Effect of Wearing a Face Mask on Hand-to-Face Contact by Children in a Simulated School Environment: The Back-to-School COVID-19 Simulation Randomized Clinical Trial

IMPORTANCE

Wearing a face mask in school can reduce SARS-CoV-2 transmission but it may also lead to increased hand-to-face contact, which in turn could increase infection risk through self-inoculation.

OBJECTIVE

To evaluate the effect of wearing a face mask on hand-to-face contact by children while at school.

DESIGN, SETTING, AND PARTICIPANTS

This prospective randomized clinical trial randomized students from junior kindergarten to grade 12 at 2 schools in Toronto, Ontario, Canada, during August 2020 in a 1:1 ratio to either a mask or control class during a 2-day school simulation. Classes were video recorded from 4 angles to accurately capture outcomes.

INTERVENTIONS

Participants in the mask arm were instructed to bring their own mask and wear it at all times. Students assigned to control classes were not required to mask at any time (grade 4 and lower) or in the classroom where physical distancing could be maintained (grade 5 and up).

MAIN OUTCOMES AND MEASURES

The primary outcome was the number of hand-to-face contacts per student per hour on day 2 of the simulation. Secondary outcomes included hand-to-mucosa contacts and hand-to-nonmucosa contacts. A mixed Poisson regression model was used to derive rate ratios (RRs), adjusted for age and sex with a random intercept for class with bootstrapped 95% CIs.

RESULTS

A total of 174 students underwent randomization and 171 students (mask group, 50.6% male; control group, 52.4% male) attended school on day 2. The rate of hand-to-face contacts did not differ significantly between the mask and the control groups (88.2 vs 88.7 events per student per hour; RR, 1.00; 95% CI, 0.78-1.28; P = >.99). When compared with the control group, the rate of hand-to-mucosa contacts was significantly lower in the mask group (RR, 0.12; 95% CI, 0.07-0.21), while the rate of hand-to-nonmucosa contacts was higher (RR, 1.40; 95% CI, 1.08-1.82).

CONCLUSIONS AND RELEVANCE

In this clinical trial of simulated school attendance, hand-to-face contacts did not differ among students required to wear face masks vs students not required to wear face masks; however, hand-to-mucosa contracts were lower in the face mask group. This suggests that mask wearing is unlikely to increase infection risk through self-inoculation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04531254.

Le retour en classe et le port du masque pendant la pandémie de COVID-19 : le point de vue des élèves d’après une étude de simulation scolaire

Objectifs

La présente étude s’est penchée sur le point de vue des enfants relativement au retour en classe après le confinement imposé par la pandémie, sur le port du masque en classe et sur la santé mentale des enfants et des parents pendant la pandémie.

Méthodologie

La présente étude transversale a fait partie d’un exercice de simulation scolaire de deux jours au cours duquel les élèves ont été répartis au hasard entre diverses recommandations sur le port du masque. Au moyen d’analyses régression multiple, les chercheurs ont analysé le compte rendu des parents sur la santé mentale et, après la simulation, celui des élèves sur l’anxiété liée à la COVID-19 et le port du masque. Les élèves plus âgés ont participé à des groupes de travail semi-structurés pour compléter les données du questionnaire.

Résultats

Sur les 190 élèves de la présente étude, 31 % ne dépassaient pas la quatrième année et 95 % avaient hâte de rentrer en classe. La plus grande anxiété des parents ou des proches (β= 0,67; p <0,001) et leur niveau de scolarité plus bas (β=1,86; p <0,002) étaient prédicteurs d’une plus grande anxiété des enfants à l’égard de la COVID-19. Les élèves plus âgés étaient plus susceptibles de trouver le port du masque nuisible aux interactions avec leurs camarades que les plus jeunes (χ2[1]=31,16; p <0,001) et pour leur capacité à comprendre l’enseignant (χ2[1]=13,97; p <0,001). Les élèves du groupe sans masque étaient plus susceptibles de craindre de contracter la COVID-19 à l’école (χ2[1]=10,07; p <0,05) que ceux du groupe qui le portaient, et d’anticiper éprouver de la difficulté à le porter (χ2[1]=18,95; p <0,001).

