Is group B streptococcal screening during pregnancy justified?

Twenty-eight per cent of women investigated during pregnancy were carriers of group B streptococci (GBS). The use of broth enrichment was the most significant factor in determining GBS carriage rates. GBS carriage decreased during pregnancy. Transmission of GBS from mother to baby was related to vaginal carriage but rectal carriage in pregnancy was the best predictor of maternal carriage at term. Rectal and vaginal swabs taken at 28 and 36 weeks correctly predicted 92% of intrapartum GBS carriage. Although accurate prediction of intrapartum GBS carriage is possible, mass screening for GBS in pregnancy is unlikely to be cost-effective in those countries with a low incidence of neonatal GBS sepsis.     

Is group B streptococcal screening during pregnancy justified?

Summary. Twenty-eight per cent of women investigated during pregnancy were carriers of group B streptococci (GBS). The use of broth enrichment was the most significant factor in determining GBS carriage rates. GBS carriage decreased during pregnancy. Transmission of GBS from mother to baby was related to vaginal carriage but rectal carriage in pregnancy was the best predictor of maternal carriage at term. Rectal and vaginal swabs taken at 28 and 36 weeks correctly predicted 92% of intrapartum GBS carriage. Although accurate prediction of intrapartum GBS carriage is possible, mass screening for GBS in pregnancy is unlikely to be cost-effective in those countries with a low incidence of neonatal GBS sepsis.     

Group B Streptococcal Bacteriuria in Pregnancy: An Evidence‐Based,Patient‐Centered Approach to Care

Screening and management of group B streptococcus (GBS) bacteriuria in pregnancy aims to reduce the incidence of pyelonephritis and GBS‐related neonatal morbidity and mortality. Universal screening and management of GBS bacteriuria in pregnancy are standards of care in the United States; however, some women may decline guideline‐based recommendations for screening, treatment, or intrapartum antibiotic prophylaxis. This article uses a case study approach to discuss evidence‐based, patient‐centered care for GBS bacteriuria in pregnancy as well as ethical incorporation of individual patient preferences and values.     

Prevalence of colonisation with group B Streptococci in pregnant women of a multi-ethnic population in The Netherlands

OBJECTIVE: This study was performed to determine the prevalence of GBS and to identify GBS colonisation risk factors in a multicultural population of pregnant women in The Netherlands. We calculated predictive values of cultures in pregnancy for intrapartum GBS carriage. STUDY DESIGN: From a total of 1702 women visiting several antenatal outpatient departments, rectovaginal swabs were collected at 35-37 weeks' gestation. In 761 women swabs were repeated at time of delivery. Carriage of GBS late in third trimester and at time of delivery was analysed in relation to age, parity, ethnicity and socio-economic status. RESULTS: Twenty-one percent was GBS carrier late in pregnancy. Compared to Europeans, African women were at a higher risk (29%, RR 1.4, CI 1.1-1.7) and Asian women were at lower risk (13%, RR 0.6, CI 0.4-0.8) for GBS carriage. No differences in colonisation were found between women with respect to age, parity or socio-economic background. Positive predictive value of GBS carriage at 35-37 weeks' gestation for carriage at time of parturition was 79% and negative predictive value was 93%. CONCLUSIONS: It was not possible to identify a group of pregnant women at high risk for GBS colonisation. Predictive values of antenatal genital group B streptococci cultures at 35-37 weeks' gestation for intrapartum GBS carriage are lower than previously reported.     

Epidemiology and predictive values of risk factors for neonatal group B streptococcal sepsis

