Pertussis Non-Vaccination During Pregnancy Despite Advice From Prenatal Care Providers.

OBJECTIVE: The purpose of this study was to measure the proportion of non-vaccination for pertussis in mothers in Canada who had been advised by their prenatal care provider to get vaccinated, and to identify sociodemographic factors and beliefs associated with non-vaccination. METHODS: The Survey on Vaccination during Pregnancy (part of childhood National Immunization Coverage Survey) included biological mothers of children born from September 2018 to March 2019. This analysis was restricted to 2657 mothers who had been advised by their prenatal care provider to get vaccinated against pertussis during pregnancy and knew whether or not they had been vaccinated. RESULTS: Of those who had been advised to get vaccinated against pertussis, 21% were not. This rate varied across provinces and territories, ranging from 9% in Prince Edward Island to 32% in Newfoundland and Labrador. Factors independently associated with pertussis non-vaccination included lower household income, having had past live births, and having received prenatal care from an obstetrician-gynecologist or a midwife compared to a family doctor. The risk of pertussis non-vaccination despite prenatal care advice was higher for those who disagreed that the baby would be at greater risk of pertussis if the mother did not get vaccinated. It was also higher for those who disagreed with statements regarding perceived benefits of vaccination. Conversely, disagreement with statements on perceived barriers was negatively associated with pertussis non-vaccination. CONCLUSION: These findings highlight the underlying factors associated with non-vaccination against pertussis despite prenatal care provider recommendation. Some inaccurate beliefs about pertussis and vaccination during pregnancy persist, leading to non-vaccination.

Comparing adverse neonatal and maternal outcomes of chlamydia, gonorrhoea, and syphilis infections and co-infections in pregnancy.

BACKGROUND: While maternal sexually transmitted infections (STIs) during pregnancy have been extensively studied, fewer studies have directly compared the associations of different infections and co-infections or investigated the association between STIs in pregnancy and maternal outcomes. OBJECTIVES: We examine associations between STIs and co-infections in pregnancy on risks of adverse neonatal and maternal outcomes. METHODS: Data from the 2019 US natality files (n = 3,747,882) were used to assess the associations between STIs in pregnancy on adverse pregnancy outcomes. Five mutually exclusive STI groups were examined: a single chlamydia, syphilis, or gonorrhoeal infection, chlamydia and gonorrhoea co-infection, and syphilis co-infection (with chlamydia, gonorrhoea, or both). Demographic and obstetric characteristics among each STI group were compared to those of an uninfected comparison group. Prevalence ratios (PR) of adverse neonatal outcomes (preterm birth, small for gestational age [SGA] births, and 5-min APGAR (Appearance, Pulse, Grimace, Activity, and Respiration) score < 7) and maternal outcomes (gestational hypertension) by STI status were examined using log-binomial regression. RESULTS: Increased prevalence of preterm birth was apparent, especially among those with a syphilis infection (PR 1.19, 95% confidence intreval [CI] 1.10, 1.30 for single infections and PR 1.31, 95% CI 1.10, 1.57 for co-infections). All STI groups, except gonorrhoea and chlamydia co-infections, were associated with an increased prevalence of gestational hypertension, with the strongest association among those with syphilis co-infections (PR 1.41, 95% CI 1.13, 1.76). CONCLUSIONS: An increased prevalence was of preterm birth and low APGAR scores were associated with syphilis infection. Increased prevalence of GH among those with STIs warrants further investigation into the relationships and corresponding mechanisms of STIs in pregnancy on adverse maternal outcomes.

Pertussis Vaccination in Canadian Pregnant Women, 2018-2019.

OBJECTIVE: This study was undertaken to measure the uptake of pertussis vaccination during pregnancy in Canada and to identify sociodemographic factors associated with non-vaccination. METHODS: A total of 5091 biological mothers of children born between September 2, 2018, and March 1, 2019, were interviewed about pertussis vaccination during their pregnancy. RESULTS: Among 4607 mothers who recalled whether they had been vaccinated for pertussis, 43% had been vaccinated and 57% had not. The main reason given by mothers for not having been vaccinated was not being aware that pertussis vaccination was recommended. Factors independently associated with non-vaccination were being born outside Canada, lower household income, living in a province or territory where pertussis vaccination was not provided free of charge, having had previous live births, and having received maternity care from a midwife. CONCLUSION: Advice from the maternity care provider is an important driver of pertussis vaccination during pregnancy.

