean deliveries was due to elective repeat Caesarean sections, which increased from 37.7% to 40.3%. Approximately 15% of the increase in overall Caesarean delivery rates was explained by increases in maternal age. The rate of vaginal deliveries following forceps rotation declined from 1.9% in 1994/95 to 1.3% in 2000/01. CONCLUSION Most of the recent increase in Caesarean delivery rates in Canada was attributed to increases in primary Caesarean delivery for dystocia and elective repeat Caesarean deliveries.

Effect of intravenous clonidine on menopausal flushing and luteinizing hormone secretion

Summary. The effect of clonidine (0.075 mg given intravenously) on subjectively experienced menopausal flushes, skin temperature and luteinizing hormone (LH) secretion was investigated in eight women in a double‐blind, saline‐controlled cross over study. Subjects were monitored over a 5‐hour period. The number and magnitude of temperature peaks (increment >1°C) was unaffected by clonidine. Clonidine significantly decreased the number of subjectively experienced flushes as well as the intensity of the flushes. Clonidine had no effect on the number of LH secretory pulses or on total LH secretion. These results indicate that the therapeutic effect of clonidine is independent of factors responsible for episodic skin temperature changes or factors regulating LH secretion.

Fetoscopy and fetal blood sampling: A percutaneous approach☆☆☆

Abstract A technique of fetoscopy is described which is performed percutaneously under local anesthesia. A cannula has been developed that allows the sampling of fetal blood. Direct visualization of the fetus and further sampling of its environment now seem possible but must await extensive study of safety prior to clinical use.

Premature Ovarian Failure

Premature ovarian failure remains a multifactorial syndrome in which genetic, immune, and environmental factors may play a role. The possible etiology and pathophysiology of premature ovarian failure is reviewed. A scheme of the management of premature ovarian failure is illustrated. This allows a logical approach in which the final diagnosis has to be made with laparotomy ovarian biopsy. It is hoped that future research can be directed to the solution of the etiology of premature menopause and insensitive ovary syndrome, as well as the management of patients with insensitive ovary syndrome, so that either by estrogen replacement or stimulation with hypothalamic/pituitary hormone these primordial follicles can be induced to develop normally.

Effect of naloxone on menopausal flushes, skin temperature, and luteinizing hormone secretion

The effect of naloxone (1.4 mg/hr for 3 hours) on subjectively experienced menopausal flushes, skin temperature, and luteinizing hormone secretion was investigated in seven women in a double-blind, saline-controlled, crossover study. Naloxone had no effect on the number of subjective flushes, episodic skin temperature elevation, luteinizing hormone pulses, variability of luteinizing hormone secretion, or total luteinizing hormone secretion. This study suggests that a naloxone-sensitive opioid mechanism is not active in modulating luteinizing hormone secretion in the postmenopausal woman and that opioid receptor blockade is not effective in altering the frequency of menopausal flushes.

Comparison of obstetric outcomes between on-call and patients' own obstetricians

Background: The question “will you be delivering my baby?” is one that pregnant women frequently ask their physicians. We sought to determine whether obstetric outcomes differed between women whose babies were delivered by their own obstetrician (regular-care obstetrician) and those attended by an on-call obstetrician who did not provide antenatal care. Methods: We performed a cohort study of all live singleton term births between 1991 and 2001 at the Royal Victoria Hospital in Montréal. We excluded breech deliveries, elective cesarean sections and deliveries with placenta previa or prolapse of the umbilical cord. Logistic regression analysis was used to compare obstetric outcomes (e.g., cesarean delivery, instrumental vaginal delivery and episiotomy) between the regular-care and on-call obstetricians after adjustment for potential confounders. Results: A total of 28 332 eligible deliveries were attended by 26 obstetricians: 21 779 (76.9%) by the patients own obstetrician and 6553 (23.1%) by the on-call obstetrician. Compared with women attended by their regular-care obstetrician, those attended by an on-call obstetrician had higher rates of cesarean delivery (11.9% v. 11.4%, adjusted odds ratio [OR] 1.13, 95% confidence interval [CI] 1.03–1.24, p < 0.01) and of third-or fourth-degree tears (7.9% v. 6.4%, adjusted OR 1.21, 95% CI 1.07–1.36, p < 0.01) but lower rates of episiotomy (38.5% v. 42.9%, OR 0.77, 95% CI 0.72–0.82, p < 0.001). No differences were observed between the groups in the rate of instrumental vaginal delivery. The increase in the overall rate of cesarean delivery among women attended by an on-call obstetrician was due mainly to an increase in cesarean deliveries during the first stage of labour because of nonreassuring fetal heart tracing (2.9% v. 1.7%, adjusted OR 1.79, 95% CI 1.49–2.15, p < 0.001). The time of day of delivery did not modify the observed effects. Interpretation: The type of attending obstetrician (regular care v. on call) had a minor effect on obstetric outcomes.

Evaluating the role of bedrest on the prevention of hypertensive diseases of pregnancy and growth restriction.

Background. Evaluating the effect of restricted activity on the development of preeclampsia under experimental clinical settings has been compromised by inherent selection bias and differential misclassification. The aim of our study was to overcome such limitations by using hospitalized bedrest for preterm labor/birth-related indications as an unbiased measure of restricted activity and evaluate its effect on the development of hypertensive diseases of pregnancy. Methods. We conducted a retrospective cohort study using data from the McGill Obstetrical and Neonatal Database on all pregnancies that took place between 1991 and 2001. We defined “exposure” as hospitalized bed rest for preterm labor/birth related indications and used unconditional logistic regression models to estimate its adjusted effect on the development of hypertensive diseases of pregnancy. Results. Data were available on 36,140 pregnancies. 677 women were hospitalized and prescribed bedrest for either preterm contractions (71%), preterm premature rupture of membranes (18%), an incompetent cervix (8%), or other indications. Among all women, bedrest was associated with a significant reduced risk for developing preeclampsia, 0.27 (0.16–0.48). In a stratified analysis, women delivering prior to 34 weeks of gestation had an even more pronounced reduced risk for developing preeclampsia 0.12 (0.03–0.50) as well as a reduced risk for developing intrauterine growth restriction 0.38 (0.18–0.84). Conclusion. When strictly adhered to, bedrest may be an effective measure in the prevention of preeclampsia and early intrauterine growth restriction.

Effect of guanfacine, an alpha-adrenergic agonist, on menopausal flushing

The effect of guanfacine (0.5 mg/day), an alpha-adrenergic agonist, on menopausal flushing, was studied in a double-blind, placebo-controlled crossover study in 11 patients. Both guanfacine and placebo significantly decreased the total number of flushes from baseline values. There was, however, no significant difference between placebo and guanfacine. Larger doses of guanfacine may be required to exert a therapeutic effect similar to that reported in the literature with the alpha-adrenergic agents, clonidine and alpha-methyldopa.