Browsing by Author "Palma dos Reis, C"
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- Alvarez Waves in Pregnancy: a Comprehensive ReviewPublication . Russo, S; Batista, A; Esgalhado, F; Palma dos Reis, C; Serrano, F; Vassilenko, V; Ortigueira, MAlvarez waves are local rhythmic contractions of the myometrium with high frequency and low intensity. They can be detected using internal or external tocography and electrohysterography. Some researchers correlate these small contractions with the initiation of labor, since they have been described as a pattern representing the uterine response to prostaglandin production. Other authors either do not validate a causality relation between Alvarez waves and labor or suggest that they have low predictive value for preterm labor. Alvarez waves' research has become a multidisciplinary subject with inputs ranging from medical science, biomedical engineering, and related areas. A comprehensive review is herein conducted to summarize the state of the art regarding Alvarez waves and their role in the initiation of labor, namely in preterm birth. The results show that a large number of studies have analyzed and characterized Alvarez waves without necessarily digging into their relationship with labor. Publications were categorized in three groups: (A) reports about morphology and characterization of Alvarez waves; (B) publications reporting a positive causality relation between Alvarez waves and labor; and (C) publications reporting an absence of causality regarding the previous hypothesis. Studies in group B outnumbered those in group C. A critical analysis is presented.
- Prediction of Adverse Pregnancy Outcomes in Women with Systemic Lupus ErythematosusPublication . Palma dos Reis, C; Cardoso, G; Carvalho, C; Nogueira, I; Borges, A; Serrano, FSystemic lupus erythematosus (SLE) is a chronic, autoimmune disease associated with major obstetrical complications such as gestational loss, preterm delivery, fetal growth restriction (FGR) and preeclampsia. Published literature is not consensual regarding the main risk factors for each of these outcomes. Our goal with this study was to determine the most important predictors for each of the main adverse pregnancy outcomes in this population. We conducted a retrospective cohort study of unifetal pregnancies of women with the diagnosis of SLE followed in our unit between January 1994 and December 2016. We excluded elective terminations of pregnancy and cases lost to follow-up and we analyzed 157 pregnancies (128 women). Multiple logistic regression models for the outcomes gestational loss, preterm delivery, fetal growth restriction, and preeclampsia were built. Two-sided p-values of < 0.05 were used to determine statistical significance, and two-sided confidence intervals of 95% are reported. In our cohort, the main risk factors for gestational loss were maternal age and the presence of antiphospholipid antibodies. Lupic nephritis was predictive of a preterm delivery and preeclampsia. Renal involvement and lupus flares during pregnancy were risk factors for FGR. Overall, the main risk factor for an adverse pregnancy outcome were lupus flares during pregnancy. Despite optimal pregnancy monitoring, women with SLE are still at risk for adverse pregnancy outcomes. Risk stratification for each of these outcomes is crucial for an effective counselling and tailored monitoring.
- A Preliminary Exploration of the Placental Position Influence on Uterine Electromyography Using Fractional ModellingPublication . Şan, M; Batista, A; Russo, S; Esgalhado, F; Palma dos Reis, C; Serrano, F; Ortigueira, MThe uterine electromyogram, also called electrohysterogram (EHG), is the electrical signal generated by uterine contractile activity. The EHG has been considered an expanding technique for pregnancy monitoring and preterm risk evaluation. Data were collected on the abdominal surface. It has been speculated the effect of the placenta location on the characteristics of the EHG. In this work, a preliminary exploration method is proposed using the average spectra of Alvarez waves contractions of subjects with anterior and non-anterior placental position as a basis for the triple-dispersion Cole model that provides a best fit for these two cases. This leads to the uterine impedance estimation for these two study cases. Non-linear least square fitting (NLSF) was applied for this modelling process, which produces electric circuit fractional models' representations. A triple-dispersion Cole-impedance model was used to obtain the uterine impedance curve in a frequency band between 0.1 and 1 Hz. A proposal for the interpretation relating the model parameters and the placental influence on the myometrial contractile action is provided. This is the first report regarding in silico estimation of the uterine impedance for cases involving anterior or non-anterior placental positions.