Prolonged operative time of cesarean is a risk marker for subsequent cesarean maternal complications.

PURPOSE: Prolonged cesarean operative time (OT) is a well-established proxy for post-operative maternal complications. We aimed to study whether prolonged OT may serve as a proxy for maternal complications in the subsequent cesarean delivery. METHODS: A retrospective cohort study of women who underwent cesarean delivery between 2005 and 2019. Parturients who had two subsequent cesarean deliveries were included and those with Placenta Accreta Syndrome (PAS) were excluded. Prolonged operative time was defined as the duration of cesarean delivery above 60 min. Univariate analyses were followed by multivariate analysis (adjusted Odds Ratio (aORs); [95% Confidence Interval]). RESULTS: A total of 5163 women met the inclusion and exclusion criteria of which 360 (7%) had prolonged operative time. Prolonged operative time of a cesarean section in the index pregnancy was significantly associated in the subsequent cesarean delivery with the following: Prolonged operative time, intra-operative blood loss > 1000 ml, postpartum hemorrhage, blood products transfusion, injuries to the urinary system in the subsequent delivery, and hysterectomy. Multivariate analysis revealed that prolonged OT in the index delivery was associated with composite adverse maternal outcome (aOR 1.46 [1.09-1.95]; P = 0.01) and blood products transfusion (aOR 2.93 [1.90-4.52]; P < 0.01) in the subsequent delivery. CONCLUSION: Prolonged operative may serve as a proxy for adverse maternal outcomes, mostly blood products transfusion, in the subsequent cesarean delivery among women undergoing repeat cesarean delivery.

Perfect Chirality with Imperfect Polarization.

Unidirectional (chiral) emission of light from a circular dipole emitter into a waveguide is only possible at points of perfect circular polarization (C points), with elliptical polarizations yielding a lower directional contrast. However, there is no need to restrict engineered systems to circular dipoles, and with an appropriate choice of dipole unidirectional emission is possible for any elliptical polarization. Using elliptical dipoles, rather than circular, typically increases the size of the area suitable for chiral interactions (in an exemplary mode by a factor ∼30), while simultaneously increasing coupling efficiencies. We propose illustrative schemes to engineer the necessary elliptical transitions in both atomic systems and quantum dots.

Collectively Enhanced Chiral Photon Emission from an Atomic Array near a Nanofiber.

Emitter ensembles interact collectively with the radiation field. In the case of a one-dimensional array of atoms near a nanofiber, this collective light-matter interaction does not only lead to an increased photon coupling to the guided modes within the fiber, but also to a drastic enhancement of the chirality in the photon emission. We show that near-perfect chirality can be achieved already for moderately sized ensembles, containing 10 to 15 atoms, by phase matching a superradiant collective guided emission mode via an external laser field. This is of importance for developing an efficient interface between atoms and waveguide structures with unidirectional coupling, with applications in quantum computing and communication such as the development of nonreciprocal photon devices or quantum information transfer channels.

Perinatal outcomes in nulliparous women with a history of multiple pregnancy losses according to number of previous pregnancy losses.

