O26.13 — Low weight gain in pregnancy, third trimester
O26.13 is a billable, specific ICD-10-CM code for low weight gain in pregnancy, third trimester. It is valid for submission on a claim.
Other codes that can never be billed with O26.13
These codes carry an Excludes1 note pointing at O26.13. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading O26.13 alone.
- Z03.7Encounter for suspected maternal and fetal conditions ruled out
Risk adjustment
O26.13 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
O26.13 is named in 1 Medicare coverage policy — 1 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A57189Billing and Coding: Serum Magnesium
Code history
O26.13 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.
Related codes at this level
Codes that share O26.1. If O26.13 is not quite right, the correct code is usually one of these.
Questions about O26.13
- Is O26.13 a billable ICD-10-CM code?
- Yes. O26.13 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does O26.13 sit in the tabular list?
- Pregnancy, childbirth and the puerperium (O00-O9A), in the block Other maternal disorders predominantly related to pregnancy (O20-O29).