Post-partum maternal bradycardia: A case series and literature review.

Background: Unlike tachyarrhythmias, which are common in pregnancy, there is a paucity of data regarding maternal bradycardias. Our objective was to describe the characteristics, associated conditions, and prognosis of women who develop bradycardia post-partum. Method: We conducted a retrospective chart review of patients referred to the Obstetrical Medicine service at British Columbia Women's Hospital from January 2012 to May 2020 for post-partum maternal bradycardia. Results: Twenty-four patients with post-partum bradycardia were included (age 34.2 ± 4.8 years; heart rate 40.4 ± 8.1 beats per minute; blood pressure 131/72 mm Hg). Sinus bradycardia (79.2%) was the most common rhythm. Dyspnea (29.4%) and chest pain (23.5%) were common symptoms. Mean time to resolution of bradycardia was 3.6 ± 3.8 days. Associated conditions potentially explaining the bradycardia were preeclampsia (54.1%), underlying (16.7%), medications (8.3%), and neuraxial anesthesia (8.3%). Conclusions: Maternal bradycardia is an uncommon condition complicating the post-partum period, that is generally self-limiting, with the majority only require clinical observation.

Implementation of a home blood pressure monitoring program for the management of hypertensive disorders of pregnancy, an observational study in British Columbia, Canada.

Background: COVID-19 pandemic has influenced health care delivery. We conducted an observational study to understand how obstetric medicine (ObM) physicians utilized home blood pressure monitoring (HBPM) to manage hypertension in pregnancy. Methods: Pregnant participants with risk factors or diagnosis of hypertensive disorders of pregnancy (HDP) were enrolled, May 2020-December 2021, and provided with validated home blood pressure (BP) monitor. ObM physicians completed questionnaires to elicit how home BP readings were interpreted to manage HDP. Results: We enrolled 103 people: 44 antepartum patients (33.5 ± 5 years, gestational age of 24 ± 5 weeks); 59 postpartum patients (35 ± 6 years, enrolled 6 ± 4 days post-partum). ObM physicians used range of home BP readings (70%) for management of HDP. Conclusions: HBPM to manage HDP is acceptable and can be used to manage hypertension during pregnancy. Further studies are needed to assess the generalizability of our findings and the safety of HBPM reliance alone in management of HDP.

Investigation of factors associated with spontaneous preterm birth in pregnant women living with HIV.

OBJECTIVE: To investigate factors contributing to preterm birth (PTB), including cART use and clinical and social determinants of health, in women living with HIV (WLWH) from British Columbia, Canada. DESIGN: Retrospective observational cohort. METHODS: We investigated the effect of cART use and other clinical and demographic factors on spontaneous PTB (sPTB) rates (<37 weeks gestational age) among 631 singleton pregnancies between 1997 and 2018. Exposure to cART was modelled in comparison to no exposure, exposure in the first trimester, and between regimens. Differences in sPTB risk were estimated using time-dependent Cox's proportional hazards models. RESULTS: Overall, the sPTB rate was 16%. Cumulative cART use was associated with lower risk of PTB (Wald test P = 0.02; hazard ratio = 0.98, 95% CI = 0.96-0.99) and specific cART regimens were not associated with increased risk of sPTB. Exposure in the first trimester was not associated with sPTB and for each week of cART exposure, the risk of sPTB decreased by 2%. In a multivariable model, HIV viral load and substance use remained associated with risk of sPTB, but not cART exposure. CONCLUSION: The sPTB rate among pregnant WLWH was more than three times higher than in the general population. However, sPTB was not related specifically to use of cART; in fact, cART appeared to reduce the risk of sPTB. Uncontrolled HIV replication and substance use were associated with increased risk of sPTB among pregnant WLWH. This emphasizes the important role of prenatal care, access to cART, and smoking cessation and harm reduction to reduce the risk of sPTB in WLWH.

Evidence of Subclinical mtDNA Alterations in HIV-Infected Pregnant Women Receiving Combination Antiretroviral Therapy Compared to HIV-Negative Pregnant Women.

