COVID-19 vaccination before or during pregnancy results in high, sustained maternal neutralizing activity to SARS-CoV-2 wild-type and Delta/Omicron variants of concern, particularly following a booster dose or infection.

OBJECTIVES: To investigate multi-dose and timings of COVID-19 vaccines in preventing antenatal infection. DESIGN: Prospective observational study investigating primary vaccinations, boosters, antenatal COVID-19 infections, neutralizing antibody (Nab) durability, and cross-reactivity to Delta and Omicron variants of concern (VOCs). RESULTS: Ninety-eight patients completed primary vaccination prepregnancy (29.6%) and antenatally (63.3%), 24.2% of whom had antenatal COVID-19, while 7.1% were unvaccinated (28.6% had antenatal COVID-19). None had severe COVID-19. Prepregnancy vaccination resulted in vaccination-to-infection delay of 23.3 weeks, which extended to 45.2 weeks with a booster, compared to 16.9 weeks following antenatal vaccination (P < 0.001). Infections occurred at 26.2 weeks gestation in women vaccinated prepregnancy compared to 36.2 weeks gestation in those vaccinated during pregnancy (P < 0.007). The risk of COVID-19 infection was higher without antenatal vaccination (hazard ratio [HR] 14.6, P = 0.05) and after prepregnancy vaccination without a booster (HR 10.4, P = 0.002). Antenatal vaccinations initially led to high Nab levels, with mild waning but subsequent rebound. Significant Nab enhancement occurred with a third-trimester booster. Maternal-neonatal Nab transfer was efficient (transfer ratio >1), and cross-reactivity to VOCs was observed. CONCLUSION: Completing vaccination during any trimester delays COVID-19 infection and maintains effective neutralizing activity throughout pregnancy, with robust cross-reactivity to VOCs and efficient maternal-neonatal transfer.

Early initiation and regular breast milk expression reduces risk of lactogenesis II delay in at-risk Singaporean mothers in a randomised trial.

INTRODUCTION: Lactogenesis II (LaII) failure can be prevented in at-risk mothers with simple proactive interventions. In a randomised trial, we investigated the efficacy of early and regular breast milk expression in establishing LaII, using an electric double-breast pump. METHODS: Mothers with uncomplicated singleton deliveries were randomised to intervention (n = 31) or control (n = 29) groups. The former commenced breast milk expression with an electric pump within one hour of delivery and maintained regular expression with direct breastfeeding. Control mothers directly breastfed without regular pump expression. Expressed milk volumes were analysed for citrate, lactose, sodium and protein. RESULTS: Median time of LaII was Day 3 (interquartile range [IQR] 1 day) with intervention and on Day 4 (IQR 1 day) among controls (p = 0.03). Biochemical steady-state concentrations were achieved around early Day 4 (sodium, total protein) and Days 4-5 (citrate, lactose). Sodium, protein and lactose levels were similar in both groups over seven days, at 5.80 mM, 0.68 mM and -13.38 mM, respectively. Mean daily milk volume with intervention was 73.9 mL on Day 3 and 225.2 mL on Day 7, greater than controls (25.4 mL on Day 3 and 69.2 mL on Day 7; p < 0.2). Mean infant weights were similar on Day 8 at 3,477 g with intervention and 3,479 g among controls. CONCLUSION: LaII is established by postnatal Day 3 with early initiation of regular breast milk expression, a useful intervention for mothers at risk of early-onset breastfeeding failure.

Limited benefit of hepatitis B immunoglobulin prophylaxis in children of hepatitis B e antigen-negative mothers.