Knowledge of Congenital CMV, Risk Behaviours for CMV Acquisition, and Acceptance of an Educational Infographic Among Postpartum Women: A Pilot Study.

Congenital cytomegalovirus (cCMV) infection in the newborn can present with sensorineural hearing loss and microcephaly. The objectives of this study were to determine baseline knowledge of cCMV and the acceptability of an infographic about cCMV among a group of postpartum women. Participants completed a questionnaire assessing their perceptions of an infographic as well as their knowledge and risk behaviours for acquisition of CMV. Of all 140 respondents, 119 (85%) had no prior knowledge of cCMV, and all 12 women (8.6%) who viewed the infographic indicated that it was helpful. Our study also demonstrated that passive dissemination of an infographic in clinics results in limited viewership.

Association of SARS-CoV-2 Infection During Pregnancy With Maternal and Perinatal Outcomes.

Importance: There are limited high-quality, population-level data about the effect of SARS-CoV-2 infection on pregnancy using contemporaneous comparator cohorts. Objectives: To describe maternal and perinatal outcomes associated with SARS-CoV-2 infection in pregnancy and to assess variables associated with severe disease in the pregnant population. Design, Setting, and Participants: CANCOVID-Preg is an observational surveillance program for SARS-CoV-2-affected pregnancies in Canada. This analysis presents exploratory, population-level data from 6 Canadian provinces for the period of March 1, 2020, to October 31, 2021. A total of 6012 pregnant persons with a positive SARS-CoV-2 polymerase chain reaction test result at any time in pregnancy (primarily due to symptomatic presentation) were included and compared with 2 contemporaneous groups including age-matched female individuals with SARS-CoV-2 and unaffected pregnant persons from the pandemic time period. Exposure: SARS-CoV-2 infection during pregnancy. Incident infections in pregnancy were reported to CANCOVID-Preg by participating provinces/territories. Main Outcomes and Measures: Maternal and perinatal outcomes associated with SARS-CoV-2 infection as well as risk factors for severe disease (ie, disease requiring hospitalization, admission to an intensive care unit/critical care unit, and/or oxygen therapy). Results: Among 6012 pregnant individuals with SARS-CoV-2 in Canada (median age, 31 [IQR, 28-35] years), the greatest proportion of cases were diagnosed at 28 to 37 weeks' gestation (35.7%). Non-White individuals were disproportionately represented. Being pregnant was associated with a significantly increased risk of SARS-CoV-2-related hospitalization compared with SARS-CoV-2 cases among all women aged 20 to 49 years in the general population of Canada (7.75% vs 2.93%; relative risk, 2.65 [95% CI, 2.41-2.88]) as well as an increased risk of intensive care unit/critical care unit admission (2.01% vs 0.37%; relative risk, 5.46 [95% CI, 4.50-6.53]). Increasing age, preexisting hypertension, and greater gestational age at diagnosis were significantly associated with worse maternal outcomes. The risk of preterm birth was significantly elevated among SARS-CoV-2-affected pregnancies (11.05% vs 6.76%; relative risk, 1.63 [95% CI, 1.52-1.76]), even in cases of milder disease not requiring hospitalization, compared with unaffected pregnancies during the same time period. Conclusions and Relevance: In this exploratory surveillance study conducted in Canada from March 2020 to October 2021, SARS-CoV-2 infection during pregnancy was significantly associated with increased risk of adverse maternal outcomes and preterm birth.

Guideline No. 420: Cytomegalovirus Infection in Pregnancy.

OBJECTIVE: To provide an update on current recommendations for cytomegalovirus (CMV) infection during pregnancy. The objectives of this guideline are: TARGET POPULATION: Patients of child-bearing age, pregnant patients, and patients planning a pregnancy. BENEFITS, HARMS, AND COSTS: The patient partners urged us to make awareness of preventive strategies a high priority, despite concern that discussing CMV with patients could cause unnecessary anxiety. CMV educational interventions have shown benefits from increased awareness of cCMV prevalence and preventive strategies among providers, patients, and families. EVIDENCE: We searched MEDLINE, EMBASE, and CENTRAL databases for CMV in pregnancy. The search terms were developed using MeSH terms and keywords (Appendix). The results were filtered for articles published between January 2010 and October 2020 and systematic reviews, meta-analyses, clinical trials, and observational studies. The main inclusion criteria were pregnant patients and infants, as the target population, and CMV infection, as the diagnosis of interest. Recommendations are graded according to the U.S. Preventive Services Task Force grade of recommendations and level of certainty. VALIDATION METHODS: We collaborated with patient partners, including members of CMV Canada (cmvcanada.com). In formulating our recommendations, we included patients' voices to add a unique and valuable perspective, thus ensuring that our recommendations are relevant to the patient-provider partnership. INTENDED AUDIENCE: All perinatal health care providers. RECOMMENDATIONS (GRADE AND LEVEL OF CERTAINTY IN PARENTHESES).