Conclusions

Chez les enfants anxieux à cause de la COVID-19, l’anxiété des parents et l’information sur la COVID-19 pourraient être des cibles d’intervention. De futures recherches devraient porter sur les effets de la mise en œuvre prolongée de mesures sanitaires d’atténuation des risques sur la réussite scolaire et la santé mentale des enfants.

Return to school and mask-wearing in class during the COVID-19 pandemic: Student perspectives from a school simulation study

Objectives

This study examined children’s perspectives about returning to in-person school following lockdown due to the pandemic and about mask-wearing in class, as well as the mental health of children and parents during the pandemic.

Methods

This cross-sectional study was part of a 2-day school simulation exercise that randomized students to different masking recommendations. Parent-report of mental health and post-simulation child-report of COVID-19-related anxiety and mask-wearing were analyzed using descriptive and multiple regression analyses. Semi-structured focus groups were conducted with older students to supplement questionnaire data.

Results

Of 190 students in this study, 31% were in grade 4 or lower 95% looked forward to returning to in-person school. Greater child anxiety about COVID-19 was predicted by increased parent/caregiver anxiety (β=0.67; P<0.001), and lower parental educational attainment (β=1.86; P<0.002). Older students were more likely than younger students to report that mask-wearing interfered with their abilities to interact with peers (χ²(1)=31.16; P<0.001) and understand the teacher (χ²(1)=13.97; P<0.001). Students in the group that did not require masks were more likely than students in the masking group to report worries about contracting COVID-19 at school (χ²(1)=10.07; P<0.05), and anticipated difficulty wearing a mask (χ²(1)=18.95; P<0.001).

Conclusions

For children anxious about COVID-19, parental anxiety and education about COVID-19 may be targets for intervention. Future research should examine the impact of prolonged implementation of public health mitigation strategies in school on academic achievement and children’s mental health.

Fetoscopic Laser Ablation for Twin-to-Twin Transfusion Syndrome: A 15-year Review of Perinatal Survival

Objective Twin to twin transfusion syndrome (TTTS) complicates 5-15% of monochorionic twin pregnancies and untreated is associated with a 90% mortality rate. The aim was to present the perinatal survival of patients with TTTS treated with laser ablation, by a national fetal medicine team. Methods This was a review of all cases of TTTS treated with fetoscopic laser ablation performed from March 2006 through to December 2020. All patients treated with fetoscopic laser were identified from the hospital database. The perinatal outcomes for the overall cohort and the individual Quintero stages were determined. Results A total of 155 cases of TTTS underwent fetoscopic laser ablation during the study period. The median gestational age at diagnosis was 19+1 weeks, with a mean growth discordance of 23.6%. The Quintero stage at diagnosis was: Stage 1 6.5% (10/155), Stage 2 49% (76/155), Stage 3 38.7% (60/155), Stage 4 5.8% (9/155). There was at least one survivor in 83.2% (129/155) of pregnancies, with dual survival in 52.9% (82/155). An increase in the rate of any survivor was observed from 75% (2006-2014) to 94% (2014-2020) (p<0.05). Dual survival decreased with increasing Quintero Stage (p<0.05). 80.6% (125/155) of pregnancies delivered prior to 34+6 weeks gestation. Conclusion Fetoscopic laser ablation is the recommended first line treatment for severe TTTS. We observed a survival rate of at least one twin in 83.2% pregnancies which is comparable to internationally published data on single-centre outcomes.

