Philip B. Mead

Epidemiology of bacterial vaginosis.

Studies of the prevalence of and risk factors for bacterial vaginosis are flawed by imprecision in diagnosis, failure to study large and well-characterized populations, selection bias, and failure to correct for confounding variables. Prevalences range from 5% for women without any symptoms to 25% for those with gynecologic symptoms. Although bacterial vaginosis is associated with nonwhite race and intrauterine contraceptive device use, these may represent surrogate markers for other presently unappreciated risk factors.

Vaginal-Rectal Colonization With Group A Streptococci in Late Pregnancy

OBJECTIVE: To determine the vaginal-rectal colonization rate with group A streptococci in late pregnancy. METHODS: All patients delivering at a northern New England hospital over a 38 month period had 35-37 week vaginal-rectal swabs cultured for group A and group B streptococci, using selective media and slide agglutination. RESULTS: Six thousand nine hundred forty-four screening cultures were obtained. Among these 1,393 were positive for group B streptococci and 2 for group A streptococci, yielding colonization rates of 20.1% and 0.03%, respectively. CONCLUSIONS: Vaginal-rectal colonization with group A streptococci is rare, arguing against the need for establishing group A streptococcal screening programs in pregnancy. An approach for managing this uncommon finding is presented.

Exhaled carbon monoxide and urinary cotinine as measures of smoking in pregnancy

We examined the relationships among self-reported cigarette consumption, exhaled carbon monoxide, and urinary cotinine/creatinine ratio in pregnant women. Information on these measures of smoking was collected at first and 36th week prenatal visits. Correlations between cigarette consumption and exhaled carbon monoxide were .65 at the first visit and .70 at the 36th-week visit. For urinary cotinine/creatinine ratio, the correlations were .61 and .65, respectively, at these visits. Correlations with change in cigarette consumption between the two visits were .37 for change in carbon monoxide and .33 for change in urinary cotinine/creatinine ratio. Urinary cotinine/creatinine ratio had slightly higher overall agreement with self-reported smoking status and was less likely to misclassify smokers than carbon monoxide. We conclude that urinary cotinine/creatinine ratio is the more accurate measure for validating smoking status among pregnant women, but exhaled carbon monoxide is the better measure of cigarette consumption and of changes in consumption.

Prevention of perinatal group B streptococcal infection: Current controversies

Group B streptococcus (GBS) is the most frequent cause of neonatal sepsis in the United States. The Centers for Disease Control and Prevention (CDC) issued guidelines for its prevention in 1996. This article details areas of controversy with those guidelines and offers recommendations for resolution. We recommend that a prevention policy be adopted by all hospitals. If a screening-based policy is chosen, compliance is essential. Penicillin is the antibiotic of choice for GBS prevention. Increasing resistance to clindamycin and erythromycin might eliminate them as alternative choices in patients allergic to penicillin. Group B streptococcal prophylaxis might not be necessary in women who have repeat elective cesarean delivery. In asymptomatic women, a positive urine culture for GBS should be considered clinically equivalent to a positive vaginal or rectal sample for screening. Neonatal sepsis caused by organisms other than GBS must be monitored carefully by all hospitals providing obstetrics services.

Smoking in pregnancy, exhaled carbon monoxide, and birth weight

Objective To examine the relation of cigarette consumption and exhaled carbon monoxide levels during pregnancy and to assess the effect of these smoking measures on birth weight. Methods Cigarette consumption and exhaled carbon monoxide levels were recorded at the first prenatal visit and the 36-week visit from women who smoked early in pregnancy. Analysis of variance was used to compare birth weights for differing levels of cigarette consumption and exhaled carbon monoxide. Correlation and regression analyses were used to estimate the effects of the smoking measures at both prenatal visits on birth weight. Results Cigarette consumption and exhaled carbon monoxide levels at both visits were associated significantly with birth weight. After the first prenatal visit, a reduction in cigarette consumption of at least nine cigarettes per day or in exhaled carbon monoxide of 8 parts per million (ppm) was associated with gains in birth weight of 100 g or more. The proportion of low birth weight (LBW) infants increased significantly with increasing levels of cigarette consumption and with increasing concentrations of exhaled carbon monoxide. Conclusion Substantial reductions in cigarette consumption or in exhaled carbon monoxide levels after the first prenatal visit are needed to achieve gains in birth weight. Not smoking, or having an exhaled carbon monoxide level less than 5 ppm minimizes the likelihood of having an LBW infant.

Management of preterm premature rupture of membranes: a Lack of a national consensus

A questionnaire concerning the management of women with preterm premature rupture of membranes was sent to the members of the Society of Perinatal Obstetricians. Expectant management was recommended by 97% of the respondents. There was no consensus about the role and frequency of steroids, blood work, ultrasound examination, and fetal monitoring in the follow-up of these patients.

Preventing Neonatal Herpes — Current Strategies

DESPITE more than three decades of research, there is no effective strategy for preventing most cases of neonatal infection with herpes simplex virus (HSV). From the early 1970s until 1988, it was ...

Incidence of infections associated with the intrauterine contraceptive device in an isolated community.

In an attempt to estimate more precisely the frequency of infections associated with the intrauterine contraceptive device (IUD), all gynecologic morbidity resulting from infection and occurring during a two-year period in an isolated community was reviewed. Ten septic abortions occurred, and all but one were associated with IUD use. In 26 gynecologic inpatients (41 per cent of all admissions for acute pelvic inflammatory disease), pelvic infection was associated with IUD use. In contradistinction to the septic abortion data, implicating only the Dalkon Shield, the gynecologic infections were associated with various types of devices.

Incidence of genital herpes simplex virus at the time of delivery in women with known risk factors

A total of 143 women with known risk factors for genital herpes simplex virus had cultures performed at the time of delivery. A total of 123 were without symptoms, of which three (2.4%) had positive herpes simplex virus cultures at the time of delivery. Fifteen women had lesions clinically consistent with genital herpes simplex virus at the time of delivery and five (33.3%) were culture positive. Five women had only prodromal symptoms of genital herpes simplex virus, but two of these (40%) had positive herpes simplex virus cultures from the site of previous lesions. Of the 10 women with positive herpes simplex virus cultures in this group of 143, no infant was delivered with evidence of neonatal herpes simplex virus infection, including two who had vaginal deliveries. The results of this study support the recommendations that in women without symptoms but with known risk factors for genital herpes simplex virus, a trial of vaginal delivery be allowed and that in women with either a lesion clinically consistent with genital herpes simplex virus or prodromal symptoms of genital herpes simplex virus a cesarean section be the mode of delivery.

Selective maternal culturing to identify group B streptococcal infection

During a 5-year period vaginal cultures were obtained from all women with an obstetric history of premature onset of labor or premature rupture of membranes. With these indications, 1,213 (12.7%) of all parturient patients were cultured and 10.2% of those cultured were colonized with group B beta-hemolytic streptococci. Maternal colonization did not correlate with ABO blood group, although a significantly higher percentage of Rh negative women were colonized (p < 0.01). During this 5-year period, 20 infants had documented early-onset infection (sepsis or meningitis) with group B beta-hemolytic streptococci. All 10 infants had a maternal history of premature onset of labor and/or premature rupture of membranes. Mothers of eight infants were cultured and seven of these cultures were positive. Approximately one of every 20 infants designated at high risk actually developed early-onset disease. Selective maternal culturing effectively identifies those infants as risk for early-onset group B streptococcal disease.