No, sqad, it is of course you who are spot on. I wasn't quite. I was using the commoner (and prob less medical) expression 'prima gravida' or 'primagravida' (total of 63,690 hits on Google vs 58,000 for 'primigravida').
If indeed it is 'less medical', that is no doubt because it�s
wrong! Obviously I am not as medical as I thought. I don't think I had seen 'primigravida' before, or if I had, I hadnt noticed the difference, though with my eagle eyes that is unlikely. (The eyes are getting ever less aquiline, however, as I complained
here , incurring an extraordinary attack, followed by wranglings which may amuse you.)
It�s wrong because it means �first pregnant woman� rather than �woman pregnant for the first time�, for God�s sake. How can it be so common, even outside medical literature? Because people like me use it without thinking, is why. What a disgrace! And me a trained classicist. 'Primigravida' is of course parallel to and analogous with �primipara�, and actually synonymous with it, or as nearly so as it�s possible to get without going into maths or something!
Now that you have (so unobtrusively, as opposed to the farrago I have linked to above) put me right, I shall of course follow your lead and use the spelling with i. Moreover I
shall no doubt be seeing it now that I have noticed it.
But you still don�t explain the �p of �primip�. Playful elaboration I suppose. Self-explanatory, really!