Correlation between the foetal acid-base status and the Apgar score

The foetal pH values of eighty-eight cases delivered within 30 min after foetal blood sampling were correlated with the 1-min Apgar score. With a pH of 7·20 or above the error of prediction was 1·3%. The error in cases with pH below 7·20 was 54·5%.

Significantly higher pH and lower δ base deficit were present in the low foetal pH group in vigorous, as opposed to depressed infants, suggesting that infusion acidosis was present in infants with a high Apgar score.

The degree of correlation between the foetal pH and the Apgar score was not significantly influenced by shortening the sampling-delivery interval to 15 min or lengthening it to 3 hr. The most significant factor affecting the degree of correlation in the present study was the setting of the critical pH. If the criterion of the critical pH was taken as 7·13 there would have been no false positive results and the error of prediction in cases delivered within 30 min of foetal blood sampling would be reduced to 1·1%.

Foetal acid-base status in clinical foetal distress and high risk cases

The acid-base balance in 307 Chinese patients in labour was studied in Tsan Yuk Hospital, Hong Kong over a 15-month period. Fifty-six of these were normal cases, 200 cases exhibited clinical signs of foetal distress and the other fifty-one were high risk cases. The results showed that cases of clinical foetal distress had a significantly lower foetal pH than that in the normal control group. Of the different signs of clinical foetal distress, meconium was the least important and foetal tachycardia appeared to be more significant than the others. Cases of postmaturity and uterine inertia also gave a lower foetal pH than normal. It is concluded that foetal blood sampling is indicated in these types of cases.

Effects of chondroitin sulphates on mineralization in vitro

1. Soluble sodium chondroitin sulphate, from bovine ribs or puppy epiphyseal plate, at a concentration 80mm in terms of glucuronate, decreased the amounts of calcium and phosphate precipitated from a solution 6.9mm in phosphate and 6.9 or 13.8mm in calcium, buffered in the pH range 6.6-8.2 with 20-25mm-collidine and 5-20mn-hydrochloric acid when incubated for 2hr. at 30 degrees , and for 0.25-24hr. when buffered at pH7.0. 2. An insoluble fraction of puppy epiphyseal plate, containing chondroitin sulphate and collagen, was found to have the same effect at lower concentrations of chondroitin sulphate and a higher calcium/chondroitin sulphate glucuronate ratio, but the formation of calcium phosphate from calcium bound to this material appeared to proceed more rapidly than from calcium in solution, when both were present in the same system. 3. The implications of these results are discussed in relation to the calcium/chondroitin sulphate glucuronate ratios found in different parts of non-calcifying and calcifying cartilage in vivo and to the calcium and phosphate gradients between blood and calcified tissue.