INTRODUCTION: In 2006, Singapore adopted the universal hepatitis B immunoglobulin (HBIg) policy. Since then, all infants of hepatitis B surface antigen (HBsAg)-positive mothers receive HBIg, irrespective of maternal hepatitis B e antigen (HBeAg) status. However, the benefits of HBIg for infants of HBeAg-negative mothers are unclear. We compared the vertical transmission rates among children of HBeAg-negative mothers who were given HBIg versus a retrospective cohort who were not given HBIg, to determine its protective effect. METHODS: This observational study involved pregnant HBsAg-positive women seen at National University Hospital, Singapore, between June 2009 and December 2013. If the infants of these mothers completed the recommended vaccination schedule, they were recruited into the study, along with their older siblings. Serological testing for the children was performed three months after completion of the last dose of vaccine, and hepatitis B virus (HBV) surface gene sequencing was carried out if HBV DNA was detected. RESULTS: A total of 111 infants and 47 siblings were recruited. 2 (1.5%) children were found to have vertical transmission despite receiving HBIg, while no incidences of vertical transmission were found among the historical controls who did not receive HBIg (p = 1.00). CONCLUSION: The overall effectiveness of the hepatitis B vaccination programme for children of HBsAg-positive mothers was high, regardless of HBIg administration. The addition of HBIg did not appear to confer additional benefits, in terms of vertical transmission rate, among infants born to HBeAg-negative mothers.

Hepatitis B immunoprophylaxis failure and the presence of hepatitis B surface gene mutants in the affected children.

Hepatitis B virus (HBV) infection is usually vertically transmitted from the mother to child during birth in Asian countries. Despite immunization, immunoprophylaxis failure is well-documented. The aim of the study was to study immunoprophylaxis failure rate in the cohort of infants delivered by chronic HBV-infected mothers and to determine risk factors for failure. This was an observational study involving chronic hepatitis B infected mothers seen at a tertiary care center in Singapore between June 2009 and December 2013. Infants born to these mothers were recruited after they had completed the recommended vaccination schedule. Serological testing for the children was performed 3 months after completion of the last dose of vaccine. HBV surface gene sequencing was carried out if HBV DNA was detectable in the children. Among the 161 mothers enrolled, most were HBeAg negative. HBeAg positive mothers were younger and had a significantly higher viral load (6.5 log) as compared to HBeAg negative mothers (1.35 log) (P < 0.001). Four children (2.6%) were found to have immunoprophylaxis failure. Two occurred in children delivered by mothers with extremely high viral load of more than 5 × 10(7) IU/ml. HBV surface gene mutations were detected in most children (3 out of 4) with immunoprophylaxis failure. The overall effectiveness of the hepatitis B vaccination program was high. High maternal viral load and presence of surface gene mutants may be potential contributors.

The influence of maternal ethnic group and diet on breast milk fatty acid composition.

INTRODUCTION: Breast milk fatty acids play a major role in infant development. However, no data have compared the breast milk composition of different ethnic groups living in the same environment. We aimed to (i) investigate breast milk fatty acid composition of three ethnic groups in Singapore and (ii) determine dietary fatty acid patterns in these groups and any association with breast milk fatty acid composition. MATERIALS AND METHODS: This was a prospective study conducted at a tertiary hospital in Singapore. Healthy pregnant women with the intention to breastfeed were recruited. Diet profile was studied using a standard validated 3-day food diary. Breast milk was collected from mothers at 1 to 2 weeks and 6 to 8 weeks postnatally. Agilent gas chromatograph (6870N) equipped with a mass spectrometer (5975) and an automatic liquid sampler (ALS) system with a split mode was used for analysis. RESULTS: Seventy-two breast milk samples were obtained from 52 subjects. Analysis showed that breast milk ETA (Eicosatetraenoic acid) and ETA:EA (Eicosatrienoic acid) ratio were significantly different among the races (P = 0.031 and P = 0.020), with ETA being the highest among Indians and the lowest among Malays. Docosahexaenoic acid was significantly higher among Chinese compared to Indians and Malays. No difference was demonstrated in n3 and n6 levels in the food diet analysis among the 3 ethnic groups. CONCLUSIONS: Differences exist in breast milk fatty acid composition in different ethnic groups in the same region, although no difference was demonstrated in the diet analysis. Factors other than maternal diet may play a role in breast milk fatty acid composition.