OBJECTIVES: To determine the incidence of and factors affecting risk factors for neonatal group B streptococcal (GBS) sepsis and their predictive values for intrapartum GBS carriage; to calculate the proportions of women eligible for intrapartum antibiotic prophylaxis (IAP) using different selection protocols. DESIGN: Cohort study. SETTING: Antenatal clinics and labour wards of a community hospital and a tertiary referral centre in western Sydney POPULATION: Women attending antenatal clinics during the study periods were invited to participate. METHODS: Approximately 500 women attending antenatal clinics were screened for GBS carriage at 26-32 weeks gestation and at delivery, using several screening methods. Clinical risk factors for neonatal sepsis were recorded during labour. MAIN OUTCOME MEASURES: Incidence of antenatal anovaginal GBS carriage and clinical risk factors during labour, their predictive values for intra-partum GBS carriage and their relationship, if any, to demographic and obstetric factors. RESULTS: Antenatal and intra-partum GBS carriage rates were similar but varied from 18% to 27%, depending on screening methods. The best positive and negative predictive values of antenatal GBS culture, for intra-partum carriage, were 69% (95% confidence interval (CI) 64-74) and 92% (95% CI 50-94) respectively Clinical risk factors occurred in similar proportions of GBS carriers and non-carriers. CONCLUSIONS: Neither early antenatal screening nor clinical risk factors are reliable predictors of intra-partum GBS carriage. Intra-partum antibiotic prophylaxis based on GBS carriage or risk factors when carrier status is unknown would involve approximately 35% of women, compared with approximately 16% if based on risk factors only Both strategies would prevent similar proportions of neonatal deaths from GBS sepsis. Compliance with a preventive protocol is the most likely determinant of its overall effectiveness.     

Intrapartum GBS screening and antibiotic prophylaxis: a European consensus conference

Group B streptococcus (GBS) remains worldwide a leading cause of severe neonatal disease. Since the end of the 1990s, various strategies for prevention of the early onset neonatal disease have been implemented and have evolved. When a universal antenatal GBS screening-based strategy is used to identify women who are given an intrapartum antimicrobial prophylaxis, a substantial reduction of incidence up to 80% has been reported in the USA as in other countries including European countries. However recommendations are still a matter of debate due to challenges and controversies on how best to identify candidates for prophylaxis and to drawbacks of intrapartum administration of antibiotics. In Europe, some countries recommend either antenatal GBS screening or risk-based strategies, or any combination, and others do not have national or any other kind of guidelines for prevention of GBS perinatal disease. Furthermore, accurate population-based data of incidence of GBS neonatal disease are not available in some countries and hamper good effectiveness evaluation of prevention strategies. To facilitate a consensus towards European guidelines for the management of pregnant women in labor and during pregnancy for the prevention of GBS perinatal disease, a conference was organized in 2013 with a group of experts in neonatology, gynecology-obstetrics and clinical microbiology coming from European representative countries. The group reviewed available data, identified areas where results were suboptimal, where revised procedures and new technologies could improve current practices for prevention of perinatal GBS disease. The key decision issued after the conference is to recommend intrapartum antimicrobial prophylaxis based on a universal intrapartum GBS screening strategy using a rapid real time testing.     

Early-onset neonatal group B streptococcal sepsis: intrapartum antibiotic prophylaxis in the clinical setting.

OBJECTIVE: To evaluate how guidelines for the use of intrapartum antibiotics for the prevention of early-onset Group B streptococcal infection are utilized in a clinical setting. STUDY DESIGN: Review of maternal/infant records for the year 1993 in a perinatal center. RESULTS: Intrapartum antibiotics were administered to 77.8% of 443 Group B streptococcus (GBS)-colonized women. There were 452 infants born to these mothers, of which four developed GBS infection. During the same period, an additional 11 infants with GBS infection were born to women with "negative" or "unknown" GBS status (the women did not receive intrapartum antibiotics). Infants of GBS-colonized women who had not receive antibiotics were more likely to develop infection than GBS negative or unknown status, odds ratio 9.0, 95% confidence interval (2.8-29.1). CONCLUSION: This study supports the use of intrapartum antibiotics as an important means of preventing early-onset neonatal GBS infection but demonstrates problems that may be encountered in the clinical application of guidelines for intrapartum antibiotic prophylaxis.     

