Biomedical subjects

M E Boyd

Publications and source records attributed to M E Boyd.

At least 19 recordsLinked to original sources

PubMed1992

The changing pattern of fetal death, 1961-1988.

The aim of this study was to assess any changes in cause-specific fetal death rates in the nonreferred population of a tertiary care unit. The fetal death rate (per 1000 births) among 88,651 births diminished from 11.5 in the 1960s to 5.1 in the 1980s. Fetal death due to intrapartum asphyxia and Rh isoimmunization has almost disappeared. Toxemia and diabetes continue to make similar and small contributions to fetal death rates. There has been a significant decline in unexplained antepartum fetal deaths and in those caused by fetal growth retardation, but no significant change in the death rate due to intrauterine infection or abruptio placentae. During the 1960s, the risk of fetal death was increased in women with hypertension, diabetes, or a history of stillbirth; during the 1980s, only women with a history of insulin-dependent diabetes were at risk. Improved application of current knowledge may help decrease the fetal death rate caused by fetal growth retardation. Reduction in deaths due to abruptio placentae, intrauterine infections, or lethal malformations, as well as unexplained antepartum deaths, appears to depend on better understanding of the etiology of these disorders.

Cause of Death↗

PubMed1991

Postterm infants: too big or too small?

Concern over the postterm pregnancy has shifted from that of the difficult delivery of an excessively large fetus to the current concern with death in utero of an undernourished, small-for-date fetus. Studies of postterm pregnancy before the availability of ultrasonography may have included a large proportion of erroneous menstrual dates. The present study of 7000 infants was undertaken to reassess fetal growth in postterm pregnancies in which the expected date of confinement from last normal menstrual period dating was confirmed (+/- 7 days) by early ultrasonography. Results show a gradual shift toward higher birth weight and greater crown-heel length and head circumference between 273 and 300 days of gestational age. No evidence of postterm weight loss or lower weight for length could be demonstrated. Concern in postterm pregnancy should be for fetal macrosomia, not for intrauterine growth retardation.

Birth Weight↗

PubMed1989

Dilatation and curettage.

The most important role of dilatation and curettage is in the evacuation of retained products of conception; its diagnostic value is mostly limited to the detection of cancer of the endometrium. The procedure is associated with a number of complications, the majority of which occur during dilatation of the cervix. Vabra curettage is suggested as an alternative to diagnostic dilatation and curettage; it is efficient, is associated with fewer complications and is less expensive. Hysteroscopy is a useful supplement to Vabra curettage, especially in diagnosing focal lesions.

Biopsy↗

PubMed1989

Endometrial cancer.

Abdominal hysterectomy will cure cancer of the endometrium confined to the body of the uterus. If the tumour has spread beyond the uterus, adjuvant therapy will be needed. The likelihood of such spread can be predicted from postoperative histologic examination of the uterus or discovered by surgical staging. Surgical staging does not appear to be curative or to reduce the need for adjuvant therapy. Prognosis depends on the grade and location of the tumour in the uterus and the extent of invasion into the myometrium or beyond the uterus, and not on the removal of occult metastases.

Female↗

PubMed1989

Spontaneous abortion.

As a result of improved investigation and treatment techniques, understanding of all aspects of spontaneous abortion has improved. The term "threatened abortion" is often a misnomer, for the fate of the pregnancy is decided when bleeding occurs. A dilated cervix indicates that abortion is inevitable. If the cervix is not dilated, pelvic ultrasonography will usually show the following: a live fetus, an anembryonic pregnancy, incomplete abortion or missed abortion. If fetal heart movement is seen, no further treatment is needed and the prognosis is excellent (98% fetal survival). In other cases, the uterus must be evacuated, with a Karman catheter if the uterus is small, with a suction curette if the uterus is large. Forceful dilation of the cervix is avoided through the use of Laminaria.

Abortion, Septic↗

PubMed1988

The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations.