Presence of Precore (C)/C Promoter Mutants in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B (CHB) Carriers During Pregnancy Does Not Correlate with Increased Risk of Liver Disease in 4 Years of Follow-Up.

PURPOSE: HBV precore (PC) and basal core promoter (BCP) mutants are associated with liver disease severity, yet have been suggested to protect against HBV vertical transmission. HBV within peripheral blood mononuclear cells (PBMC) has been reported in association with intrauterine HBV infection. We analyzed HBV replication status in PBMC and PC/BCP mutants in PBMC from pregnant chronic hepatitis B (CHB) patients. METHODS: Pregnant CHB carriers were assessed for HBeAg, HBV-DNA, ALT in second-third trimester and liver stiffness measurement (LSM) postpartum. HBV-DNA, HBV-cccDNA, and HBV-mRNA were tested in PBMC by in-house PCR. BCP/PC variants were determined by Sanger sequencing and analyzed using MEGA7. RESULTS: In 37 CHB pregnant carriers, median age 32 years, 53% Asian, median ALT 19 versus 26 U/L, median HBV-DNA 2.6 versus 8.1 logIU/mL (untreated vs. treated), eight HBeAg+, with genotype 10%A, 29%B, 21%C, 10%D, 19%E, eight received tenofovir in pregnancy to reduce vertical transmission risk. HBV-DNA was detected in ~ 55% (25/45) PBMC, and PC/BCP mutations were found in 36% (9/25) and 4% (1/25), respectively. All infants received HBV immunoprophylaxis and tested HBV surface antigen negative at 9-12 months of age. During a median 4 years (IQR 3-5), follow-up all mothers showed normal LSM, with no significant change in ALT, HBeAg status, or HBV-DNA levels compared to baseline in untreated CHB carriers. CONCLUSION: In this multiethnic cohort of pregnant CHB carriers, HBV replicative intermediates and PC/BCP mutants were found in significant proportion of PBMC, but were not associated with increased risk of HBV immunoprophylaxis failure or liver disease severity over long-term follow-up.

CtpB is a plasma membrane copper (I) transporting P-type ATPase of Mycobacterium tuberculosis.

BACKGROUND: The intracellular concentration of heavy-metal cations, such as copper, nickel, and zinc is pivotal for the mycobacterial response to the hostile environment inside macrophages. To date, copper transport mediated by P-type ATPases across the mycobacterial plasma membrane has not been sufficiently explored. RESULTS: In this work, the ATPase activity of the putative Mycobacterium tuberculosis P1B-type ATPase CtpB was associated with copper (I) transport from mycobacterial cells. Although CtpB heterologously expressed in M. smegmatis induced tolerance to toxic concentrations of Cu2+ and a metal preference for Cu+, the disruption of ctpB in M. tuberculosis cells did not promote impaired cell growth or heavy-metal accumulation in whole mutant cells in cultures under high doses of copper. In addition, the Cu+ ATPase activity of CtpB embedded in the plasma membrane showed features of high affinity/slow turnover ATPases, with enzymatic parameters KM 0.19 ± 0.04 µM and Vmax 2.29 ± 0.10 nmol/mg min. In contrast, the ctpB gene transcription was activated in cells under culture conditions that mimicked the hostile intraphagosomal environment, such as hypoxia, nitrosative and oxidative stress, but not under high doses of copper. CONCLUSIONS: The overall results suggest that M. tuberculosis CtpB is associated with Cu+ transport from mycobacterial cells possibly playing a role different from copper detoxification.

A Systematic Review of Barriers to Vaccination During Pregnancy in the Canadian Context.

