Note: This category is provided for use when it is required to classify separately the complications classifiable to the fourth digit level in categories 634-638; for example:

a) when the complication itself was responsible for an episode of medical care, the abortion, ectopic or molar pregnancy itself having been dealt with at a previous episode

b) when these conditions are immediate complications of ectopic or molar pregnancies classifiable to 630-633 where they cannot be identified at fourth digit level.