Annual prevalence estimation of lymphatic malformation with a cutaneous component: observational study of a national representative sample of physicians

Background

Lymphatic malformations (LMs) represent a potentially life-threatening, rare disease of the lymphatic system characterized by development of abnormal vessels, outpouchings, or cysts filled with lymphatic fluid. There are three morphologic types of LMs based on the size of the individual cysts: macrocystic (typically > 2 cm), microcystic (generally < 2 cm), and mixed (includes aspects of both). Macrocystic LMs typically exist beneath the skin and often can involve vascular components and/or organs. Microcystic LMs often have a cutaneous component and clinically present with lymphorrhea, bleeding, pain, itching, malodor, and functional deficits. There are no treatments approved by the US Food and Drug Administration (FDA) for either macrocystic or microcystic lymphatic malformations. The totality of the epidemiologic literature for LM is limited to the incidence of the disease among various birth cohorts. This is the first nationally representative study to estimate the national managed prevalence for patients with microcystic LM or combined LM with a cutaneous component annually across physician specialties likely to manage this condition. We conducted a retrospective observational survey of a nationally representative sample of patient-care physicians in the United States most likely to manage lymphatic malformations with a cutaneous component (LMC). Once recruited, target physicians participated via an electronic questionnaire. We weighted study physician self-estimates of the number of LMC patients treated in the past 12 months to reflect the specialists’ corresponding proportion in the national universe. All patient information was anonymous; no personally identifiable information was collected.

Results

Of the 420 physicians who visited the study website, 316 agreed to be screened and to participate (75.2% participation rate). Our survey results indicated the estimated number of unique annually managed LMC patients by target specialists is 79,920 (CI 66,600–93,250). This number corresponds to managed prevalence of 24.1 LMC patients per 100,000 population (CI 19.6/100,000–28.4/100,000).

Conclusions

The study indicates that while rare, LMC affects a substantial number of people in the US (79,920) who are being managed by one or more specialists. By better understanding the prevalence of people living with LMC who require treatment, efforts to both increase disease awareness and to identify underserved populations in need of potential new treatments can be better focused.

Impact of COVID-19 Public Health Protocols on Teachers Instructing Children and Adolescents During an In-Person Simulation

Objective

As a result of the COVID-19 pandemic, public health agencies and school boards across Canada enacted new protocols, including face masks, physical distancing and enhanced hygiene, to support the safe reopening of in-person school. This study explored the experiences and perceptions of teachers instructing children and adolescents in person during a two-day school simulation.

Method

This study was part of a large school simulation exercise conducted in Toronto, Ontario. Kindergarten to grade 12 teachers taught in classrooms with either masked students, or students who were un-masked or only masked when physical distancing was not possible. A qualitative descriptive phenomenology approach was utilized, and data were collected via virtual focus groups. Qualitative data analysis involved multiple rounds of inductive coding to generate themes.

Results

The sample included 14 teachers (92.9% female; 85.7% White), with a median of 9.5 years teaching experience. Three primary themes emerged: 1) learning to navigate public health measures, 2) needing to adapt teaching strategies and 3) striving to manage conflicting priorities. The majority of teachers reported that mask-wearing and physical distancing impacted their classroom teaching, communication and connection with students.

Conclusions

As schools transition to in-person instruction, teachers will be required to play dual roles in education and public health, with implications on safety, teaching and professional identity. Public health agencies and school boards are encouraged to engage teachers in ongoing conversations regarding in-person school planning and operations. Furthermore, evidence-based interventions, including increased teaching development programs, are recommended to support teachers during the COVID-19 pandemic.

Regional binding of tau and amyloid PET tracers in Down syndrome autopsy brain tissue

INTRODUCTION

Tau pathology is a major age-related event in Down syndrome with Alzheimer's disease (DS-AD). Although recently, several different Tau PET tracers have been developed as biomarkers for AD, these tracers showed different binding properties in Alzheimer disease and other non-AD tauopathies. They have not been yet investigated in tissue obtained postmortem for DS-AD cases. Here, we evaluated the binding characteristics of two Tau PET tracers (³H-MK6240 and ³H-THK5117) and one amyloid (³H-PIB) ligand in the medial frontal gyrus (MFG) and hippocampus (HIPP) in tissue from adults with DS-AD and DS cases with mild cognitive impairment (MCI) compared to sporadic AD.

METHODS

Tau and amyloid autoradiography were performed on paraffin-embedded sections. To confirm respective ligand targets, adjacent sections were immunoreacted for phospho-Tau (AT8) and stained for amyloid staining using Amylo-Glo.