Noninvasive prenatal exclusion of haemoglobin Bart's using foetal DNA from maternal plasma.

OBJECTIVE: Prenatal diagnosis of alpha-thalassaemia requires invasive testing associated with a risk of miscarriage. Cell-free foetal DNA in maternal plasma presents an alternative source of foetal genetic material for noninvasive prenatal diagnosis. We aimed to exclude HbBart's noninvasively by detection of unaffected paternal alleles in maternal plasma using quantitative fluorescence PCR (QF-PCR). METHOD: Microsatellite markers (16PTEL05, 16PTEL06) within the breakpoint regions of -(SEA), -(FIL) and -(THAI) deletions were analysed using QF-PCR of maternal plasma from 30 families. In this blinded study, genotypes were confirmed using conventional PCR. Maternal plasma from two known cases of HbBart's were also analysed. RESULTS: HbBart's was excluded in 10 out of 30 (33.3%, 95% CI, 17.3-52.8%) mothers by identifying the presence of nondeleted paternally inherited fetal alleles; either only 16PTEL05 (n = 1) or only 16PTEL06 (n = 4), or both (n = 5), and confirmed through direct analysis of fetal DNA. Paternally inherited foetal alleles of 16PTEL05 and 16PTEL06 were not detected in maternal plasma of the two known HbBarts cases. False negatives were excluded with the detection of paternally inherited fetal control marker, D21S1270 in maternal plasma. CONCLUSION: We show proof-of-principle that such a test can accurately exclude HbBart's in the foetus by identifying the nondeleted paternally inherited fetal alleles in maternal plasma in one out of three pregnancies, avoiding invasive testing in these pregnancies.

Prenatal detection of isochromosome 21 by QF-PCR. A comparison between FISH and traditional karyotyping.

OBJECTIVE: To compare rapid aneuploidy diagnostic tests with traditional karyotyping in the prenatal detection of Down syndrome due to isochromosome 21. METHODS: Quantitative fluorescence PCR (QF-PCR) and fluorescent in situ hybridization (FISH) for chromosomes 13, 18, 21, X and Y were performed on uncultured amniotic fluid, followed by routine karyotyping. chromosomal and microsatellite analysis of peripheral blood from parents was also carried out. RESULTS: The QF-PCR screening showed a trisomic diallelic pattern for 5 of 6 markers spanning the long arm of chromosome 21. FISH showed 3 signals in the interphase cells for the region 21q22.13-q22 during LSI 21 probe mapping. Cultured amniotic fluid revealed an isochromosome 21 resulting in a 46,XX,i(21)(q10),+21 karyotype. Parental microsatellite analysis proved that the isochromosome was paternal in origin. CONCLUSION: The most informative analytical tool in this case appears to be QF-PCR, although a combination of QF-PCR and karyotyping provided the most evidence.

Antenatal education and postnatal support strategies for improving rates of exclusive breast feeding: randomised controlled trial.

OBJECTIVE: To investigate whether antenatal breast feeding education alone or postnatal lactation support alone improves rates of exclusive breast feeding compared with routine hospital care. DESIGN: Randomised controlled trial. SETTING: A tertiary hospital in Singapore. PARTICIPANTS: 450 women with uncomplicated pregnancies. MAIN OUTCOME MEASURES: Primary outcomes were rates of exclusive breast feeding at discharge from hospital and two weeks, six weeks, three months, and six months after delivery. Secondary outcomes were rates of any breast feeding. RESULTS: Compared with women who received routine care, women in the postnatal support group were more likely to breastfeed exclusively at two weeks (relative risk 1.82, 95% confidence interval 1.14 to 2.90), six weeks (1.85, 1.11 to 3.09), three months (1.87, 1.03 to 3.41), and six months (2.12, 1.03 to 4.37) postnatally. Women receiving antenatal education were more likely to breast feed exclusively at six weeks (1.73, 1.04 to 2.90), three months (1.92, 1.07 to 3.48), and six months (2.16, 1.05 to 4.43) postnatally. The numbers needed to treat to achieve one woman exclusively breast feeding at six months were 11 (6 to 80) for postnatal support and 10 (6 to 60) for antenatal education. Women who received postnatal support were more likely to exclusively or predominantly breast feed two weeks after delivery compared with women who received antenatal education (1.53, 1.01 to 2.31). The rate of any breastfeeding six weeks after delivery was also higher in the postnatal support group compared with women who received routine care (1.16, 1.02 to 1.31). CONCLUSIONS: Antenatal breast feeding education and postnatal lactation support, as single interventions based in hospital both significantly improve rates of exclusive breast feeding up to six months after delivery. Postnatal support was marginally more effective than antenatal education. TRIAL REGISTRATION: Clinical Trials NCT00270920 [ClinicalTrials.gov].