OBJECTIVE: Although vaccination in pregnancy has the potential to affect maternal and infant morbidity and mortality dramatically, uptake of recommended vaccinations in pregnancy remains low. The objective of this study was to identify barriers and facilitators of vaccination during pregnancy in Canada. METHODS: The Medline database and the tables of contents of four relevant Canadian journals were screened to identify all studies that considered barriers and/or facilitators to vaccination during pregnancy, specifically in Canadian settings. Citations were screened, and a narrative synthesis of findings was undertaken given the heterogeneity of study design. RESULTS: In total, 17 studies met inclusion criteria, most with a focus on the seasonal and pandemic influenza vaccines. Facilitators and barriers were identified at the level of the patient and the provider. At both levels, knowledge was an important facilitator of vaccine acceptance during pregnancy and was notably improved in studies following the 2009 pandemic H1N1 influenza outbreak compared with earlier studies. Vaccine endorsement by a prenatal care provider and clear messages of safety for the fetus emerged as key motivators. Few studies addressed system-level barriers or interventions for improving vaccine uptake during pregnancy in the Canadian setting. CONCLUSION: Common themes have emerged from the Canadian literature addressing barriers and facilitators of vaccination during pregnancy. However, there is a paucity of literature to suggest strategies to improve the uptake of vaccination during pregnancy in Canadian settings. Further research is urgently needed given the expanding role of vaccination during routine prenatal care.

Vaccination Against Influenza in Pregnancy: A Survey of Canadian Maternity Care Providers.

OBJECTIVE: Influenza vaccine uptake among Canadian pregnant individuals is suboptimal. Failure to incorporate vaccination into routine prenatal care and a lack of recommendations from healthcare providers are recognized as barriers to vaccination. The aim of this study was to assess Canadian maternity care providers' knowledge, attitudes, and practices regarding influenza vaccination in pregnancy. METHODS: A cross-sectional Web-based questionnaire was sent during July and August 2017 to family physicians, obstetricians-gynaecologists, midwives, pharmacists, and nurses who care for pregnant individuals. A multivariable logistic regression model was used to determine variables independently associated with providers' recommendation of the influenza vaccine in pregnancy. RESULTS: The analysis included 1061 providers. Most participants (85%) reported being vaccinated against influenza themselves, and 72% reported recommending the influenza vaccine to all of their pregnant patients during the previous influenza season. Participants' attitudes regarding influenza vaccination during pregnancy were generally positive: 64% strongly agreed that pregnant individuals are at an increased risk of complications from influenza, and 69% strongly agreed that it is safe to vaccinate pregnant individuals against influenza. The main determinants of participants' recommendations for influenza vaccination to all pregnant patients were following official recommendations on influenza vaccination, discussing vaccines with most or all pregnant individuals seen in their practice, and being vaccinated themselves during the previous influenza season. CONCLUSION: Enhancing influenza vaccine uptake in pregnancy is largely dependent on maternity care providers' recommendations. This study provides valuable insight on providers' knowledge, attitudes, and practices.

No 368 - La rubéole durant la grossesse.

OBJECTIF: Examiner l'épidémiologie, l'histoire naturelle, la prise en charge et la prévention de la rubéole pendant la grossesse. Cela aidera les prestataires de soins obstétricaux à conseiller leurs patientes sur les effets potentiellement dévastateurs de la rubéole sur le développement du fœtus et sur l'importance de vacciner les femmes susceptibles. RéSULTATS: Les résultats évalués incluent l'infection congénitale par le virus de la rubéole, la séroconversion maternelle et la réponse aux vaccins contenant la rubéole. DONNéES PROBANTES: Des recherches ont été effectuées dans les bases de données Medline, PubMed, EMBASE et Cochrane sur des articles liés à la rubéole pendant la grossesse publiés en anglais entre 1985 et 2017. Les résultats ont été limités aux revues systématiques, aux essais contrôlés randomisés / essais cliniques contrôlés et aux études d'observation. La littérature grise (non publiée) a été identifiée grâce à la recherche sur les sites Web d'agences d'évaluation des technologies de la santé et liées à ces dernières, de lignes directrices de pratique clinique, de registres d'essais cliniques et de sociétés nationales et internationales médicales. VALEURS: La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau 1). Les recommandations pour la pratique sont classées selon la méthode décrite dans ce rapport. MIS-A-JOUR à LA DIRECTIVE: Une revue des données probantes sera menée cinq ans après la publication de la présente directive clinique afin d'évaluer si une mise à jour complète ou partielle s'impose. Si de nouvelles données probantes importantes sont publiées avant la fin de ces cinq ans, une mise à jour tenant compte des nouvelles connaissances et recommandations sera publiée. COMMANDITAIRE: La Société des obstétriciens et gynécologues du Canada. RECOMMANDATIONS.