BACKGROUND: While it is widely acknowledged that pregnancy losses can lead to negative outcomes for both mothers and fetuses, there is limited information available on the specific levels of risk associated with each additional pregnancy loss. OBJECTIVE: This study aimed to investigate the effect of number of previous pregnancy losses among nulliparous women on maternal and neonatal adverse outcomes. STUDY DESIGN: This was a multicenter retrospective cohort study. The study population included all nulliparous women with singleton pregnancies who delivered in all university-affiliated obstetrical centers in a single geographic area between 2003 and 2021. Maternal and neonatal outcomes of women who delivered at our medical centers and had varying numbers of previous pregnancy losses were compared with women who had no previous pregnancy loss. The primary outcome of this study was preterm delivery rate at <37 weeks of gestation. The secondary outcomes were adverse maternal and neonatal outcomes. Univariate analysis was performed using multiple logistic regression modeling. RESULTS: During the study period, 97,904 nulliparous women met the inclusion and exclusion criteria. Of those women, 84,245 (86%) had no previous pregnancy losses (reference group), 10,724 (11%) had 1 previous pregnancy loss, 2150 (2.2%) had 2 previous pregnancy losses, 516 (0.5%) had 3 previous pregnancy losses, 160 (0.2%) had 4 previous pregnancy losses, and 99 (0.1%) had ≥5 previous pregnancy losses. Women who had previous pregnancy losses had significantly higher rates of preterm delivery, hypertensive disorders of pregnancy, diabetes mellitus (pregestational and gestational), unplanned cesarean delivery, perinatal death, neonatal intensive care unit admissions, and neonatal hypoglycemia. The risks of preterm delivery and most other adverse obstetrical outcomes correlated with the number of previous pregnancy losses. Multivariate analyses showed that each previous pregnancy loss was associated with an additional, significant, increased risk of preterm delivery of 14% at <37 weeks of gestation, 37% at <34 weeks of gestation, 45% at <32 weeks of gestation, and 77% at <28 weeks of gestation. CONCLUSION: A history of previous pregnancy losses increased the risk of preterm delivery and other perinatal outcomes in a dose-dependent manner. To minimize perinatal complications, obstetricians should be aware of the risks and complications in this unique population, consider close monitoring of the cervical length, and maintain high vigilance in case of complications with special attention to other potentially modifiable risks.

Epidural analgesia and vacuum-assisted delivery in primiparous women: maternal and neonatal outcomes.

OBJECTIVE: We aimed to evaluate the effect of epidural analgesia (EA) on maternal and neonatal outcomes. METHODS: We conducted a retrospective cohort database study on primiparous women who underwent a vacuum-assisted delivery (VAD) trial between 2005 and 2019 at a university-affiliated tertiary medical center. We compared women with and without the standard "one protocol" patient-controlled EA. The primary outcome was VAD failure. Secondary outcomes were maternal and neonatal morbidities. We performed univariate analysis, followed by multivariable logistic regression analysis to control for potential confounders. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. RESULTS: Overall, 7042 primiparous women attempted VAD during the study period; 6238 (88.3%) and 804 (11.7%) women used and did not use EA, respectively. The VAD failure rate was significantly lower among women with than without EA use (2.5% vs. 4.2%, respectively, p < .01). On multivariable analysis, EA use was found to reduce the VAD failure rate (aOR, 0.05; 95% CI [0.01-0.49], p = .01). Notably, EA use was not associated with an increased rate of any maternal or neonatal adverse outcome (aOR, 1.01; 95% CI [0.8-1.27], p = .95 or aOR, 1.14 95% CI [0.89-1.45], p = .3, respectively). CONCLUSIONS: EA use in primiparous women is associated with lower rates of VAD failure without an increase in adverse maternal or neonatal outcomes.

Twin pregnancy following a short interpregnancy interval: Maternal and neonatal outcomes.

OBJECTIVE: To evaluate maternal and neonatal outcomes of women with twin pregnancies following a short interpregnancy interval (IPI < 6 months). STUDY DESIGN: A retrospective computerized database study in a single tertiary medical center between 2005 and 2021. Women who had an index singleton delivery and a subsequent twin gestation in their next pregnancy at the Shaare Zedek Medical Center (SZMC) were included. Maternal and neonatal outcomes of twin pregnancies following a short IPI (<6 months) were compared to those with an optimal IPI (18-48 months). Univariate analysis was followed by multiple logistic regression models; adjusted odds ratios (aORs) and 95 % confidence intervals (CIs) were calculated. RESULTS: During the study period, 2,079 women had an index singleton delivery followed by a twin gestation in their next pregnancy recorded at our medical center; 116 (5.9 %) had a history of short IPI, and 1,057 (50.8 %) had a history of optimal IPI. Women with a history of short IPI had higher rates of preterm labor < 37 weeks and < 34 weeks, NICU admissions and prolonged hospital stay of the first and second fetuses, mechanical ventilation of the first fetus, 1 and 5 Minute Apgar score lower than 7 of the second fetus and lower rates of elective cesarean delivery. An adjusted multivariate analysis showed that a history of short IPI was not an independent risk factor for preterm birth either < 34 weeks or < 37 weeks or for composite adverse neonatal outcome of the first and second twin. CONCLUSION: Twin pregnancy following a short IPI was not associated with neither preterm labor nor composite adverse neonatal outcome.