Compliance with protocols for prevention of neonatal group B streptococcal sepsis: practicalities and limitations

OBJECTIVE: To compare two protocols for intrapartum antibiotic prophylaxis (IAP) against neonatal group B streptococcal (GBS) sepsis, with respect to staff compliance, in a prospective cohort study in the obstetric units of a community hospital (A) and a university teaching hospital (B). METHODS: Cohorts comprised about 500 women attending antenatal clinics at each hospital (total 1096). Women identified as GBS carriers at 26-32 weeks' gestation and those who had intrapartum clinical risk factors (CRF) were eligible for IAP. Compliance was defined as the proportion of women eligible for IAP who received it according to protocol - as determined by audit of case records - and compared between hospitals and according to indication. RESULTS: Overall, 39% of women were eligible for IAP. Indications were GBS carriage alone (21%), CRF alone (13%) and both (5%). Compliance was similar for GBS carriers at both hospitals: 78% at Hospital A and 76% at Hospital B. However, because of the poor predictive value of screening before 32 weeks, only 65% of intrapartum GBS carriers actually received IAP. For women with CRF only, compliance was significantly lower at Hospital B than Hospital A (56 vs. 75%; p = 0.03). CONCLUSIONS: According to currently recommended protocols, about one-third of healthy women are eligible for intrapartum antibiotics to prevent neonatal GBS sepsis. In practice, antibiotics are often used inefficiently because of poor compliance with protocols and poor predictive values of selection criteria. Better implementation strategies should improve compliance, but GBS vaccines are needed to replace prophylactic antibiotic use, with its associated disadvantages.     

未足月胎膜早破抗生素使用

未足月胎膜早破（PPROM）病因复杂,但感染是首要病因。PPROM与感染互为因果。PPROM应用抗生素可以降低母儿发病率及延长孕周。PPROM确诊后通过评估适宜期待保胎者应第一时间行阴道和肛周的B族溶血性链球菌（GBS）筛查和中段尿培养,同时应用广谱抗生素。抗生素的选择建议氨苄青霉素联合红霉素,开始为静脉滴注,48 h后口服,共用药7 d。对于青霉素过敏者,应单独使用红霉素类抗生素。但GBS（+）,青霉素过敏者应启动其他敏感药物,孕周小于32周者应用抗生素治疗的益处更为明显。孕周≥34周者则建议积极引产。是否应用抗生素根据个体情况决定,GBS（+）者即使之前应用了抗生素治疗,在临产后仍应针对GBS应用青霉素类药物预防母胎感染。严重感染者,注意选用更广谱的抗生素。     

Ethical issues associated with routine screening and prophylaxis for group B streptococcus in pregnancy

An increased awareness of the impact of group B streptococcus (GBS) infection on neonataloutcome has prompted several seemingly discordant committee recommendations. Intrapartumantibiotics are effective in reducing the risk of neonatal morbidity when administered to a colonizedwoman who has a clinical condition that places her neonate at high risk for early-onset sepsis.However, less is known about the efficacy of prophylactic antibiotics in the colonized woman whodoes not have obvious risk factors. Some authorities have suggested that providers refrain fromadministering intrapartum antibiotics to colonized women who do not have any of these risk factors,primarily due to concerns about potential adverse reactions, selection of resistant pathogens, andcost-effectiveness. These recommendations may conflict with the desires of an informed womanwho weighs the real, albeit low, risk for serious neonatal disease against the lower perceived riskof adverse maternal sequelae from allergic reactions to the antimicrobial agents. Selective prophylaxisfor GBS disease that is limited to the colonized parturient with risk factors has the potentialfor creating conflict because maternal beneficence-based obligations of the physician may be atodds with maternal autonomy-based obligations. We believe that, given all currently availableinformation, providers have a moral obligation to discuss GBS screening and treatment issues withpatients. The potential for conflict between patient and physician at the time of delivery can beminimized through the use of preventive ethics, allowing patients to develop advance directivesregarding intrapartum management within the confines of reasonable and cost-effective care. Untila consensus is reached among experts, the most prudent approach would be to address such issuesproactively and individualize care based upon the overall estimation and anticipation of risk as wellas the patient's specific desires.     

Is antenatal group B streptococcal carriage a predictor of adverse obstetric outcome?

