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- Moen, Vibeke, et al.
(author)
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Feto-maternal osmotic balance at term. A prospective observational study
- 2018
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In: Journal of Perinatal Medicine. - : WALTER DE GRUYTER GMBH. - 0300-5577 .- 1619-3997. ; 46:2, s. 183-189
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Journal article (peer-reviewed)abstract
- Objective: We performed the present study to investigate the feto-maternal osmotic relationship at term with the hypothesis that, in contrast to the literature, maternal plasma osmolality is lower than fetal levels. In a previous study, we found that maternal plasma sodium at delivery was consistently lower than the sodium in the umbilical artery. Our aim was to corroborate these results with analysis of osmolality. Methods: Blood was sampled from 30 women immediately before cesarean section and from the umbilical artery and vein before cord clamping and osmolality, sodium and albumin were analyzed. Results: Maternal osmolality was (mean; 95% confidence interval) 287.0 (285.8-288.2) mOsmkg/kg, arterial cord osmolality was 289.4 (287.9-291.0) mOsm/kg and venous cord osmolality was 287.3 (286.0-288.5) mOsm/kg. The paired difference between maternal and umbilical arterial osmolality was mean (SD) -2.4 (3.3) mOsm/kg (P amp;lt; 0.001), between maternal and umbilical vein -0.3 (3.0) mOsm/kg (P = 0.63) and between umbilical artery and vein -2.1 (2.8) mOsm/kg (P amp;lt; 0.001). Conclusion: Maternal osmolality was significantly lower than arterial cord osmolality confirming our previous results. The feto-maternal osmotic gradient favors water transport from the mother to the fetus and may increase the fetal risk of water intoxication when the mother ingests or is administered large volumes of electrolyte free solutions.
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| 2. |
- Moen, Vibeke, et al.
(author)
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Hyponatraemia reversibly affects human myometrial contractility. An in vitro pilot study
- 2020
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In: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 15:1
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Journal article (peer-reviewed)abstract
- Background In a previous study we found a significant correlation between dystocia and hyponatraemia that developed during labour. The present study examined a possible causal relationship. In vitro studies often use area under the curve (AUC) determined by frequency and force of contractions as a measure of myometrial contractility. However, a phase portrait plot of isometric contraction, obtained by plotting the first derivate of contraction against force of contraction, could indicate that bi-or multiphasic contractions might be less effective compared to the smooth contractions. Material and methods Myometrial biopsies were obtained from 17 women undergoing elective caesarean section at term. Each biopsy was divided into 8 strips and mounted isometrically in a force transducer. Seven biopsies were used in the first part of the study when half of the strips were immersed in the hyponatraemic study solution S containing Na+ 120 mmol/L and observed for 1 hour, followed by 1 hour in normonatraemic control solution C containing Na+ 136 mmol/L, then again in S for 1 hour, and finally 1 hour in C. The other half of the strips were studied in reverse order, C-S-C-S. The remaining ten biopsies were included in the second part of the study. Response to increasing doses of oxytocin (OT) in solutions S and C was studied. In the first part of the study we calculated AUC, and created phase portrait plots of two different contractions from the same strip, one smooth and one biphasic. In both parts of the study we registered frequency and force of contractions, and described appearance of the contractions. Results First part of the study: Mean (median) contractions per hour in C: 8.7 (7.6), in S 14,3 (13). Mean (SD) difference between groups 5.6 (4.2), p = 0.018. Force of contractions in C: 11.8 (10.2) mN, in S: 10.8 (9.2) mN, p = 0.09, AUC increased in S; p = 0.018. Bi-/multiphasic contractions increased from 8% in C to 18% in S, p = 0.001. All changes were reversible in C. Second part of the study: Frequency after OT 1.65 x 10-(9) M in C:3.4 (2.9), in S: 3.8 (3.2), difference between groups: p = 0.48. After OT 1.65 x 10-(7) M in C: 7.8 (8.9), increase from previous OT administration: p = 0.09, in S: 8.7 (9.0), p = 0.04, difference between groups, p = 0.32. Only at the highest dose of OT dose was there an increase in force of contraction in S, p = 0.05, difference between groups, p = 0.33. Initial response to OT was more frequently bi/multiphasic in S, reaching significance at the highest dose of OT(1.65 x 10-(7) M), p = 0.015. when almost all contractions were bi/multiphasic. Conclusion Hyponatraemia reversibly increased frequency of contractions and appearance of bi-or multiphasic contractions, that could reduce myometrial contractility. This could explain the correlation of hyponatraemia and instrumental delivery previously observed. Contractions in the hyponatraemic solution more frequently showed initial multiphasic contractions when OT was added in increasing doses. Longer lasting labours carry the risk both of hyponatraemia and OT administration, and their negative interaction could be significant. Further studies should address this possibility.
