O26.12 Low weight gain in pregnancy, second trimester

Billable ICD-10-CM code, FY2026.

MS-DRG index

Defines the logic of DRG(s) 817-819 in MDC 14.

Approximate ICD-9-CM (GEMs)

• 646.81 Other specified complications of pregnancy, delivered, with or without mention of antepartum condition (approximate)
• 646.83 Other specified complications of pregnancy, antepartum condition or complication (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Maternity diagnoses (age 9 through 64): Age conflict edit. These diagnoses are clinically expected only in patients age 9 through 64.

Code annotations containing back-references to O26.12

Back-references to O26

• Type 1 Excludes: Z03.7 Encounter for suspected maternal and fetal conditions ruled out ("known or suspected fetal anomalies affecting management of mother, not ruled out (O26.-, O35.-, O36.-, O40.-, O41.-)")

Nearby codes

• O26.02 Excessive weight gain in pregnancy, second trimester
• O26.03 Excessive weight gain in pregnancy, third trimester
• O26.1 Low weight gain in pregnancy
• O26.10 Low weight gain in pregnancy, unspecified trimester
• O26.11 Low weight gain in pregnancy, first trimester
• O26.12 Low weight gain in pregnancy, second trimester (this code)
• O26.13 Low weight gain in pregnancy, third trimester
• O26.2 Pregnancy care for patient with recurrent pregnancy loss
• O26.20 Pregnancy care for patient with recurrent pregnancy loss, unspecified trimester
• O26.21 Pregnancy care for patient with recurrent pregnancy loss, first trimester
• O26.22 Pregnancy care for patient with recurrent pregnancy loss, second trimester