OBJECTIVES: While early-onset neonatal GBS sepsis is positively associated with premature birth and prolonged rupture of membranes, there is debate in the literature as to whether maternal GBS colonization is a predictor of adverse obstetric outcome. This is a critical issue to resolve for appropriate management (expectant vs. interventional management) of the patient presenting with premature rupture of membranes, who has no overt signs of sepsis, but who is colonized with GBS. METHODS: Since 1981 it has been hospital policy to screen all public patients antenatally for genital carriage of GBS by collection of a low vaginal swab at 28-32 weeks. All patients colonized with GBS antenatally are given penicillin as intrapartum chemoprophylaxis. Review of all GBS-colonized antenatal patients for a 12-month period (580 of 4,495 patients) and a randomized (every fourth consecutive antenatal patient) number of noncolonized patients (958) was made. Lower vaginal GBS colonization and other risk factors for preterm delivery were assessed using univariate and multivariate generalized linear modeling. RESULTS: In the study group, the maternal GBS colonization rate was 12.9%. When cofounding variables were controlled in a multivariate analysis, the association between antepartum GBS colonization and preterm labor and preterm rupture of membranes was not significant. CONCLUSION: Maternal antenatal carriage of GBS does not predict preterm labor. Therefore it is appropriate that expectant management occur for a GBS-colonized woman who ruptures her membranes, is not in labor, and has no evidence of sepsis.     

Asymptomatic bacteriuria in pregnancy

Screening for asymptomatic bacteriuria is a standard of obstetrical care and is included in most antenatal guidelines. There is good evidence that treatment of asymptomatic bacteriuria will decrease the incidence of pyelonephritis. All pregnant women should be screened for asymptomatic bacteriuria, and there are no new data that would indicate otherwise. Antibiotic treatment of asymptomatic bacteriuria is associated with a decrease in the incidence of preterm delivery or low birth weight, but the methodological quality of the studies means any conclusion about the strength of this association needs to be drawn cautiously. A better understanding of the mechanism by which treatment of asymptomatic bacteriuria could prevent preterm delivery is needed. While several rapid screening tests have been evaluated, none perform adequately to replace urine culture for detecting asymptomatic bacteriuria. Until there are data from well-designed trials that establish the optimal duration of therapy for asymptomatic bacteriuria, standard treatment courses are recommended.     

Risk factors for recurrence of group B streptococcus colonization in a subsequent pregnancy

OBJECTIVE: To document rates of recurrent group B streptococci (GBS) colonization in women with previous GBS colonization in an initial pregnancy and to assess maternal risk factors associated with recurrence. METHODS: A retrospective, longitudinal study was performed in a teaching hospital on women with GBS colonization who were pregnant between 2002 and 2006 and had at least one subsequent pregnancy during the same time period. When only the index and first subsequent pregnancy were analyzed, the cohort included 251 women. The rate of recurrence was estimated for GBS colonization in the pregnancy after the index pregnancy for GBS colonization. Multivariable regression models were constructed to model recurrence of GBS colonization in a subsequent pregnancy as functions of potential predictors to estimate relative risks and confidence intervals. RESULTS: The rate of recurrence of GBS colonization in the pregnancy subsequent to the index pregnancy was 38.2% (95% confidence interval 33.5-42.9%). Multivariable regression models showed that the time interval between the two pregnancies and the intensity of GBS colonization from the index pregnancy were predictive of recurrent GBS colonization. CONCLUSION: More than one third of women had recurrent GBS colonization in a subsequent pregnancy. These findings should assist clinicians in counseling women with GBS colonization about their risk for recurrence, the importance of appropriate prenatal GBS screening in a subsequent pregnancy, and intrapartum antibiotic prophylaxis for unknown GBS status.     