Differential recovery of membrane proteins after extraction by aqueous methanol and trifluoroethanol.

Cell membrane proteome analysis is limited by inherent membrane hydrophobicity. Conventional membrane protein extraction techniques use detergents, chaotropes and organic acids that require sample clean-up or pH adjustment, and are associated with significant sample loss. We extracted membrane proteins from red blood cells (RBCs) using methanol (MeOH), trifluoroethanol (TFE) and urea, and identified membrane proteins using 2-D LC coupled with MALDI-TOF/TOF-MS. We show that organic solvents MeOH- and TFE-based methods have membrane protein analysis efficiencies comparable to urea, and are complementary for the recovery of both hydrophilic and hydrophobic peptides. The mean grand average of hydropathicity (GRAVY) value of identified peptides from the TFE-based method (-0.107) was significantly higher than that of the MeOH-based method (-0.465) (p<0.001). Sequential and adjunctive use of the organic solvents MeOH and TFE increases the number of proteins identified, and the confidence of their identification. We show that this strategy is effective for shotgun membrane proteome analysis.

Simple antenatal preparation to improve breastfeeding practice: a randomized controlled trial.

OBJECTIVE: To address the impact of simple antenatal educational interventions on breastfeeding practice. METHODS: A randomized controlled trial was carried out in a tertiary referral center from May 2002 to December 2004. A random sample of eligible low-risk antenatal patients was recruited from clinics in the National University Hospital, Singapore. Group A received breastfeeding educational material and individual coaching from a lactation counselor. Group B received breastfeeding educational material with no counseling. Group C received routine antenatal care only. RESULTS: A total of 401 women were recruited. Mothers receiving individual counseling and educational material practiced exclusive and predominant breastfeeding more often than mothers receiving routine care alone at 3 months (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.2-5.4) and 6 months (OR 2.4, 95% CI 1.0-5.7) postpartum. More mothers practiced exclusive and predominant breastfeeding at 6 months among women receiving individual counseling compared with women exposed to educational material alone (OR 2.5, 95% CI 1.0-6.3). CONCLUSION: Where breastfeeding practices are suboptimal, simple one-encounter antenatal education and counseling significantly improve breastfeeding practice up to 3 months after delivery. Provision of printed or audiovisual educational material is not enough. Health care workers should make every effort to have one face-to-face encounter to discuss breastfeeding with expectant mothers before they deliver. CLINICAL TRIAL REGISTRATION: (www.ClinicalTrials.gov), NCT002770192 LEVEL OF EVIDENCE: I.

Microsatellite markers within --SEA breakpoints for prenatal diagnosis of HbBarts hydrops fetalis.