INTRODUCTION: Combination antiretroviral therapy (cART) can effectively prevent vertical transmission of HIV but there is potential risk of adverse maternal, foetal or infant effects. Specifically, the effect of cART use during pregnancy on mitochondrial DNA (mtDNA) content in HIV-positive (HIV+) women is unclear. We sought to characterize subclinical alterations in peripheral blood mtDNA levels in cART-treated HIV+ women during pregnancy and the postpartum period. METHODS: This prospective longitudinal observational cohort study enrolled both HIV+ and HIV-negative (HIV-) pregnant women. Clinical data and blood samples were collected at three time points in pregnancy (13-<23 weeks, 23-<30 weeks, 30-40 weeks), and at delivery and six weeks post-partum in HIV+ women. Peripheral blood mtDNA to nuclear DNA (nDNA) ratio was measured by qPCR. RESULTS: Over a four year period, 63 HIV+ and 42 HIV- women were enrolled. HIV+ women showed significantly lower mtDNA/nDNA ratios compared to HIV- women during pregnancy (p = 0.003), after controlling for platelet count and repeated measurements using a multivariable mixed-effects model. Ethnicity, gestational age (GA) and substance use were also significantly associated with mtDNA/nDNA ratio (p≤0.02). Among HIV+ women, higher CD4 nadir was associated with higher mtDNA/nDNA ratios (p<0.0001), and these ratio were significantly lower during pregnancy compared to the postpartum period (p<0.0001). CONCLUSIONS: In the context of this study, it was not possible to distinguish between mtDNA effects related to HIV infection versus cART therapy. Nevertheless, while mtDNA levels were relatively stable over time in both groups during pregnancy, they were significantly lower in HIV+ women compared to HIV- women. Although no immediate clinical impact was observed on maternal or infant health, lower maternal mtDNA levels may exert long-term effects on women and children and remain a concern. Improved knowledge of such subclinical alterations is another step toward optimizing the safety and efficacy of cART regimens during pregnancy.

Evaluation of an emergency prevention program for mother to child transmission of HIV in British Columbia.

INTRODUCTION: The objective of this study was to evaluate a province-wide program designed to identify HIV infection accurately and to prevent mother to child transmission among high-risk pregnant women of unknown serostatus. METHODS: Between 2000 and 2007, 347 high-risk women were identified through the Prevention of Mother to Child Transmission (PMTCT) program implemented in 27 hospitals across British Columbia. Rates of HIV transmission and details of the implementation of prophylaxis kits were assessed. RESULTS: Of the 346 high-risk mother-infant pairs identified and included in the provincial program, 35.4% of the mothers and 95.7% of infants received antiretroviral therapy for prevention of vertical transmission. Of 309 pairs who subsequently underwent HIV testing, five mothers were found to be HIV positive, an infection rate of 16.2/1000 in this cohort; the overall rate in BC is 0.68/1000 births. One of the five infants born to an HIV positive mother was infected with HIV. DISCUSSION: The program was successful in identifying a subgroup of pregnant women at increased risk of HIV infection; however, mother to child transmission occurred in one of five cases (20%). To reduce the risk of mother to child HIV transmission in BC to the lowest possible level, additional strategies such as increasing uptake of prenatal screening and point-of-care testing in labour and delivery may need to be explored.

The bacterial virulence factor NleA inhibits cellular protein secretion by disrupting mammalian COPII function.

Enterohemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) maintain an extracellular lifestyle and use a type III secretion system to translocate effector proteins into the host cytosol. These effectors manipulate host pathways to favor bacterial replication and survival. NleA is an EHEC/EPEC- and related species-specific translocated effector protein that is essential for bacterial virulence. However, the mechanism by which NleA impacts virulence remains undetermined. Here we demonstrate that NleA compromises the Sec23/24 complex, a component of the mammalian COPII protein coat that shapes intracellular protein transport vesicles, by directly binding Sec24. Expression of an NleA-GFP fusion protein reduces the efficiency of cellular secretion by 50%, and secretion is inhibited in EPEC-infected cells. Direct biochemical experiments show that NleA inhibits COPII-dependent protein export from the endoplasmic reticulum. Collectively, these findings indicate that disruption of COPII function in host cells contributes to the virulence of EPEC and EHEC.