Analysis of hemi-uterus pregnancy outcomes in uterine malformations: a retrospective observational study.

BACKGROUND: The association between uterine malformations and adverse pregnancy outcomes is well recognized. However, studies on adverse pregnancy outcomes based on one kind of anatomical commonality between different uterine anomalies have not been reported. This study aimed to investigate pregnancy outcomes in pregnancies with uterine malformations when the pregnancy is confined to a hemi-uterus. METHODS: A retrospective observational study of 336 women who gave birth at our hospital from 2015 to 2021 was performed. Women (n = 112) with a unicornuate, complete bicornuate, or didelphic uterus were set as the study group, and women (n = 224) with a normal uterus were set as the reference group. Maternal and neonatal outcomes were evaluated and compared between the two groups using Student's t-test, one-way ANOVA, Chi-squared test, Yates correction for continuity, or Fisher's exact test. Modified Poisson regression analyses were used to estimate the relationships between the hemi-uterus pregnancy and preterm birth, preterm premature rupture of membranes, and cesarean section rates by adjusting for potential confounders. A P value < 0.05 was considered significant. RESULTS: Women in the study group had a higher history of spontaneous abortion (24.1% vs. 10.7%, P = 0.002) and intrauterine fetal death (5.4% vs. 0.4, P = 0.006). Compared with the reference group, the study group had significantly higher rates of assisted reproductive technology (9.4% vs. 2.2%, P = 0.001) and cord-around-the neck (54.5% vs. 29.9%, P = 0.000). Modified Poisson regression analyses showed that the study group was at higher risk for preterm birth (aRR, 6.8; 95% CI 2.7-16.7), preterm premature rupture of membranes (aRR, 14.1; 95% CI 3.2-62.5), malpresentation (aRR, 13.2; 95% CI 6.3-27.7), and cesarean section (aRR, 4.4; 95% CI 3.3-5.7). CONCLUSION: Women with a unicornuate, didelphic, or complete bicornuate uterus are at higher risk for some adverse pregnancy outcomes than those with a normal uterus.

Efficient and accurate phase-measurement method for core-loss characterization.

Accurate core-loss characterization is essential to push the power density of power converters to their limits. However, existing core-loss measurement methods still have some limitations, such as a slow test speed and a complex probe calibration procedure. In particular, accurate phase-difference measurement is time-consuming because a fast Fourier transform analysis with a kHz-range frequency interval is typically applied to reduce the influence of noise. An automated measurement system for magnetic core-loss characterization is described in this paper. An accurate phase-detection block with programmable attenuators is developed to measure the phase difference between voltage and current waveforms. The proposed system considerably improves the test speed while providing comparable accuracy to the existing method.

Modular high-voltage bias generator powered by dual-looped self-adaptive wireless power transmission.

We proposed a modular high-voltage (HV) bias generator powered by a novel transmitter-sharing inductive coupled wireless power transmission technology, aimed to extend the generator's flexibility and configurability. To solve the problems caused through an uncertain number of modules, a dual-looped self-adaptive control method is proposed that is capable of tracking resonance frequency while maintaining a relatively stable induction voltage for each HV module. The method combines a phase-locked loop and a current feedback loop, which ensures an accurate resonance state and a relatively constant boost ratio for each module, simplifying the architecture of the boost stage and improving the total efficiency. The prototype was built and tested. The input voltage drop of each module is less than 14% if the module number varies from 3 to 10; resonance tracking is completed within 60 ms. The efficiency of the coupling structure reaches up to 95%, whereas the total efficiency approaches 73% for a rated output. Furthermore, this technology can be used in various multi-load wireless power supply applications.