BACKGROUND: We sought to develop a rapid prenatal diagnostic test for simultaneous detection of HbBarts hydrops fetalis and exclusion of maternal contamination. METHODS: We developed a multiplex quantitative fluorescent PCR (QF-PCR) test that detects the presence/ absence of 2 microsatellite markers (16PTEL05/16PTEL06) located within breakpoints of the Southeast Asia ((-SEA)) deletion. HbBarts hydrops fetalis ((-SEA/-SEA)) is diagnosed by absence of both markers, and maternal contamination of fetal DNA is excluded by absence of noninherited maternal alleles. Fetal and parental DNA samples from 50 families were analyzed in a blinded clinical validation study, and QF-PCR results were compared with their respective molecular genotypes. RESULTS: The multiplex QF-PCR results included correct diagnoses of HbBarts hydrops fetalis in 11 of the fetuses tested, correct verification as unaffected in 20 fetuses, and correct identification as either carriers (alphaalpha/(-SEA)) or unaffected homozygotes in 18. Misidentification as unaffected occurred for 1 carrier. Sensitivity for diagnosis of HbBarts hydrops fetalis was 100% [lower 95% confidence interval, 76.2%], and specificity was 100% (lower 95% confidence interval, 92.6%). None of the samples tested showed any traces of noninherited maternal alleles; thus false-positives because of maternal contamination were eliminated. CONCLUSIONS: In this QF-PCR method, detection of maternally and paternally inherited fetal alleles allowed diagnosis of the double-deletion syndrome, and the ability to differentiate between these alleles allowed simultaneous exclusion of maternal contamination of the fetal genetic material. This novel strategy using cell-free fetal DNA in maternal plasma could form the basis for noninvasive testing for HbBarts hydrops fetalis.

Genome-wide gene expression profiling of human mast cells stimulated by IgE or FcepsilonRI-aggregation reveals a complex network of genes involved in inflammatory responses.

BACKGROUND: Mast cells are well established effectors of IgE-triggered allergic reactions and immune responses to parasitic infections. Recent studies indicate that mast cells may play roles in adaptive and innate immunity, suggesting an innovative view of the regulation of immune responses. Here, we profiled the transcriptome of human mast cells sensitized with IgE alone, or stimulated by FcepsilonRI aggregation. RESULTS: Our data show that among 8,793 genes examined, 559 genes are differentially regulated in stimulated mast cells when compared with resting/unstimulated mast cells. The major functional categories of upregulated genes include cytokines, chemokines, and other genes involved in innate and adaptive immune-responses. We observed the increased expression of over 63 gene-transcripts following IgE-sensitization alone. Our data was validated using Real-Time-PCR; ELISA and western blot. We confirmed that IgE alone does not trigger mast cell-immediate responses, such as calcium signals, degranulation or protein-phosphorylation. CONCLUSION: This report represents a substantial advance in our understanding of the genome wide effects triggered by "passive sensitization" or active stimulation of human mast cells, supporting mast cells' potential involvement in a wide range of inflammatory responses.

Cardiac time intervals of normal fetuses using noninvasive fetal electrocardiography.

OBJECTIVES: To evaluate the fetal cardiac time intervals from the longitudinal analysis of noninvasive fetal electrocardiography (fECG) in normal pregnancies. METHODS: One hundred singleton pregnancies were examined in this longitudinal study. Cardiac time intervals were derived from fetal electrocardiograms obtained noninvasively using three electrodes placed on the maternal abdomen. The variables measured included the durations of the P wave, PR interval, QRS complex, QT interval and T wave. RESULTS: Success rates for detecting the P, QRS and T waves were 74.6, 91.0 and 79.3%, respectively. Cardiac time intervals were significantly influenced by fetal age. The mean P-wave duration increased from 43.9 (18--22 weeks) to 52.9 ms (>/=37 weeks) (p < 0.001). PR intervals were 102.1 and 110.1 ms, for fetuses at 18 to 22 and >/=37 weeks (p < 0.001), respectively. QRS intervals were 47.2 and 52.6 ms (p < 0.001), while QT intervals were 224.0 and 242.7 ms (p < 0.001), at 18 to 22 and >/=37 weeks respectively. From 18 to 22 weeks to >/=37 weeks, QT(c) values increased from 343.8 to 367.7 ms (p < 0.001), while T-wave durations increased from 123.8 to 152.4 ms (p < 0.001). CONCLUSIONS: Serial noninvasive fECG of normal fetuses from 18 to 41 weeks of gestation show good success rates of fECG detection. Cardiac time intervals generally increased with increasing gestational age.