No. 368-RUBELLA IN PREGNANCY.

OBJECTIVE: To review the epidemiology, natural history, evaluation, and prevention of rubella infection during pregnancy. This will aid obstetric care providers in counseling their patients regarding potentially devastating effects on the developing fetus and the importance of vaccinating susceptible women as appropriate. OUTCOMES: Outcomes evaluated include fetal rubella infection, maternal seroconversion and response to rubella-containing vaccines. EVIDENCE: Medline, PubMed, EMBASE, and Cochrane databases were searched for articles in English on subjects related to rubella infection during pregnancy betweenn 1985 and 2017. Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. Other (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. VALUATION METHODS: The quality of the evidence is rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Recommendations for practice are ranked according to the method described in this Report. GUIDELINE UPDATE: The guideline will be reviewed 5 years after publication to decide if an update is required. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations SPONSOR: Society of Obstetricians and Gynaecologists of Canada.

No. 357-Immunization in Pregnancy.

OBJECTIVE: To review the evidence and provide recommendations on immunization in pregnancy. OUTCOMES: Outcomes evaluated include effectiveness of immunization and risks and benefits for mother and fetus. EVIDENCE: The Medline and Cochrane databases were searched for articles published up to January 2017 on the topic of immunization in pregnancy. VALUES: The evidence obtained was reviewed and evaluated by the Infectious Diseases Committee of the SOGC under the leadership of the principal authors, and recommendations were made according to guidelines developed by the Canadian Task Force on Preventive Health Care (Table 1). BENEFITS, HARMS, AND COSTS: Implementation of the recommendations in this guideline should result in more appropriate immunization of pregnant and breastfeeding women, decreased risk of contraindicated immunization, and better disease prevention.

N° 342-L'hépatite B et la grossesse.

OBJECTIF: Examiner l'épidémiologie, l'histoire naturelle, l'évaluation et le traitement de l'infection au virus de l'hépatite B (VHB) durant la grossesse. Cela aidera les fournisseurs de soins obstétricaux à conseiller leurs patientes quant aux risques périnataux et aux options de prise en charge offertes aux femmes enceintes atteintes de l'hépatite B. ISSUES: Les éléments évalués comprennent les seuils de traitement antiviral contre le VHB pour la prévention de la transmission périnatale et pour les interventions effractives durant la grossesse pour les femmes atteintes de l'hépatite B. RéSULTATS: Nous avons recherché dans MEDLINE, Embase et CINAHL des articles en anglais sur les sujets liés à l'infection par le VHB, à la grossesse et à la transmission périnatale publiés de 1966 à mars 2016. Nous n'avons tenu compte que des résultats qui proviennent de revues systématiques, d'essais contrôlés aléatoires ou d'essais cliniques contrôlés et d'études d'observation. Nous avons également étudié d'autres articles (non publiés) trouvés sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes connexes, dans des collections de directives cliniques et dans des registres d'essais cliniques, et obtenus auprès d'associations nationales et internationales de médecins spécialistes. MéTHODES DE VALIDATION: La qualité des résultats a été évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau 1). Les recommandations pour la pratique sont classées selon la méthode décrite dans ce rapport. MISE à JOUR DE DIRECTIVES CLINIQUES: La directive clinique sera évaluée cinq ans après sa publication afin de déterminer si une mise à jour est nécessaire. Cependant, si de nouvelles données probantes importantes sont publiées avant la fin du cycle de cinq ans, le processus peut être accéléré pour mettre à jour rapidement certaines recommandations. PARRAIN: La présente directive clinique a été élaborée à l'aide de ressources financées par la Société des obstétriciens et gynécologues du Canada. RECOMMANDATIONS.

No. 342-Hepatitis B and Pregnancy.

OBJECTIVE: To review the epidemiology, natural history, evaluation, and treatment of hepatitis B virus (HBV) infection during pregnancy. This will aid obstetric care providers in counseling their patients regarding perinatal risks and management options available to pregnant women with hepatitis B. OUTCOMES: Outcomes evaluated include thresholds for HBV anti-viral treatment for prevention of perinatal transmission and for invasive procedures during pregnancy for women with hepatitis B infection. EVIDENCE: Medline, EMBASE, and CINAHL were searched for articles in English on subjects related to HBV infection, pregnancy, and perinatal transmission from 1966 to March 2016. Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. Other (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical speciality societies. VALIDATION METHODS: The quality of the evidence is rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Recommendations for practice are ranked according to the method described in this Report. GUIDELINE UPDATE: The guideline will be reviewed 5 years after publication to decide if an update is required. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations. SPONSORS: This guideline was developed with resources funded by the Society of Obstetricians and Gynaecologists of Canada.

