Influence of uterine contractions on the uteroplacental blood flow at term

Borell, Ulf; Fernström, Ingmar; Ohlson, Lars; Wiqvist, N.

doi:10.1016/0002-9378(65)90293-0

Cited by 112 publications

(34 citation statements)

References 7 publications

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“…Direct investigations in the human using intravascular radio-opaque dye have also demonstrated that during uterine contractions there could be afferent arterial constriction and occlusion within the uterine musculature, together with reduced placental intervillous filling ( 16). Investigations in the human, using Doppler, have confirmed the inverse correlation between uterine muscular activity and associated increased intrauterine pressure on the one hand, and decreased afferent uterine flow on the other.…”

Section: I42mentioning

confidence: 85%

Asphyxia, Cerebral Palsy and Litigation

Beavis¹

1999

Aust NZ J Obst Gynaeco

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EDITORIAL COMMENT: This contribirtion w~i s suhnzitterl ,for consider(ition .fi)r publicution as u letter to the editor: The uuthor is one of' Austruliu's most senior obstetricians. The editor Ims known him well ,for 45 years und c.otz.sirler.s him to he both un impressive scholcir uncIjofi,rmidrd.de iconoclast. I n ciu'dition he is writing on his ,favourite subject, concerning which he has anulyzecl the releiwit liternture ,for muny years, often in relation to providing opinions in C N S~S being consiclerecljbr litiption. He also has the distinction of usiiullv prmriu'ing opinions ,from the point of viecc. of patients ruther than dcfenu'unts (ohstetricinns, hospitals) in such cuses. We have not invited the authors whose pupers are nzentioned to respond to his comments. The editorial committee of the journal und oiir other reviewers ugreed that this muterial should he ofered to our readers us it stutids f i i r their considerution.

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Section: I42mentioning

confidence: 85%

Asphyxia, Cerebral Palsy and Litigation

Beavis¹

1999

Aust NZ J Obst Gynaeco

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“…Borell et al (1965), in a study of pregnant women at or near term, found varyextension (BME) that sandwiches the mesometrial vessels and ends as a free edge midway across the mesometrium. The mesometrial veins drain to the uterine vein (Uv).…”

Section: Discussionmentioning

confidence: 98%

Mesometrial smooth muscle in the mouse: Its control of uterine blood flows

Liebgott

1984

Anat. Rec.

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The form and function of the mesometrial smooth muscle and the interposed mesometrial branches and tributaries of the uterine vessels were studied in the nonpregnant and pregnant mouse to see whether contractions of mesometrial muscle alter uterine blood flows. Histological sections of mouse uterine horn demonstrated that the outer longitudinal layer of myometrium extends onto the mesometrium and sandwiches the mesometrium and its vessels as a bilaminar myometrial extension (BME). The BME ends midway across the mesometrium as a free edge. Cleared specimens, perfused with silicone rubber, revealed that the mesometrial branches and tributaries of the uterine vessels formed longitudinally communicating looping arcades between adjacent mesometrial vessels. Comparisons with human dissections and uterine histological sections revealed similar patterns of mesometrial smooth muscle and mesometrial blood vessels. BME activity and its control of mesometrial blood flow were studied by transillumination of the surgically exposed mesometria of anesthetized day 12 pregnant mice. Observed contractions of the BME coincided precisely with uterine contractions measured at the cervix and the BME contractions diminished or stopped venous outflow particularly in the midhorn regions. Arterial flows seemed to be unaffected and were diminished or halted only during infrequent forceful and sustained contractions. Trapped venous outflow passed up or down the venous arcades to escape through less restricted mesometrial veins. Uterine and BME contractions normally take place throughout gestation. It is possible that abnormally long and forceful contractions may compromise the embryo or fetus.

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“…Furthermore Doppler ultrasound studies have demonstrated an inverse relationship between uterine artery resistance and the intensity of uterine contractions during labour [14]. It has been shown in chronically instrumented pregnant rhesus monkeys that placental blood flow is almost completely stopped during sustained myometrial contractions and that this occurs as a result of compression of the arcuate and spiral arteries [15], [16]. The closest human model to this was performed on patients prior to termination of pregnancy at 17–20 weeks of gestation [17].…”

Section: Discussionmentioning

confidence: 99%

Paraoxonase 2 Protein Is Spatially Expressed in the Human Placenta and Selectively Reduced in Labour

et al. 2014

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Humans parturition involves interaction of hormonal, neurological, mechanical stretch and inflammatory pathways and the placenta plays a crucial role. The paraoxonases (PONs 1–3) protect against oxidative damage and lipid peroxidation, modulation of endoplasmic reticulum stress and regulation of apoptosis. Nothing is known about the role of PON2 in the placenta and labour. Since PON2 plays a role in oxidative stress and inflammation, both features of labour, we hypothesised that placental PON2 expression would alter during labour. PON2 was examined in placentas obtained from women who delivered by cesarean section and were not in labour and compared to the equivalent zone of placentas obtained from women who delivered vaginally following an uncomplicated labour. Samples were obtained from 12 sites within each placenta: 4 equally spaced apart pieces were sampled from the inner, middle and outer placental regions. PON2 expression was investigated by Western blotting and real time PCR. Two PON2 forms, one at 62 kDa and one at 43 kDa were found in all samples. No difference in protein expression of either isoform was found between the three sites in either the labour or non-labour group. At the middle site there was a highly significant decrease in PON2 expression in the labour group when compared to the non-labour group for both the 62 kDa form (p = 0.02) and the 43 kDa form (p = 0.006). No spatial differences were found within placentas at the mRNA level in either labour or non-labour. There was, paradoxically, an increase in PON2 mRNA in the labour group at the middle site only. This is the first report to describe changes in PON2 in the placenta in labour. The physiological and pathological significance of these remains to be elucidated but since PON2 is anti-inflammatory further studies are warranted to understand its role.

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Influence of uterine contractions on the uteroplacental blood flow at term

Cited by 112 publications

References 7 publications

Asphyxia, Cerebral Palsy and Litigation

Asphyxia, Cerebral Palsy and Litigation

Mesometrial smooth muscle in the mouse: Its control of uterine blood flows

Paraoxonase 2 Protein Is Spatially Expressed in the Human Placenta and Selectively Reduced in Labour

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