RESULTS

The two Tau tracers showed a significant correlation with each other and with AT8, suggesting that both tracers were binding to Tau deposits. ³H-MK6240 Tau binding correlated with AT8 immunostaining but to a lesser degree than the ³H-THK5117 tracer, suggesting differences in binding sites between the two Tau tracers. ³H-THK5117, ³H-MK6240 and ³H-PIB displayed dense laminar binding in the HIPP and MFG in adult DS brains. A regional difference in Tau binding between adult DS and AD was observed suggesting differential regional Tau deposition in adult DS compared to AD, with higher THK binding density in the MFG in adult with DS compared to AD. No significant correlation was found between ³H-PIB and Amylo-Glo staining in adult DS brains suggesting that the amyloid PIB tracer binds to additional sites.

CONCLUSIONS

This study provides new insights into the regional binding distribution of a first-generation and a second-generation Tau tracer in limbic and neocortical regions in adults with DS, as well as regional differences in Tau binding in adult with DS vs. those with AD. These findings provide new information about the binding properties of two Tau radiotracers for the detection of Tau pathology in adults with DS in vivo and provide valuable data regarding Tau vs. amyloid binding in adult DS compared to AD.

A Retrospective Analysis of Joint Cultures: Only Time Will Tell (Or Will It?)

Introduction/Objective

Multiple textbooks and guidelines, including CLSI, recommend holding joint cultures for 14 days. This prevents false negative results from “slower growers” which include Actinomyces species and Propionibacterium acnes. Holding of these cultures can be a burden for small microbiology labs.

Methods

A retrospective analysis of three years of joint cultures held for 14 days was reviewed. The length of time for the culture to turn positive and the organism that grew was noted.

Results

A total of 67 positive joint cultures were evaluated, which covered a period of 3 years at our institution. Of these, only 1 culture turned positive following day 5 (Propionibacterium acnes grew on day 6). The average time to positive for Propionibacterium acnes was 4 days. In comparison, the average growth time for Staphylococcus aureus and Proteus was 1 day, Pseudomonas aeruginosa was 1.2 days, all Streptococcus species was 2.4 days and Staphylococcus epidermidis was 2.7 days. No cultures grew Actinomyces during our study.

Conclusion

The consequences of missing a positive culture can be grave. In general, culture media has improved and provided increased growth rates. With resources becoming more limited, it may be time to revisit guidelines. This study is too small to be conclusive; a larger study may provide confirmation of the findings.

Socioeconomic status amplifies genetic effects in middle childhood in a large German twin sample

The Scarr-Rowe hypothesis predicts that the heritability of cognitive abilities is higher in more privileged socioeconomic conditions, meaning that genetic potential can be more fully expressed in environments characterized by high socioeconomic status (SES) compared to low SES. This gene × SES interaction, however, has been replicated mostly in the United States, but not in other Western nations like the United Kingdom. In the current study, we tested the interaction between childhood SES and the heritability of cognitive ability in 3,074 German twin pairs comprising three age cohorts at different developmental stages (mean ages of 11, 17, and 23 years). Higher SES was associated with significantly higher mean cognitive ability scores in the two younger cohorts, with reduced variances at higher SES levels. Results further support the Scarr-Rowe hypothesis in middle childhood, and to some degree in adolescence, but not in adulthood. This indicates that the role of family SES as a moderator of the heritability of cognitive ability changes as children grow older. Moreover, children's shared experiences appear to be explain more variance in cognitive ability at the lower end of the SES distribution in middle childhood and adolescence.

A Psychosexual Rehabilitation Booklet Increases Vaginal Dilator Adherence and Knowledge in Women Undergoing Pelvic Radiation Therapy for Gynaecological or Anorectal Cancer: A Randomised Controlled Trial

AIMS

Women treated with pelvic radiation therapy (PRT) for gynaecological or anorectal cancer report a high number of sexual problems and unmet post-treatment psychosexual information needs. Currently, there is suboptimal adherence to recommended rehabilitation aids, such as vaginal dilators, and a paucity of resources to facilitate post-radiation rehabilitation and reduce distress in this population. This randomised controlled trial aimed to evaluate the effectiveness of a study-developed psychosexual rehabilitation booklet in this setting.

