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Unlabelled: We discovered that the official list of clinical codes for pregnancy during the COVID-19 pandemic identified some unlikely pregnancies (for example, in older men), principally due to a code describing a specific fetal position ("knee presentation"), which notably lacks "fetal" in the code description. This is an informative example of commonly overlooked problems in creating and using clinical data.
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Curtis et al. (2026) studied this question.
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