In Michigan, our traditional Medicaid asks for multiple deliveries billed as follows:
For twin gestation, report the service on two lines with no modifier on the first and modifier 51 on the second. If all maternity care was provided, report the global obstetric (OB) service for the first infant, and report the appropriate delivery-only code for the second infant using modifier 51. If multiple gestation for more than twins is encountered, report the first service on one line and combine all subsequent deliveries on the second line with modifiers 51 and 22. Provide information in item 19 or submit an attachment to the claim explaining the number of babies delivered.
It's really going to depend upon the insurance carrier guidelines. Most will offer them in the clinical policies or billing policies for multiple births when they have accessible online informatin.
Aetna's policy is to bill the single delivery/global care code and attach modifier 22, and realize Aetna may request supporting documentation after they receive the claim. Don't forget to increase your provider's charge on the delivery/global care code with modifier 22. It is possible to receive up to half of the allowed amount for the second delivery.
In addition, multiple gestations are always considered high-risk pregnancies. If your provider performs the antepartum care, I would recommend reviewing their documentation of OB visits and separately bill any appropriately documented visits after the thirteenth visit. You'll have to use high-risk pregnancy diagnosis codes, which you would be using all along anyway.
Hope this helps.