Despite recognition that estimation of gestational age (GA) based on maternal recollection of the last normal menstrual period (LNMP) is fraught with error, it is not generally appreciated that the magnitude and direction of this error vary as a function of the LNMP estimate. Early second-trimester (16 to 18 weeks) ultrasound determinations of the fetal biparietal diameter were used as the "gold standard" to test the validity of LNMP-based GA estimates in 11,045 women. The large majority of deliveries occurring at or near term showed LNMP estimates that were valid within plus or minus seven days of the ultrasound estimate. As the LNMP GA deviated progressively toward earlier or later GAs, however, the discrepancies became quite marked, especially for postterm dates. The positive predictive values of the LNMP GA estimates decreased dramatically from term (.949) to preterm (.775) to postterm (.119) deliveries. These systematic errors in menstrual GA estimates have profound implications for unnecessary induction, dysfunctional labor and cesarean section, and resultant neonatal and maternal morbidity.

Cohort Studies↗

PubMed1988

Assessment of fetal risk in postdate pregnancies.

To assess postdate fetal risk, pregnancies in which menstrual history was confirmed by early ultrasound examination were reviewed; 5915 pregnancies within 1 week of term, 1408 1 to 2 weeks postdate, and 340 at least 2 weeks postdate. Fetal distress and meconium release were twice as frequent and meconium aspiration eight times as frequent postterm. Birth asphyxia was unrelated to gestational age. Fractures and palsies were more frequent because of primiparity and macrosomia. Only one antepartum fetal death occurred in 1748 postdate pregnancies. Review of 674 perinatal deaths at 37 plus weeks in Quebec showed no increase in deaths postterm. The increase in fetal distress and meconium aspiration postterm without an increase in birth asphyxia or fetal death may reflect greater responsiveness of the more mature fetus to mild asphyxic insults. Findings of this study could not justify increased fetal monitoring in postdate pregnancies.

Asphyxia Neonatorum↗

PubMed1988

Obstetric consequences of postmaturity.

The obstetric management of 340 pregnancies delivered 2 or more weeks postterm and 1408 pregnancies delivered at 41 weeks is compared with that of 5915 pregnancies delivered at 39 to 40 weeks. In all patients menstrual dating was confirmed by early ultrasonographic examination. Postterm labor in primiparas resulted in a high cesarean section rate because of failure to progress; this increased rate was observed even after controlling for induction of labor and the size of the infant. We suggest that primiparas who go postterm often have increased uterine dysfunction. Uterine dysfunction accounts for the increase in the cesarean section rate and is a partial explanation for "failed" inductions.

Cesarean Section↗

PubMed1988

Cesarean section.

Cesarean section has become a common operation, but its complexity should not be underestimated. Often it must be done as an emergency without skilled assistants; at the same time the surgeon must deal with the maternal disorder that prompted the cesarean section and ensure the well-being of the fetus. Of further concern is the operative blood loss, which can be massive, and the postoperative morbidity, which is often high. The operative technique has evolved from an intraperitoneal vertical incision on the body of the uterus (classical cesarean section) to a near-complete reliance on a retroperitoneal transverse incision (lower segment cesarean section). The historic reason for this change was the fear of peritonitis postoperatively. Present-day practice favours the lower segment operation and emphasizes the reduced operative blood loss and the more secure uterine scar as reasons for the choice. Operative complications (injury to the fetus, lacerations of the uterus and vagina) are the result of inadequate uterine incisions. The classical incision has the advantage of being easily extended and thus has a continued purpose. Postoperative febrile morbidity is attributed to endometritis; the mixed aerobic and anaerobic bacteria of the vagina are the causal organisms. Febrile morbidity can be prevented by antibiotics given prophylactically.

Cesarean Section↗

PubMed1987

Importance of the duration of inhibition on intestinal carcinogenesis by difluoromethylornithine in rats.