MATERIALS AND METHODS

Eighty-two women scheduled for PRT to treat gynaecological/anorectal cancer were randomised to receive the intervention booklet (n = 44) or standard information materials (n = 38). Self-report questionnaires administered at pre-treatment baseline and at 3, 6 and 12 months post-treatment assessed adherence with rehabilitation aids, booklet knowledge, anxiety, depression and sexual functioning/satisfaction.

RESULTS

Dilator adherence and booklet knowledge were significantly higher in the intervention group than in the control group (averaged over time points), with scores significantly increasing over time. Younger age and gynaecological cancer were significant predictors of greater dilator adherence. No significant group differences were found on psychological and sexual measures.

CONCLUSIONS

The psychosexual rehabilitation booklet was effective in educating women with gynaecological and anorectal cancers about PRT-related psychosexual side-effects and rehabilitation options, as well as promoting uptake of vaginal dilator use. Future research should elucidate the effectiveness of this booklet in women with greater psychological and sexual functioning needs.

The cost of Mycobacterium avium complex lung disease in Canada, France, Germany, and the United Kingdom: a nationally representative observational study

Background

Management of nontuberculous mycobacterial lung disease (NTMLD) consists of a long-term multi-drug antibiotic regimen, yet many patients do not achieve culture conversion. We estimated the NTMLD-related direct medical costs in Canada, France, Germany, and the United Kingdom (UK) among refractory patients who were infected with Mycobacterium avium complex (MAC), without concomitant cystic fibrosis, tuberculosis, or HIV.

Methods

We conducted a retrospective observational physician survey of nationally representative samples. The survey captured anonymized information about patients’ treatment histories for NTMLD-related health care resource utilization over a 24-month period. We summarized NTMLD-related resource use and estimated the total economic burden, from each country’s health care payer perspective.

Results

In total, 59 physicians provided data on 157 patients. The average person time observed during the 24-month period was 1.7 years (SD: 0.4); 17% of patients died by the end of the study period. The major components of NTMLD-related direct medical costs among refractory patients were hospitalizations (varying from 29% of total annual costs in the UK to 69% in France), outpatient visits (8% in Canada to 51% in the UK), and outpatient testing such as post-diagnostic sputum testing, bronchial wash/lavage, spirometry, biopsies, imaging, and electrocardiograms (5% in France to 35% in Canada). In this patient cohort, the average direct medical costs per person-year, in local currencies, were approximately $16,200 (Canada), €11,600 (Germany), €17,900 (France) and £9,700 (UK).

Conclusions

Based on this study’s findings, we conclude that managing patients with refractory NTMLD caused by MAC is associated with a substantial economic burden.

Electronic supplementary material

The online version of this article (10.1186/s12913-018-3489-8) contains supplementary material, which is available to authorized users.

The repeatability of the abbreviated (4-h) Oral Fat Tolerance Test and influence of prior acute aerobic exercise

PURPOSE

The Oral Fat Tolerance Test (OFTT) is regarded as a repeatable measure used to assess postprandial triglyceride (TAG) levels, with higher levels observed in cardio-metabolic disorders. Acute aerobic exercise intervention before OFTT reduces the TAG response, but the repeatability of this effect is unknown. The aim of this study was to determine the repeatability of the abbreviated 4-h OFTT with and without immediate prior aerobic exercise.

METHODS

On four separate days, healthy adult male participants underwent two 4-h OFTT (n = 10) and another two 4-h OFTT with 1-h of standardised moderate intensity aerobic exercise performed immediately before meal ingestion (n = 11). The OFTT meal composition included 75.4 g total fat, 21.7 g carbohydrate and 13.7 g protein. Venous blood was sampled at baseline and hourly up to 4 h after the OFTT meal ingestion, and TAG area under the curve (AUC) was calculated.

RESULTS

Nonparametric Bland-Altman analysis of 4-h TAG AUC revealed that 9 of 10 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT. By contrast, two of 11 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT undertaken with 1-h prior aerobic exercise.