Maternal and Neonatal Outcomes of Women Conceived Less Than 6 Months after First Trimester Dilation and Curettage.

Objective: To evaluate the maternal and neonatal outcomes of pregnancies conceived ≤6 months after first trimester (<14 weeks) dilation and curettage (D&C). Methods: A retrospective computerized database study of women who conceived ≤6 months following a missed abortion and delivered in a single tertiary medical center between 2016 and 2021. The maternal and neonatal outcomes of women who had D&C were compared to those of women who had non-medical or spontaneous miscarriages. The primary outcome of this study was the rate of preterm birth (<37 weeks). Secondary outcomes were adverse maternal and neonatal outcomes. Univariate analysis was followed by multiple logistic regression models; adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. Results: During the study period, 1773 women met the inclusion criteria; of those, 1087 (61.3%) women gave birth following D&C. We found no differences between the study groups in any maternal or neonatal parameter examined including preterm birth (PTB), miscarriage to pregnancy interval, fertility treatments, hypertension disorders of pregnancy, placental complications, mode of delivery and neonatal birth weights. This was confirmed on a multivariate analysis as well [aOR 1.74 (0.89−3.40), p = 0.11] for preterm birth. Conclusion: Watchful waiting or the medical treatment of a first trimester missed abortion present no more risks than D&C to pregnancies conceived within six months of the index miscarriage. Further studies in other settings to strengthen these findings are needed.

Role of Heat Shock Factors in Stress-Induced Transcription.

Heat shock proteins (HSP) are rapidly induced after stresses such as heat shock and accumulate at high concentrations in cells. HSP induction involves primarily a family of heat shock transcription factors (HSF) that bind the heat shock elements of the HSP genes and mediate transcription in trans. We discuss methods for the study of HSP binding to HSP promoters and the consequent increases in HSP gene expression in vitro and in vivo.

Time-reversal constraint limits unidirectional photon emission in slow-light photonic crystals.

Photonic crystal waveguides are known to support C-points-point-like polarization singularities with local chirality. Such points can couple with dipole-like emitters to produce highly directional emission, from which spin-photon entanglers can be built. Much is made of the promise of using slow-light modes to enhance this light-matter coupling. Here we explore the transition from travelling to standing waves for two different photonic crystal waveguide designs. We find that time-reversal symmetry and the reciprocal nature of light places constraints on using C-points in the slow-light regime. We observe two distinctly different mechanisms through which this condition is satisfied in the two waveguides. In the waveguide designs, we consider a modest group velocity of vg≈c/10 is found to be the optimum for slow-light coupling to the C-points.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'.

The Helicobacter pylori cytotoxin CagA is essential for suppressing host heat shock protein expression.

Bacterial infections typically elicit a strong Heat Shock Response (HSR) in host cells. However, the gastric pathogen Helicobacter pylori has the unique ability to repress this response, the mechanism of which has yet to be elucidated. This study sought to characterize the underlying mechanisms by which H. pylori down-modulates host HSP expression upon infection. Examination of isogenic mutant strains of H. pylori defective in components of the type IV secretion system (T4SS), identified the secretion substrate, CagA, to be essential for down-modulation of the HSPs HSPH1 (HSP105), HSPA1A (HSP72), and HSPD1 (HSP60) upon infection of the AGS gastric adenocarcinoma cell line. Ectopic expression of CagA by transient transfection was insufficient to repress HSP expression in AGS or HEK293T cells, suggesting that additional H. pylori factors are required for HSP repression. RT-qPCR analysis of HSP gene expression in AGS cells infected with wild-type H. pylori or isogenic cagA-deletion mutant found no significant change to account for reduced HSP levels. In summary, this study identified CagA to be an essential bacterial factor for H. pylori-mediated suppression of host HSP expression. The novel finding that HSPH1 is down-modulated by H. pylori further highlights the unique ability of H. pylori to repress the HSR within host cells. Elucidation of the mechanism by which H. pylori achieves HSP repression may prove to be beneficial in the identification of novel mechanisms to inhibit the HSR pathway and provide further insight into the interactions between H. pylori and the host gastric epithelium.