Post-Caesarean Section Surgical Site Infection Surveillance Using an Online Database and Mobile Phone Technology.

BACKGROUND: Obstetric surgical site infections (SSIs) are common and expensive to the health care system but remain under reported given shorter postoperative hospital stays and suboptimal post-discharge surveillance systems. SSIs, for the purpose of this paper, are defined according to the Center for Disease Control and Prevention (1999) as infection incurring within 30 days of the operative procedure (in this case, Caesarean section [CS]). PRIMARY OBJECTIVE: Demonstrate the feasibility of real-life use of a patient driven SSIs post-discharge surveillance system consisting of an online database and mobile phone technology (surgical mobile app - how2trak) among women undergoing CS in a Canadian urban centre. SECONDARY OBJECTIVE: Estimate the rate of SSIs and associated predisposing factors. METHODS: Prospective cohort of consecutive women delivering by CS at one urban Canadian hospital. Using surgical mobile app-how2trak-predetermined demographics, comorbidities, procedure characteristics, and self-reported symptoms and signs of infection were collected and linked to patients' incision self-portraits (photos) on postpartum days 3, 7, 10, and 30. RESULTS: A total of 105 patients were enrolled over a 5-month period. Mean age was 31 years, 13% were diabetic, and most were at low risk of surgical complications. Forty-six percent of surgeries were emergency CSs, and 104/105 received antibiotic prophylaxis. Forty-five percent of patients (47/105) submitted at least one photo, and among those, one surgical site infection was detected by photo appearance and self-reported symptoms by postpartum day 10. The majority of patients whom uploaded photos did so multiple times and 43% of them submitted photos up to day 30. Patients with either a diagnosis of diabetes or self-reported Asian ethnicity were less likely to submit photos. CONCLUSIONS: Post-discharge surveillance for CS-related SSIs using surgical mobile app how2trak is feasible and deserves further study in the post-discharge setting.

Cost-effectiveness of quantitative hepatitis B virus surface antigen testing in pregnancy in predicting vertical transmission risk.

BACKGROUND & AIMS: Vertical transmission of hepatitis B virus (HBV) can occur despite immunoprophylaxis in mothers with high HBV DNA levels (>5-7 log10 IU/ml). Quantitative hepatitis B surface antigen (qHBsAg) testing could be used as a surrogate marker to identify high viral load carriers, but there is limited data in pregnancy. We conducted a prospective observational study to determine the cost-effectiveness and utility of qHBsAg as a valid surrogate marker of HBV DNA. METHODS: Pregnant patients with chronic hepatitis B were recruited from a tertiary referral centre. HBV DNA levels and qHBsAg were assessed in the second to third trimester. Statistical analysis was performed by Spearman's rank correlation and student's t-test. The cost-effectiveness of qHBsAg as compared to HBV DNA testing was calculated. RESULTS: Ninety nine women with 103 pregnancies, median age 32 years, 65% Asian, 23% African and 12% other [Hispanic, Caucasian] were enrolled. Overall, 23% (23/99) were HBV e Ag (HBeAg)-positive. A significant correlation between qHBsAg and HBV DNA levels was noted in HBeAg-positive patients (r = 0.79, P < 0.05) but not in HBeAg-negative patients (r = 0.17, P = 0.06). In receiver operating characteristic analysis, the optimal qHBsAg cut-off values for predicting maternal viraemia associated with immunoprophylaxis failure (i.e., HBV DNA ≥7 log10 IU/ml) was 4.3 log10 IU/ml (accuracy 98.7%, sensitivity 94.7%, specificity 94.4%) (95% CI, 97-100%, P < 0.05). Use of HBV DNA as compared to qHBsAg costs approximately $20 000 more per infection prevented. CONCLUSION: In resource poor regions, qHBsAg could be used as a more cost-effective marker for high maternal viraemia, and indicate when anti-HBV nucleos/tide analogue therapy should be used to prevent HBV immunoprophylaxis failure.