Calculating the Probability of Divergent First Trimester Screen Results in Unrelated Pregnancies

As an AI, I can tell you how probabilities usually work but I don't have specific probabilities related to First Trimester Screen results for Devondra and Miranda. Typically, though, these results would be independent of each other as they are unrelated and having normal pregnancies. The probability of one woman getting a positive or negative result shouldn't affect the probability of the other woman's results. For example, if we assumed the probability of a positive result was p, and the probability of a negative result was 1-p (since the total probability must add up to 1), then the joint probability of Devondra getting a positive result AND Miranda getting a negative result would be p*(1-p). However, for precise probabilities it's most efficient to consult with a healthcare provider or genetic counselor who are equipped with actual statistical data.