Provide summariazation transformation for the cohort

[mrhorvath]

some summary information about the AMMI data mart? e.g., how many births, how many of those resulted in pre-eclampsia? How many clinical fields, lab values, etc. (i.e., number of features altogether) are there? Are there other non-desirable end-points (e.g., death -of the mother or the baby, sepsis, etc.)