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Heart-rate variation and movement incidence in growth-retarded fetuses with decelerative heart rate patterns. Correlations with fetal acid-base status
236
Heart-rate variation and movement incidence in growth-retarded fetuses with decelerative heart rate patterns. Correlations with fetal acid-base status
D.J. Bekedam and G.H.A. Visser, Department of Obstetrics and Gynaecologv, University Hospital of Groningen, The Netherlands
With progressive deterioration of the fetal condition both heart-rate variation and body movements decrease. From an earlier study of intrauterine growth-retarded fetuses (IUGR) it is known that, in the absence of late decelerations, heart-rate variation usually is within normal limits (Visser, 1984). The aim of this study is to gain more insight as to when heart-rate variation and movements decrease in the IUGR fetus, and furthermore to examine the relationship of these variables with the fetal acid-base status at delivery. Data will be presented of 18 IUGR fetuses of whom combined one-hour records of heart rate and body movements were obtained within 24-h of caesarean section (CS). Heart-rate records were analysed using a computer program (Dawes et al., 1981); body movements were observed by a real-time scanner (Aloka 256SD). Data from earlier studies on heart rate variation and movement incidence were used as a control. At delivery arterial and venous blood was sampled from the umbilical cord and analysed immediately by an automatic blood-gas analyser (RVL 940). Blood-gas values were compared to those of a control group of 30 elective CS, performed for reasons other than IUGR or intrauterine asphyxia. Assessed visually (Visser and Huisjes, 1977) 15 heart-rate patterns were decelerative and 3 terminal. Two of the infants with a terminal pattern died in utero. Baseline heart-rate variation fell below the normal range in 80% of the infants with a decelerative or terminal heart-rate trace. The fetal movement incidence was reduced in 14 of the 18 fetuses. The lowest movement incidence was found in the fetuses with a terminal heart-rate pattern. There was a slight, but significant, correlation of the movement incidence with the umb.art. pH (r = 0.53; P c 0.05). The mean umbilical artery pH (7.20) was significantly lower than that in the control group (7.27). In 7 of the 16 liveborn infants the umbilical artery pH fell below 1 S.D. (7.20) of the control group. The p0, values, however, were below normal in all but one of the infants. The mean art. p0, value was 1.63 kPa, compared to 2.92 kPa in the control group. This significant difference was independent of the umb. art. pH, as comparison of p0, values of infants with pH values in the same range (7.20-7.28) also revealed a significantly lower p0, in the IUGR group. It is concluded that: 1. Hypoxemia may play a larger role in the initial reduction of baseline heart-rate variation and movement incidence than acidemia. 2. Fetal movement incidence and heart-rate variation decline before acidemia develops; the movement incidence is, however, related to the PH... 3. Baseline heart-rate variation usually only falls below normal when late decelerations are present.
231
References Dawes, G.S., Visser, G.H.A., Goodman, J.D.S. and Redman, C.W.G (1981): Amer. 141.43-52. Visser, G.H.A. (1984): Aust. N.Z. J. Obstet. Gynaec.. in the press. Visser. G.H.A., Huisjes, H.J. (1977): Brit. J. Obstet. Gynaec., 84,5; 321-326.
J. Obstet.
Gynec.,
Morphogenetic properties of the cranial sutures
W.J. van Doorenmaalen, I.S. Markens and H.A.J. Oudhof, Department of Medical Anatomy and Embryology, University of Utrecht, Utrecht, The Netherlands
Cranial sutures are one of the mechanisms of growth in the skull. They have been considered as plain areas of appositional growth and skull bone connecting structures. However, studying the development of the skull in embryos of rat and human specimens, it was observed that in the area between the presumptive bones clearly separated condensations of mesenchymal cells were present. When this tissue was cultured at the onset of different ages, age-dependent properties were found. Apparently the tissue is programmed to follow a certain developmental course. The suturae were also studied postnatally, during which the growing of fingershaped extensions of bone was observed coming from the bony margins of the sutura. These extensions, named lingulae, fit into corresponding cavities in the opposite site of the bone, like a tooth in its alveolus. Fibers are formed which are arranged quite specifically; radiating out from the tips of the lingulae and running obliquely, away from the tips, from the slopes into the walls of the cavity, preventing the lingula moving deeper into its fossa. The fibers are interwoven with the periostea and some extend into the bone tissue as Sharpey fibers. This fiber arrangement is just like the fixation of a tooth. The lingulae, causing the sutura serrata at the outer side of the skull, decrease in length gradually to the inner side. They are lacking on a small area at the inner side, causing a sutura plana. There the bones are connected by a fibrous band. The fibrous arrangement suggested a mechanical function, probably limiting movements of the skull bones, the site of the ligament at the inner side being the axis. To investigate this theory, autotransplantations were done in the rat. A transplant, consisting of the bregma where the two sut. coronales and the sut. sagittalis and interfrontalis come together, was transplanted within the OSparietale, because of which mechanical influences were excluded. It was found that the transplant became fixed into the parietal bone by osseous growth. The suturae, however, disintegrated; the specific fibrous structures were exchanged for loose connective tissue and lingulae decreased in length and in number. In the reverse experiment a piece of OS parietale was transplanted into the bregma. In the phase of rapid growth only fusion to the frontal bones occurred, whereas the transplantation slit on the parietal side remained open and in continuity
