Matched designs--intuitively attractive, but the analysis can be problematic.
Lett
Christine
C
Case
Allison
A
Baerwald
Angela
A
D000026:Abortion, Habitual / Q000453:epidemiology* / Q000517:prevention & control*; D000328:Adult; D001241:Aspirin / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D006801:Humans; D016555:Matched-Pair Analysis; D011241:Prednisone / Q000627:therapeutic use; D011247:Pregnancy; D011374:Progesterone / Q000627:therapeutic use*; D012107:Research Design
D011374:Progesterone; D005492:Folic Acid; D001241:Aspirin; D011241:Prednisone