CONCLUSIONS

The 4-h OFTT is a repeatable test of postprandial TAG responses in healthy men. However, aerobic exercise performed immediately before OFTT considerably increases the variability of TAG AUC. These findings have implications for interpretation of research studies investigating exercise intervention performed immediately before OFTT. Future studies should also investigate the repeatability of exercise performed 8-24 h before OFTT.

Estimated peak functional capacity: an accurate method for assessing change in peak oxygen consumption after cardiac rehabilitation?

OBJECTIVE

Cardiopulmonary exercise testing (CPET) is the 'gold standard' method of determining VO_2peak . When CPET is unavailable, VO_2peak may be estimated from treadmill or cycle ergometer workloads and expressed as estimated metabolic equivalents (METs). Cardiac rehabilitation (CR) programmes use estimated VO_2peak (METs) to report changes in cardiorespiratory fitness (CRF). However, the accuracy of determining changes in VO_2peak based on estimated functional capacity is not known.

METHODS

A total of 27 patients with coronary heart disease (88·9% male; age 59·5 ± 10·0 years, body mass index 29·6 ± 3·8 kg m^-2 ) performed maximal CPET before and after an exercise-based CR intervention. VO_2peak was directly determined using ventilatory gas exchange data and was also estimated using the American College of Sports Medicine (ACSM) leg cycling equation. Agreement between changes in directly determined VO_2peak and estimated VO_2peak was evaluated using Bland-Altman limits of agreement (LoA) and intraclass correlation coefficients.

RESULTS

Directly determined VO_2peak did not increase following CR (0·5 ml kg^-1 min^-1 (2·7%); P = 0·332). Estimated VO_2peak increased significantly (0·4 METs; 1·4 ml kg^-1  min^-1 ; 6·7%; P = 0·006). The mean bias for estimated VO_2peak versus directly determined VO_2peak was 0·7 ml kg^-1  min^-1 (LoA -4·7 to 5·9 ml  kg^-1  min^-1 ). Aerobic efficiency (ΔVO₂ /ΔWR slope) was significantly associated with estimated VO_2peak measurement error.

CONCLUSION

Change in estimated VO_2peak derived from the ACSM leg cycling equation is not an accurate surrogate for directly determined changes in VO_2peak . Our findings show poor agreement between estimates of VO_2peak and directly determined VO_2peak . Applying estimates of VO_2peak to determine CRF change may over-estimate the efficacy of CR and lead to a different interpretation of study findings.

Using fiberoptic endoscopic evaluation of swallowing to detect laryngeal penetration and aspiration in infants in the neonatal intensive care unit

OBJECTIVE

To evaluate the safety of fiberoptic endoscopic evaluation of swallowing (FEES) and the reliability of both FEES and a videofluoroscopic swallowing study (VFSS) in identifying laryngeal penetration and tracheal aspiration in infants under 3 months old in the neonatal intensive care unit (NICU).

STUDY DESIGN

Twenty-five infants at least 37 weeks postmenstrual age suspected of aspirating were assessed with FEES and VFSS. Complications, autonomic instability and vital signs before endoscope insertion and following FEES were documented. Blinded video recordings were coded by two reviewers to determine reliability.

RESULTS

We found no major complications or significant differences between FEES prefeeding and postfeeding vital signs, including respiratory rate, heart rate or oxygen saturation. FEES interrater reliability was 80% for both penetration and aspiration, compared with 87 and 90%, respectively, for VFSS.

CONCLUSION

FEES is safe and reliable in assessing laryngeal penetration and tracheal aspiration in NICU infants.

We think you can dance! A pilot randomised controlled trial of dance for nursing home residents with moderate to severe dementia

OBJECTIVES

To evaluate the feasibility of a dance program for people with moderate to severe dementia living in nursing homeswith regards to recruitment and retention, assessment tools, intervention safety, attendance and engagement.

DESIGN

Pilot randomised controlled trial with assessments at weeks 0, 16 and 32.

SETTING

A nursing home in Sydney, Australia.

INTERVENTIONS

Experienced dance teachers conducted dance groups (intervention) or music appreciation and socialisation groups (control) for 45min, three times a week for 16 weeks.

