Patient is seen for PP care after deliver. We perform a 87210 and our coding department entered N89.8 and ties this to 87210 but then enters Z48.816 as another DX on the claim. Should the Z48.816 also be linked to 87210 or not? Or should it just be listed on the claim or not listed at all?

Patient is 28 weeks pregnancy and a flu shot is given to patient. Does the weeks of gestation need to be added to claimZ3A.28? 90686 and 90471 with Z23.
Or would this be a third party of Medicaid carrier discretion?