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| 5. |
- Darvish, Bijan, 1969-
(author)
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Post-Dural Puncture Headache in Obstetrics : Audiological, Clinical and Epidemiological studies
- 2016
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Doctoral thesis (other academic/artistic)abstract
- Post-dural puncture headache (PDPH) is the most common complication of obstetric epidural analgesia. The characteristic positional headache, often associated with visual, vestibular or cochlear symptoms, is severe and disabling for the parturient. The diagnosis is clinical without the possibility of confirmatory objective tests. Although epidural blood patch (EBP) is considered the gold standard for treatment of PDPH, many aspects of this treatment modality remain to be explored. This thesis was performed in order to improve our current knowledge of the diagnosis and the short and long-term consequences of PDPH. We found that the incidence of accidental dural puncture in labour epidural analgesia was 1% in the Nordic countries and 90% of these patients were managed with an EBP (study I). Auditory impairment related to PDPH was prospectively investigated in 21 parturients with PDPH treated with EBP (study II). A significantly greater number of parturients suffering from PDPH had hearing loss (> 20 dB) in the low frequency range compared to controls which improved spontaneously but independent of treatment with EBP. At 4 hours, 95% of subjects had a successful EBP but headache recurred in 24% at 24 hours. In study III, we investigated residual hearing deficit several years after PDPH treated with EBP. We found statistically significant long-term impairment of hearing but this was of minor clinical relevance. In study IV, 60 women with previous PDPH and treated with EBP responded to a validated questionnaire to determine the long-term effects of EBP on headache and backache. We found that subjects who had been treated with EBP had a significantly greater incidence and severity of headache compared to controls. The incidence of mild backache was also significantly higher but of limited clinical importance. In conclusion, PDPH after labour epidural analgesia is an important clinical problem. Parturients suffering from PDPH may have audiometric deterioration in the early postpartum period that recovers spontaneously over time and some long-term effects of PDPH on hearing may be evident but these are of minor clinical relevance. Clinically important headache, but not backache, may be present several years after PDPH.
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| 6. |
- Ericson, Per G P, 1956-, et al.
(author)
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A 14,000-year-old genome sheds light on the evolution and extinction of a Pleistocene vulture
- 2022
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 5:1
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Journal article (peer-reviewed)abstract
- The New World Vulture [Coragyps] occidentalis (L. Miller, 1909) is one of many species that were extinct by the end of the Pleistocene. To understand its evolutionary history we sequenced the genome of a 14,000 year old [Coragyps] occidentalis found associated with megaherbivores in the Peruvian Andes. occidentalis has been viewed as the ancestor, or possibly sister, to the extant Black Vulture Coragyps atratus, but genomic data shows occidentalis to be deeply nested within the South American clade of atratus. Coragyps atratus inhabits lowlands, but the fossil record indicates that occidentalis mostly occupied high elevations. Our results suggest that occidentalis evolved from a population of atratus in southwestern South America that colonized the High Andes 300 to 400 kya. The morphological and morphometric differences between occidentalis and atratus may thus be explained by ecological diversification following from the natural selection imposed by this new and extreme, high elevation environment. The sudden evolution of a population with significantly larger body size and different anatomical proportions than atratus thus constitutes an example of punctuated evolution.
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| 7. |
- Fjeldså, Jon, et al.
(author)
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Description of two new Cisticola species endemic to the marshes of the Kilombero floodplain of southwestern Tanzania
- 2021
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In: Ibis. - : Wiley. - 0019-1019 .- 1474-919X. ; 163:4, s. 1330-1354
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Journal article (peer-reviewed)abstract
- The presence of two undescribed cisticola warblers in the marshes of the Kilombero floodplain in central Tanzania has been known since the 1980s and these putative new species have been illustrated in field guides on African birds, although with no formal name. Here we name both species, based on two museum specimens collected in 1961 and recently detected in a museum collection. We use these specimens to provide formal descriptions of each form and, using DNA sequence data extracted from these specimens, we place them in a broad phylogenetic framework for the genus Cisticola. The phylogenetic placement indicates that one of the new species is nested within a group of plain-backed duetting cisticolas and the other within the streak-backed marsh cisticolas. We use our own and public recordings to characterize the vocal repertoire of each of these new species and compare song characteristics with other members of their respective clades. Dating of nodes in the molecular phylogeny suggests that both cisticolas endemic to the Kilombero became isolated and diverged from their sister-species between 2.5 and 3.5 million years ago, long after the formation of the Eastern Arc Mountains and the Malawi Rift. We propose that both species should be classified as globally endangered, owing to immense anthropogenic pressures on the floodplain, as documented in several publications and by a recent Ramsar Advisory Mission.
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| 9. |
- Moen, V, et al.
(author)
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Hyponatremia complicating labour-rare or unrecognised? A prospective observational study
- 2009
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In: BJOG-AN INTERNATIONAL JOURNAL OF OBSTETRICS AND GYNAECOLOGY. - : Wiley. - 1470-0328 .- 1471-0528. ; 116:4, s. 552-561
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Journal article (peer-reviewed)abstract
- The aim of this study was to investigate the occurrence of hyponatraemia following delivery, with a hypothesis that hyponatraemia has a high prevalence in labouring women. Prospective observational study. Consultant-led delivery suite in County Hospital, Kalmar, Sweden. A total of 287 pregnant women at term (37 full gestational weeks). Oral fluids were allowed during labour. Blood samples were collected on admission, after delivery, and from the umbilical artery and vein. Hyponatraemia defined as plasma sodium <= 130 mmol/l after delivery. Hyponatraemia was found in 16 (26%) of the 61 mothers who received more than 2500 ml of fluid during labour. Two-thirds of fluids were orally ingested. Decrease in plasma sodium concentration during labour correlated with duration of labour and the total fluid volume administered. Analysis by multivariate logistic regression showed that hyponatraemia was significantly correlated with fluid volume (P < 0.001) but not with oxytocin administration or epidural analgesia. Hyponatraemia correlated significantly with prolonged second stage of labour, instrumental delivery, and emergency caesarean section for failure to progress (P = 0.002). Hyponatraemia is not uncommon following labour. Tolerance to a water load is diminished during labour; therefore, even moderate fluid volumes may cause hyponatraemia. Women should not be encouraged to drink excessively during labour. Oral fluids, when permitted, should be recorded, and intravenous administration of hypotonic fluids should be avoided. When abundant drinking is unrecognised or intravenous fluid administration liberal, life-threatening hyponatraemia may develop. The possibility that hyponatraemia may influence uterine contractility merits further investigation.
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