Total Amount of Hæmoglobin and Physical Working Capacity in Normal Pregnancy and Puerperium (With Iron Medication)

Gemzell, Carl A.; Robbe, Hjördis; Ström, Gunnar

doi:10.3109/00016345709158026

Cited by 27 publications

(7 citation statements)

References 61 publications

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“…The leading cause for this is believed to be an increased vessel diameter in conjunction with an insufficient adaptation of the vascular autoregulation. Vasodilation during early pregnancy is supported by the trophoblastic invasion, estrogen and progesterone mediated relaxation of the venous smooth muscle tone, a reduced tone of the striated muscles and a marked shift in the production of prostaglandin derivatives from thromboxane to vessel dilating prostacyclin [2,8,10,11,12,15,24,25].…”

Section: Introductionmentioning

confidence: 99%

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The implication of upright posture on pregnancy

Schneider

Deckardt²

1991

Jpme

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Pregnant women spend more than half of the day in an upright position. The physiological effects of this posture on the mother and the fetus are evaluated. Changes in vascular autoregulation and anatomy lead to maternal fainting in about 8% of women during early pregnancy. The immediate effects of such episodes on the fetus are unknown. There is a positive correlation of orthostatic dysregulations and abortions. In late pregnancy we found a significant increase in functional residual capacity in the upright posture. Minute volume and oxygen consumption were also significantly increase (p less than 0.001). Regarding the cardiovascular changes we detected a rhythmic change of the maternal heart rate with the change to upright position, which had not been published before. Change from the left lateral position to unsupported standing increased maternal heart rate by a mean of 27 beats per minute and a mean duration of 105 seconds in two thirds of the women. This was accompanied by a decreased cardiac output, systolic blood pressure and an increased oxygen consumption. The gravid uterus is responsible for these changes. During the upright position, the venous flow to the right ventricle is inhibited by the relaxed uterus. Contractions, leaning forward and the muscle pump improve the venous return. The phenomenon reached its maximum during the 38th week, where 71% of pregnant women displayed a cyclic change in heart rate. The fetal heart rate baseline is significantly increased in the upright position with a significantly reduced acceleration frequency (p less than 0.001). Combined with the data from epidemiologic studies, prolonged standing during late pregnancy may signal potential risks for the fetus such as low birth weight, prematurity and stillbirths because of an 'uterovascular syndrome'. Maternal standing possibly may be used as a physiological fetal stress test.

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Section: Introductionmentioning

confidence: 99%

“…From published works it can be calculated that about 8% of women experience dizziness in early pregnancy after standing for 8 to 10 minutes and are not able to stand any longer. A reduction in systolic blood pressure by more than 20 mmHg and an increased heart rate can be observed in most of these cases [10,12,15,24].…”

Section: Introductionmentioning

confidence: 99%

The implication of upright posture on pregnancy

Schneider

Deckardt²

1991

Jpme

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“…It is known that the pregnancy itself leads to a number of cardiovascular changes (Bridgen et al 1950;Dahlstrom & Ihrman 1960;Gemzel et al 1957;Hytten & Leitch 1971;Ihrman 1960;Widlund 1945) which are especially seen in the supine and upright position (Bridgen et al 1950;Gauer & Thron 1965;Kerr et al 1964;Pyorala 1966;Quilligan &Tyler 1959;Secher et al 1973;Schneider et al 1983;Ueland & Hansen 1969).…”

mentioning

confidence: 99%

The oscillating ‘vena cava syndrome’ during quiet standing—an unexpected observation in late pregnancy

Schneider

Bollinger

Huch

et al. 1984

BJOG

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Summary. While studying the lung function of pregnant women at term in four different postures, we were surprised to note marked cyclic accelerations in the heart rate in two‐thirds of the women when in a standing position. The mean cycle length was 105 s (range: 1–4 min) and the amplitude had a mean of 27 beats/min (range: 9–51). Blood flow velocity measurements with ultrasound Doppler over the femoral vein showed that there was an intermittent reduction of flow during quiet standing. When the venous return ceased, maternal heart rate increased, cardiac output decreased and blood pressure fell. After the venous blood flow was restored, maternal heart rate, cardiac output and blood pressure returned to normal until the cycle started again. Concomitant with these maternal heart rate changes, different patterns of fetal heart rate were observed. About 70% of the fetuses showed reduction in the long‐term variability, increase in fetal heart rate or periodic accelerations. Although no woman fainted during quiet standing, the maternal circulatory changes were consistent with those seen in the classical vena cava syndrome.

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“…1086). PWC,,,, has been found to remain unchanged during pregnancy (Dahlstrom & Thrman 1960a, 1960bGemzell et al 1957;Soiva et al 1963), to decrease (Sandstsom 1974), or to bc comparable with values in a non-prcgnant sample (Dibblee & Graham 1983;Erkkola 1975). One could be tempted to summarize thcse inconsistent findings by postulating that physical work capacity is…”

Section: Exercise and Pregnancymentioning

confidence: 98%