Acute myocardial infarction in pregnancy and the puerperium: a population-based study

OBJECTIVE: To estimate the population-based incidence and pregnancy outcomes of acute myocardial infarction (MI) in pregnancy. METHODS: Maternal and newborn hospital discharge records were linked to birth/death certificates for the 10-year period January 1, 1991, to December 30, 2000, for the majority (98%) of deliveries in California. This database was searched for the diagnosis of acute MI, demographic characteristics, and pregnancy outcomes. Patients were divided into 4 groups: antenatal diagnosis, intrapartum diagnosis, up to 6-week postpartum diagnosis, and those without the diagnosis of acute MI. All groups were compared by Student t test or chi(2) or both, where appropriate. RESULTS: A total of 151 women had an acute MI during the antepartum (38%), intrapartum (21%), or 6-week postpartum (41%) period, giving an incidence rate of 1 in 35,700 deliveries. The incidence rate increased over the study period. The maternal mortality rate was 7.3%, and maternal death only occurred in women with an acute MI before or at delivery (P < .01). Compared with women who did not have an acute MI, those with one were more likely to be older (30% were older than 35 years compared with 10%), multiparous (78% compared with 61%), non-Hispanic white (40% compared with 35%) or African Americans (15% compared with 7%). All measures of maternal and neonatal morbidity were increased in the acute MI group compared with those without an acute MI. Multivariate analysis identified chronic hypertension, diabetes, advancing maternal age, eclampsia, and severe preeclampsia as independent risk factors for acute MI. CONCLUSION: Acute MI during pregnancy remains a rare event, with significant maternal, fetal, and neonatal morbidity and mortality and maternal mortality limited to the antepartum and intrapartum period.     

Sickle cell disease in pregnancy

Sickle cell disease (SCD) is a chronic, multisystem disease. Despite decades of medical advances in SCD management, studies have revealed an increased risk of stillbirth, preterm delivery, small for gestational age, maternal mortality and preeclampsia, compared to the general population. Pregnant women with SCD should be cared for within the multidisciplinary team, comprised of specialist obstetricians, high risk midwives and haematologists. A national confidential enquiry into patient outcomes and death (NCEPOD), expressed concerns with a lack of consistent care for SCD patients in pregnancy. Within the UK, there is great geographical variation in the prevalence of SCD, with the highest incidence in large urban, multicultural centres. Trainee obstetricians practising outside of these areas may not gain substantial experience in managing these patients: therefore this review aims to highlight the key antenatal, intrapartum and postnatal elements involved in managing pregnant women with SCD.     

Bacteruria with group-B streptococcus: is it a risk factor for adverse pregnancy outcomes?

Objective: To investigate pregnancy outcomes of patients with and without group-B streptococcus (GBS) bacteriuria. Methods: A retrospective study comparing pregnancy outcomes of women with GBS bacteriuria during pregnancy, those with positive GBS vaginal cultures and those without GBS colonization during pregnancy was conducted. Results: A significant linear association was found with regard to intrapartum fever (U-GBS 0.5%, V-GBS 0.3%, no GBS 0.1%, p?=?0.001) and chorioamnionitis (U-GBS 3.3%, V-GBS 1%, no GBS 0.7%, p?=?0.001). In addition preterm delivery (15.3% vs. 7.9%, p?=?0.001) and premature rupture of membranes (10.7% vs. 7.9, p?=?0.001) were significantly higher in the U-GBS group compared to no GBS. Woman with U-GBS had higher rates of diabetes mellitus, hypertensive disorders, and habitual abortions as well as a higher risk for intrauterine growth restriction (IUGR). In addition patients with U-GBS underwent induction of labor and cesarean delivery more frequently. Conclusions: Our study showed a significant association between U-GBS and adverse obstetrical outcomes. In addition a linear association was found between GBS culture location and obstetric complications. However, GBS was not associated with adverse perinatal outcome in our population.     