The effect of the duration and sequence of inhibition of intestinal tumor formation in rats was studied to determine whether part time inhibition has any value. Four groups of male Sprague-Dawley rats were given 8 weekly s.c. injections of azoxymethane (AOM) 8 mg/rat. Three groups were given the inhibitor, difluoromethylornithine (DFMO) in the drinking water; one for the entire 26 weeks of the study, one for the first 13 weeks only, and one for the last 13 weeks. A control group was not given the inhibitor. While the continuous treatment group developed the least number of tumors per rat (1.5 vs. 5 for controls), still both groups given the inhibitor for just 13 weeks also developed fewer tumors than controls 5 vs. 3.2 (early treatment) and 5 vs. 2.8 (late treatment). These results show that part time inhibition, including its late application, does reduce intestinal tumor formation in rats.

Animals↗

PubMed1987

Care of the ureter in pelvic surgery.

Maintaining the integrity of the ureter is crucial in pelvic surgery. The ureter is best safeguarded by routine intraoperative exposure, which will also allow immediate recognition of injury to it. If doubts over possible injury persist, it is best to open the bladder. The flux of urine from the ureteric orifices or the retrograde passage of catheters will then confirm or deny clinical suspicions. If specialist help is unavailable, the pelvic surgeon must be able to perform simple ureteric repairs or temporize in a way that allows the safe delay of definitive surgery. End-to-end ureteric anastomosis and ureteroneocystostomy are straight-forward procedures that all pelvic surgeons should be familiar with. If they cannot be performed safely, the situation may be salvaged by draining the proximal ureter through the lateral abdominal wall; later, definitive surgery can be performed.

Female↗

PubMed1987

Stress incontinence of urine.

At rest, continence of urine depends on intraurethral pressure being higher than intravesical pressure. Intraurethral pressure is produced by elastic fibres and engorged urethral venous sinuses. Low intravesical pressure is preserved by bladder muscle relaxation. Urgency incontinence will result if bladder muscle does not relax. A sudden increase in abdominal pressure may overcome this urethral-vesical pressure gradient and cause stress incontinence. The mechanisms that prevent this from happening are unclear. The pressure gradient would not change if the abdominal pressure was transmitted equally to the urethra and the bladder. Continence could also be protected by pressure of the urethra against the symphysis pubis or pelvic muscles. Stress and urgency incontinence cannot be differentiated clinically with certainty. If surgical correction of stress incontinence is planned, preoperative urethrocystometry is mandatory. The Burch colposuspension is the operative procedure of choice. The suspension is done with Prolene sutures; their correct placement is ensured through the use of intraoperative cystostomy.

Female↗

PubMed1987

Postoperative gynecologic infections.

Postoperative gynecologic infections are caused by mixed aerobic and anaerobic bacteria that normally reside in the vagina. For the most part the infection, manifested by fever, resolves spontaneously, but occasionally serious problems result. Opinion now favours the prophylactic use of antibiotics before both abdominal and vaginal hysterectomy. Established infections are first treated with a combination of clindamycin and gentamicin.

Abscess↗

PubMed1986

Dysfunctional uterine bleeding.

Dysfunctional uterine bleeding is defined as abnormal uterine bleeding in the absence of organic disease. It is the result of anovulation or the abnormal local production of prostaglandins, and in each case the primary fault is inappropriate hormone formation. There are two approaches to diagnosis. The traditional one is primarily concerned with the exclusion of cancer of the endometrium; this concern results in the frequent resort to uterine curettage. The second approach is to limit curettage to patients whose symptoms are not ameliorated by medical therapy. The aim of medical treatment is either to produce secretory change in the endometrium or to decrease the formation of uterine prostaglandins. Intermittent progesterone treatment is used to cause secretory changes in the endometrium. Decreased production of the prostaglandins is achieved indirectly by causing atrophy of the endometrium or directly through the use of prostaglandin synthetase inhibitors. Surgery in the form of dilatation and curettage has no long-term therapeutic effect; hysterectomy is definitive therapy.