Heart-rate variation and movement incidence in growth-retarded fetuses with decelerative heart rate patterns. Correlations with fetal acid-base status
D.J. Bekedam and G.H.A. Visser, Department of Obstetrics and Gynaecologv, University Hospital of Groningen, The Netherlands
With progressive deterioration of the fetal condition both heart-rate variation and body movements decrease. From an earlier study of intrauterine growth-retarded fetuses (IUGR) it is known that, in the absence of late decelerations, heart-rate variation usually is within normal limits (Visser, 1984). The aim of this study is to gain more insight as to when heart-rate variation and movements decrease in the IUGR fetus, and furthermore to examine the relationship of these variables with the fetal acid-base status at delivery. Data will be presented of 18 IUGR fetuses of whom combined one-hour records of heart rate and body movements were obtained within 24-h of caesarean section (CS). Heart-rate records were analysed using a computer program (Dawes et al., 1981); body movements were observed by a real-time scanner (Aloka 256SD). Data from earlier studies on heart rate variation and movement incidence were used as a control. At delivery arterial and venous blood was sampled from the umbilical cord and analysed immediately by an automatic blood-gas analyser (RVL 940). Blood-gas values were compared to those of a control group of 30 elective CS, performed for reasons other than IUGR or intrauterine asphyxia. Assessed visually (Visser and Huisjes, 1977) 15 heart-rate patterns were decelerative and 3 terminal. Two of the infants with a terminal pattern died in utero. Baseline heart-rate variation fell below the normal range in 80% of the infants with a decelerative or terminal heart-rate trace. The fetal movement incidence was reduced in 14 of the 18 fetuses. The lowest movement incidence was found in the fetuses with a terminal heart-rate pattern. There was a slight, but significant, correlation of the movement incidence with the umb.art. pH (r = 0.53; P c 0.05). The mean umbilical artery pH (7.20) was significantly lower than that in the control group (7.27). In 7 of the 16 liveborn infants the umbilical artery pH fell below 1 S.D. (7.20) of the control group. The p0, values, however, were below normal in all but one of the infants. The mean art. p0, value was 1.63 kPa, compared to 2.92 kPa in the control group. This significant difference was independent of the umb. art. pH, as comparison of p0, values of infants with pH values in the same range (7.20-7.28) also revealed a significantly lower p0, in the IUGR group. It is concluded that: 1. Hypoxemia may play a larger role in the initial reduction of baseline heart-rate variation and movement incidence than acidemia. 2. Fetal movement incidence and heart-rate variation decline before acidemia develops; the movement incidence is, however, related to the PH... 3. Baseline heart-rate variation usually only falls below normal when late decelerations are present.
231
References Dawes, G.S., Visser, G.H.A., Goodman, J.D.S. and Redman, C.W.G (1981): Amer. 141.43-52. Visser, G.H.A. (1984): Aust. N.Z. J. Obstet. Gynaec.. in the press. Visser. G.H.A., Huisjes, H.J. (1977): Brit. J. Obstet. Gynaec., 84,5; 321-326.
J. Obstet.
Gynec.,
Morphogenetic properties of the cranial sutures
W.J. van Doorenmaalen, I.S. Markens and H.A.J. Oudhof, Department of Medical Anatomy and Embryology, University of Utrecht, Utrecht, The Netherlands
Cranial sutures are one of the mechanisms of growth in the skull. They have been considered as plain areas of appositional growth and skull bone connecting structures. However, studying the development of the skull in embryos of rat and human specimens, it was observed that in the area between the presumptive bones clearly separated condensations of mesenchymal cells were present. When this tissue was cultured at the onset of different ages, age-dependent properties were found. Apparently the tissue is programmed to follow a certain developmental course. The suturae were also studied postnatally, during which the growing of fingershaped extensions of bone was observed coming from the bony margins of the sutura. These extensions, named lingulae, fit into corresponding cavities in the opposite site of the bone, like a tooth in its alveolus. Fibers are formed which are arranged quite specifically; radiating out from the tips of the lingulae and running obliquely, away from the tips, from the slopes into the walls of the cavity, preventing the lingula moving deeper into its fossa. The fibers are interwoven with the periostea and some extend into the bone tissue as Sharpey fibers. This fiber arrangement is just like the fixation of a tooth. The lingulae, causing the sutura serrata at the outer side of the skull, decrease in length gradually to the inner side. They are lacking on a small area at the inner side, causing a sutura plana. There the bones are connected by a fibrous band. The fibrous arrangement suggested a mechanical function, probably limiting movements of the skull bones, the site of the ligament at the inner side being the axis. To investigate this theory, autotransplantations were done in the rat. A transplant, consisting of the bregma where the two sut. coronales and the sut. sagittalis and interfrontalis come together, was transplanted within the OSparietale, because of which mechanical influences were excluded. It was found that the transplant became fixed into the parietal bone by osseous growth. The suturae, however, disintegrated; the specific fibrous structures were exchanged for loose connective tissue and lingulae decreased in length and in number. In the reverse experiment a piece of OS parietale was transplanted into the bregma. In the phase of rapid growth only fusion to the frontal bones occurred, whereas the transplantation slit on the parietal side remained open and in continuity