Normal amniotic pressure throughout gestation

Fisk, Nicholas M.; Ronderos-Dumit, Daniel; Tannirandorn, Yuen; Nicolini, Umberto; Talbert, D.G.; Rodeck, Charles H.

doi:10.1111/j.1471-0528.1992.tb14385.x

Cited by 59 publications

(50 citation statements)

References 18 publications

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“…AP results were expressed as z scores (standard deviations) of our reference mean [21]. Blood gas results were compared to published ref erence ranges [22].…”

Section: Methodsmentioning

confidence: 99%

Impaired Fetal Blood Gas Status in Polyhydramnios and Its Relation to Raised Amniotic Pressure

Fisk

Vaughan

Talbert³

1994

Fetal Diagn Ther

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A substantial proportion of perinatal losses in polyhydramnios occur as unexplained normally formed stillbirths. In order to investigate the relationship between fetal condition and raised amniotic pressure (AP), fetal blood gas and acid-base status were determined together with AP in 22 pregnancies with polyhydramnios. At fetal blood sampling, 8 (36%) had a venous pH value and 16 (73%) a pO₂ value below the reference range. Both fetal pH and pO₂ were significantly negatively correlated with the degree of elevation in AP (y = 7.43 ––0.036x, r = 0.56, p = 0.006, where y = pH and x = AP z score, and y = ––1.6 – 0.48x, r = 0.54, p = 0.01, where y = pO₂ z score, respectively). Although some of these fetuses were hydropic, had congenital anomalies, or were from multiple pregnancies, univariate and multiple logistic regression analyses indicated that the above associations could not be accounted for by these potentially confounding variables. This work suggsts that abnormal fetal blood gas status in human pregnancies with polyhydramnios is associated with elevated AP.

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“…AP results were expressed as z scores (standard deviations) of our reference mean [21]. Blood gas results were compared to published ref erence ranges [22].…”

Section: Methodsmentioning

confidence: 99%

Impaired Fetal Blood Gas Status in Polyhydramnios and Its Relation to Raised Amniotic Pressure

Fisk

Vaughan

Talbert³

1994

Fetal Diagn Ther

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“…The foetus grows in an almost (but not quite) weightless environment, with the decreasing ratio of amniotic to foetal volume likely leading to an decreased buoyancy as term approaches (Makepeace et al, 1931;Wood, 1970). Amniotic fluid pressure increases over gestation (Fisk et al, 1992), and is abnormal in severe cases of abnormal amniotic fluid volume (oligohydramnios or polyhydramnios) (Fisk et al, 1990). However, it is not known if fluid pressure has any direct effects on foetal movements.…”

Section: Properties Of the Foetal Environmentmentioning

confidence: 99%

Biomechanics of foetal movement

Nowlan¹

2015

eCM

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Foetal movements commence at seven weeks of gestation, with the foetal movement repertoire including twitches, whole body movements, stretches, isolated limb movements, breathing movements, head and neck movements, jaw movements (including yawning, sucking and swallowing) and hiccups by ten weeks of gestational age. There are two key biomechanical aspects to gross foetal movements; the first being that the foetus moves in a dynamically changing constrained physical environment in which the freedom to move becomes increasingly restricted with increasing foetal size and decreasing amniotic fluid. Therefore, the mechanical environment experienced by the foetus affects its ability to move freely. Secondly, the mechanical forces induced by foetal movements are crucial for normal skeletal development, as evidenced by a number of conditions and syndromes for which reduced or abnormal foetal movements are implicated, such as developmental dysplasia of the hip, arthrogryposis and foetal akinesia deformation sequence. This review examines both the biomechanical effects of the physical environment on foetal movements through discussion of intrauterine factors, such as space, foetal positioning and volume of amniotic fluid, and the biomechanical role of gross foetal movements in human skeletal development through investigation of the effects of abnormal movement on the bones and joints. This review also highlights computational simulations of foetal movements that attempt to determine the mechanical forces acting on the foetus as it moves. Finally, avenues for future research into foetal movement biomechanics are highlighted, which have potential impact for a diverse range of fields including foetal medicine, musculoskeletal disorders and tissue engineering.Keywords: Foetal movement, fetal movement, bone development, joint development, developmental dysplasia of the hip, arthrogryposis, biomechanical models, computational simulation, mechanical properties of foetal tissues, mechanical properties of fetal tissues.

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“…accentuated in twin pregnancies despite normal amniotic pressure (10,32) because of the relationship between amniotic pressure, uterine radius, and myometrial tension. Interestingly, the risk of preterm labor is particularly high in pregnancies associated with increased intrauterine volume including multifetal pregnancies (11), polyhydramnios (14), and singleton pregnancies with a larger than average fetus (25).…”

mentioning

confidence: 99%

Mitogen-activated protein kinases mediate stretch-induced c-fos mRNA expression in myometrial smooth muscle cells

Oldenhof

Shynlova

Liu

et al. 2002

American Journal of Physiology-Cell Physiology

123

102

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. Mitogen-activated protein kinases mediate stretch-induced c-fos mRNA expression in myometrial smooth muscle cells. Am J Physiol Cell Physiol 283: C1530-C1539, 2002. First published July 3, 2002 10.1152 10. /ajpcell.00607.2001 indicates that stretch of the uterus imposed by the growing fetus contributes to the onset of labor. Previously we have shown that mechanically stretching rat myometrial smooth muscle cells (SMCs) induces c-fos expression. To investigate this stretch-induced signaling, we examined the involvement of the mitogen-activated protein kinase (MAPK) family. We show that stretching rat myometrial SMCs induces a rapid and transient phosphorylation (activation) of MAPKs: extracellular signal-regulated protein kinase (ERK), c-Jun NH 2-terminal kinase (JNK), and p38. The use of selective inhibitors for the ERK pathway (PD-98059 and U-0126), p38 (SB-203580), and JNK pathway (curcumin) demonstrated that activation of all three MAPK signaling pathways was necessary for optimal stretch-induced c-fos expression. We also demonstrate that upstream tyrosine kinase activity is involved in the mechanotransduction pathway leading to stretch-induced MAPK activation and c-fos mRNA expression. To further examine the role of MAPKs in vivo, we used a unilaterally pregnant rat model. MAPKs (ERK and p38) are expressed in the pregnant rat myometrium with maximal ERK and p38 phosphorylation occurring in the 24 h immediately preceding labor. Importantly, the rise in MAPK phosphorylation was confined to the gravid horn and was absent in the empty uterine horn, suggesting that mechanical strain imposed by the growing fetus controls MAPK activation in the myometrium. Collectively, this data indicate that mechanical stretch modulates MAPK activity in the myometrium leading to c-fos expression.

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Normal amniotic pressure throughout gestation

Cited by 59 publications

References 18 publications

Impaired Fetal Blood Gas Status in Polyhydramnios and Its Relation to Raised Amniotic Pressure

Impaired Fetal Blood Gas Status in Polyhydramnios and Its Relation to Raised Amniotic Pressure

Biomechanics of foetal movement

Mitogen-activated protein kinases mediate stretch-induced c-fos mRNA expression in myometrial smooth muscle cells

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