MAIN OUTCOME MEASURES

Descriptive statistics for recruitment and retention, adverse events and attendance and engagement.

RESULTS

Recruitment was smooth, attrition was17% over 32 weeks. Engagement during the sessions was high, and no serious falls or behavioural incidents occurred. Average attendance was poorer than anticipated for dance groups (67%) in comparison to music groups (89%). A ceiling effect on the Severe Impairment Battery and the logistical challenges of the Clinical Global Impression of Change meant they may not be optimal tools.

CONCLUSIONS

It is feasible to conduct a study of group dance for people with moderate to severe dementia in residential care. Choice of attention control condition should be reconsidered.

Mode of delivery in pregnancies complicated by major fetal congenital heart disease: a retrospective cohort study

OBJECTIVE

To determine the mode of delivery in pregnancies complicated by complex fetal congenital heart disease (CHD).

STUDY DESIGN

Five-year retrospective cohort study at a tertiary fetal medicine center (2007 to 2011). Cases of complex fetal CHD (n=126) were compared with 45 069 non-anomalous singleton infants ⩾500 g to determine rates of emergency intrapartum cesarean section (CS), preterm delivery and induction of labor.

RESULT

Intrapartum CS is significantly higher in fetal CHD than non-anomalous controls (21% vs 13.5%, odds ratio (OR) 1.7, 95% confidence interval (CI): 1.0 to 2.7; P=0.035), predominantly related to CS for non-reassuring fetal status (OR 2.2, 95% CI: 1.1 to 4.1; P=0.022). Although fetal CHD did not increase emergency CS rates in nulliparous women, CS was significantly increased in multiparous pregnancies (OR 2.4, 95% CI: 1.8 to 4.6; P=0.014). Rates of preterm delivery (OR 3.4, 95% CI: 2.0 to 5.4; P<0.0001) and induction of labor (OR 1.9, 95% CI: 1.3 to 2.9; P=0.001) were higher in the CHD cases.

CONCLUSION

Emergency CS is increased in fetal CHD, attributed to a higher rate of CS for non-reassuring fetal status and seen mostly in multiparous women.

Reassessing critical maternal antibody threshold in RhD alloimmunization: a 16-year retrospective cohort study

OBJECTIVE

To determine the critical maternal antibody threshold for specialist referral in cases of RhD alloimmunization.

METHODS

This was a retrospective cohort study, covering a 16-year period at the national tertiary fetal medicine center for management of alloimmunization. Data concerning RhD alloimmunized pregnant women were extracted from an institutional database and maternal anti-D antibody levels were cross-checked with the national reference laboratory. Fetal hemoglobin (Hb) levels were determined only at the first intrauterine transfusion (IUT) and were compared with the pretransfusion maternal anti-D antibody level (IU/mL). Sensitivity, specificity and positive and negative predictive values of maternal antibody thresholds for detecting moderate to severe (Hb ≤ 0.64MoM) fetal anemia were calculated.

RESULTS

Between 1996 and 2011, 66 women underwent a first IUT for RhD alloimmunization at our institution. The highest serum anti-D antibody level was extracted for 208 RhD alloimmunized women who did not require IUT during the last 10 years of the study period. The traditional maternal antibody threshold of > 15 IU/mL failed to detect 20% of cases of moderate to severe fetal anemia. The ≥ 4 IU/mL threshold had 100% sensitivity but a 45% false-positive rate. The optimal anti-D antibody threshold for specialist referral in our population was ≥ 6 IU/mL; at this level, no case of moderate to severe anemia was missed and specificity was 61%. Use of this threshold would have eliminated 10% of referrals to our fetal medicine unit without compromising fetal outcomes.

CONCLUSIONS

Setting the critical maternal RhD antibody level at >15 IU/mL does not provide sufficient sensitivity. The lower threshold of ≥ 4 IU/mL, though sensitive, is associated with a 45% false-positive rate. In our population, a threshold of ≥ 6 IU/mL minimizes false-positive referrals while maintaining 100% sensitivity for moderate to severe fetal anemia.