Zinc status, pregnancy complications, and labor abnormalities

Maternal plasma zinc levels, red blood cell levels, and serum alkaline phosphatase activity were used as indices of zinc status in 279 pregnant women at delivery and were compared with the incidence of complications during the antenatal period and major dysfunctional labor patterns. The median values for plasma zinc, red blood cell zinc, and alkaline phosphatase were used as cutoff points to subdivide the patient population into "low" and "high" groups. Low levels of maternal plasma zinc were associated with more complications in the antenatal or intrapartum periods than maternal levels of either alkaline phosphatase or red blood cell zinc. Plasma zinc levels less than the median value were more commonly associated with mild toxemia (p = 0.02), vaginitis (p = 0.01), and postdates (p = 0.01) in the antenatal period. During the intrapartum period, low plasma zinc levels were associated with a prolonged latent phase (p = 0.05), a protracted active phase (p = 0.04), labor greater than 20 hours (p = 0.03), second stage greater than 2.5 hours (p = 0.01), and cervical and vaginal lacerations (p = 0.02). Low levels of maternal alkaline phosphatase were strongly associated with a history of previous stillbirth (p = 0.0005). A low maternal red blood cell zinc level was not associated with complications during either period. Since a low plasma zinc level is a valid predictor of pregnancy complications and abnormal labor, the results suggest that plasma zinc screening, as part of the patient's antenatal workup should be evaluated.     

Prophylactic antibiotics in obstetrics

Drugs should only be prescribed during pregnancy when there are clear indications; the risks of possible adverse side effects in the mother or fetus must be weighed against the likely benefits. Despite this concern, antibiotics are used during pregnancy, including 5% during the first trimester. There are few indications for the prophylactic use of antibiotics in pregnancy, but they are of value in a small number of conditions, such as Lancefield group B streptococcal carriage, recurrent bacteriuria, bacterial vaginosis, premature ruptured membranes, Caesarean section and in pregnant women with known cardiac lesions.In general, the full adult dose should be used when treating infections in pregnant women and for the prevention of infection prior to surgery. However, low-dose antibiotics for protracted periods of time can be used in the prevention of recurrent bacteriuria. Those antibiotics known to be associated with possible adverse events should be avoided and those antibiotics which have dose-related side effects should be monitored and the dose adjusted accordingly.     

Recolonization of group B Streptococcus (GBS) in women with prior GBS genital colonization in pregnancy

Objective: The purpose of the study is to evaluate the incidence of women with prior GBS genital colonization who have recolonization in subsequent pregnancies. Methods: This is a retrospective, cohort study of patients with a prior GBS genital colonization in pregnancy and a subsequent pregnancy with a recorded GBS culture result, from January 2000 through June 2007. Documentation of GBS status was through GBS culture performed between 35 to 37 weeks gestation. Exclusion criteria included pregnancies with unknown GBS status, patients with GBS bacteriuria, women with a previous neonate with GBS disease and GBS finding prior to 35 weeks. Data was analyzed using SPSS 15.0. The sample proportion of subjects with GBS genital colonization and its confidence interval were computed to estimate the incidence rate. Logistic regression was performed to assess potential determinants of GBS colonization. Regression coefficients, odds ratios and associated confidence intervals, and p-values were reported, with significant results reported. Results: There were 371 pregnancies that met the test criteria. There were 151 subsequent pregnancies with GBS genital colonization and 220 without GBS recolonization. The incidence of GBS recolonization on patients with prior GBS genital colonization was 40.7% (95% confidence interval 35.7–45.69%). The incidence rate for the sample was significantly larger than 30% (p < .001), which is the estimated incidence rate for all pregnant women who are GBS carriers regardless of prior history. Conclusion: These results suggest that patients with a history of GBS are at a significantly higher risk of GBS recolonization in subsequent pregnancies.     

Antibiotic resistance patterns of group B streptococcus in antenatal genital cultures

OBJECTIVE: To identify the antibiotic susceptibility patterns of group B streptococcus (GBS) isolated from antenatal genital screening cultures. STUDY DESIGN: One hundred thirty-five sequential GBS isolates underwent susceptibility testing by Kirby-Bauer disk diffusion to a variety of commonly used antibiotics. RESULTS: All isolates were susceptible to cefazolin, chloramphenicol and vancomycin. Resistance to clindamycin and erythromycin, the currently recommended alternative antibiotics for intrapartum GBS prophylaxis in penicillin-allergic women, was found in 8.2% and 9.6% of GBS isolates tested, respectively. CONCLUSION: These findings raise concerns regarding the need for both confirmation of a history of penicillin allergy in pregnant women and performance of antibiotic susceptibility testing on GBS isolated in genital screening cultures from penicillin-allergic patients.