Adult↗

PubMed1986

Inhibition of intestinal carcinogenesis in rats: effect of difluoromethylornithine with piroxicam or fish oil.

An inhibitor of ornithine decarboxylase, difluoromethylornithine (DFMO), and two inhibitors of prostaglandin biosynthesis, piroxicam and menhaden fish oil, were examined for their effect on intestinal tumorigenesis in male Sprague-Dawley rats fed a 5% fat semisynthetic diet. Each agent was given individually in one of two doses as follows: DFMO, 0.05% and 0.1% in the drinking water; piroxicam, 65 mg/kg diet and 130 mg/kg diet; and menhaden fish oil, 1.25% and 2.50% of the diet. Additional animal groups were given combinations of the lower dose of DFMO and the lower dose of either piroxicam or fish oil. Intestinal tumors were induced by sc injections of azoxymethane (AOM; CAS: 25843-45-2) at 8 mg/kg (body wt) weekly for 8 weeks. Test diets were started 1 week prior to the first dose of AOM, and the rats were sacrificed 26 weeks later. Rats that received either dose of DFMO or the high dose of piroxicam developed significantly fewer intestinal tumors compared to controls. The low dose of piroxicam and the fish oil given at either dose level had no effect. The combination of the low dose of DFMO and the low dose of piroxicam reduced tumor formation more than either dose of DFMO alone, whereas the low dose of DFMO and fish oil together was no more effective than either dose of DFMO alone. These results show that a combination of a small amount of DFMO and piroxicam, each acting through a different mechanism, exerts an additive inhibitory effect on intestinal tumor formation in rats.

Animals↗

PubMed1986

Myomectomy.

If fibroids require treatment, hysterectomy is usually the therapy of choice. Myomectomy is best reserved for women who wish to preserve their uterus and have a single large fibroid tumour; it is not normally recommended for either abnormal uterine bleeding or infertility. The blood supply of leiomyomas is from the periphery and is such that degeneration frequently ensues. Degeneration, in particular the acute degeneration that may occur in pregnancy, is rarely an indication for operation. Myomectomy has been associated with considerable blood loss intraoperatively and prolonged morbidity postoperatively. The former can be avoided by limiting the uterine circulation during surgery with a uterine tourniquet and vascular clamps. Atraumatic intracapsular removal of the tumour and perfect hemostasis will minimize the latter.

Female↗

PubMed1986

Failed forceps.

Among 53 cases of failed forceps occurring in 6524 uncomplicated primiparous deliveries, depression at birth and encephalopathy occurred with similar frequency as when cesarean section was done for failure to progress in the second stage, and birth trauma was no more common than that with successful midforceps delivery. Factors predisposing to or associated with midforceps deliveries or second stage cesarean sections were short mothers, heavy babies, induced or prolonged labors, and fetal distress or meconium release in labor.

Cesarean Section↗

PubMed1985

Ectopic pregnancy.

Ectopic pregnancy is no longer dependent on laparotomy for definitive diagnosis. When patients present with massive hemoperitoneum, the diagnosis is usually obvious; but most patients do not present this way, so diagnostic aids are required. Culdocentesis is associated with unusually high false-negative and false-positive results. Laparoscopy is accurate but is an invasive procedure unwarranted in most cases for diagnosis. Although it is unusual to make the diagnosis of unruptured ectopic pregnancy by ultrasonography alone, when ultrasonography is combined with quantitative beta-subunit determinations of human chorionic gonadotropin, many ectopic pregnancies can be diagnosed before rupture occurs. The treatment of the woman with a ruptured ectopic pregnancy and in shock is immediate laparotomy and salpingectomy. Salpingostomy with removal of the ectopic mass and preservation of the tube may enhance a patient's subsequent fertility and may be useful in carefully selected women.

Diagnosis, Differential↗