Biomedical subjects
S K Rosevear
Publications and source records attributed to S K Rosevear.
Smoking and decreased fertilisation rates in vitro.
To examine possible mechanisms for the association between cigarette smoking and reduced fertility, we have measured the concentration of the nicotine metabolite cotinine in ovarian follicular fluid collected at the time of oocyte recovery during treatment for in-vitro fertilisation. In a group of women in whom follicular fluid cotinine could not be detected (limit of accurate measurement 20 ng/ml) 116 oocytes were collected, of which 84 became fertilised (72%), whereas among women with cotinine concentration greater than 20 ng/ml 20/45 (44%) oocytes did so (p < 0.01). The median fertilisation rates for individuals (range 1-8 eggs each) in the high and low cotinine groups were 57% and 75%, respectively (p < 0.05). These findings suggest that infertile women should be advised to stop or reduce smoking generally, and especially before treatment by in-vitro fertilisation.
Computerized analysis of episodic changes in fetal heart rate variation in early labor.
Fetal heart rate variation in early labor was measured by computerized analysis in cyclic episodes of low or high variation in 136 women at 37 to 42 weeks' gestation. The amplitude (mean +/- SE) in episodes of low variation was 20.6 +/- 0.4 milliseconds; in high variation it was 57.3 +/- 1.1 milliseconds. The duration (mean +/- SE) of low episodes (24.3 +/- 1.3 minutes) was less than that of high episodes (45.1 +/- 2.7 minutes) but was sometimes greater than 1 hour. In episodes of low variation the amplitude was less than 5 beats/min long term in 11% and less than 2.5 milliseconds (pulse intervals) short term in 8%; these measures would be predictive of intrauterine death if persistent before birth. We conclude that the use of decreased fetal heart rate variation as a diagnostic sign of acute fetal hypoxemia in labor is incorrect, because changes of this size occur randomly as a consequence of fetal sleep states. There was no significant correlation between fetal heart rate variation over the last hour of labor and umbilical arterial base deficit on delivery.
Computerized fetal heart rate analysis in labor.
Observer variation in visual analysis of fetal heart rate (FHR) records is reportedly high, but can be avoided by computerized numerical analysis. The FHRs of 394 women in labor at 37 or more weeks' gestation were recorded on-line and analyzed to examine how different patterns related to outcome, as judged by umbilical arterial base deficit or Apgar score on delivery. The range of normality and the diversity of patterns of those delivered without acidemia were great. Late decelerations were of poor prognostic value. There was an increase in FHR variation during labor averaging 40%. In this preliminary study, conventional attributes of the FHR, alone or in combination, did not predict metabolic acidemia. Epidural analgesia in 240 women was identified as a confounding variable that significantly affected FHR patterns without influencing the condition of the infant at birth. It was associated with a higher FHR, less FHR variation and fewer decelerations, primiparity, longer labors, more operative deliveries, and a threefold greater cesarean rate. The rise in basal FHR, perhaps due to a rise in maternal temperature, may partly explain the high intervention rate in those without fetal acidemia.
Favourable neonatal outcome following maternal paracetamol overdose and severe fetal distress. Case report.
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Mechanism of action of the oxytocin antagonist 1-deamino-2-D-Tyr-(OEt)-4-Thr-8-Orn-oxytocin.
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Placental biopsy.
There is increasing patient demand for placental biopsy, principally for karyotyping because it enables termination of pregnancy in the first trimester if an abnormality is detected. Precise risks in terms of fetal loss rates due to the procedure have not been clearly established. Over 41,000 biopsies have been performed worldwide, with an average fetal loss rate of 3.54%.
Mosaic trisomy 7 confined to the placenta.
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Platelet dimensions in pregnancy-induced hypertension.
Platelet number, mean platelet volume (MPV) and platelet distribution width (PDW) were measured in 55 women admitted consecutively during four months from January-April 1984 with pregnancy-induced hypertension. The criteria for diagnosis were a sustained diastolic blood pressure greater than 90 mmHg during the first 24 h after admission, normal blood pressure recordings in the first trimester and a plasma urate value exceeding 0.34 mmol/l. The values were grouped according to gestation length and compared with those in a control group of 96 women of similar gestation lengths who were normotensive. Both MPV and PDW were significantly greater in the hypertensive group whereas platelet numbers did not differ. It is concluded that measurement of MPV and PDW is a useful diagnostic criterion of pregnancy-induced hypertension.