Correct assignments for hypertension
For correct code assignment, it is important to determine whether the hypertension is a pre-existing or a gestational condition.
Pre-existing hypertension is classified to category O10, Pre-existing hypertension complicating pregnancy, childbirth and the puerperium, as follows:
O10.01–O10.03 Pre-existing essential hypertension complicating pregnancy
O10.111–O10.13 Hypertensive heart disease
O10.211–O10.23 Hypertensive chronic kidney disease
O10.311–O10.33 Hypertensive heart and chronic kidney disease
O10.411–O10.43 Secondary hypertension
O10.911–O10.93 Unspecified
When assigning one of the O10 codes that includes hypertensive heart disease or hypertensive chronic kidney disease, it is necessary to add a secondary code from the appropriate hypertension category to specify the type of hypertensive heart disease (category I11), heart failure (category I50), chronic kidney disease (category I12), or hypertensive heart and chronic kidney disease (category I13).
Patients who do not have pre-existing hypertension may develop transient or gestational or pregnancy-induced hypertension during pregnancy. This condition is coded to category O13, Gestational [pregnancy-induced] hypertension without significant proteinuria.
O13.X Gestational [pregnancy-induced] hypertension without significant proteinuria. X refers to the trimester (1, 2, or 3, or 9 if unspecified)
Hypertension in pregnancy sometimes leads to preeclampsia or eclampsia. When preeclampsia is superimposed on a pre-existing hypertension, a code from category O11 with an additional code from category O10 to identify the type of hypertension are assigned.
O11.X Pre-existing hypertension with pre-eclampsia. X refers to the trimester (1, 2, or 3, or 9 if unspecified)
When preeclampsia arises without any pre-existing hypertension, it is classified in category O14, Pre-eclampsia.
O14.0X Mild/moderate pre-eclampsia. X refers to the trimester (2, or 3; or 0 if unspecified)
O14.1X Severe pre-eclampsia. X refers to the trimester (2, or 3; or 0 if unspecified)
O14.2X HELLP Syndrome. X refers to the trimester (2, or 3; or 0 if unspecified)
O14.9X Unspecified pre-eclampsia. X refers to the trimester (2, or 3; or 0 if unspecified)
Eclampsia, regardless of whether it is due to pre-existing hypertension, gestational hypertension, or unspecified material hypertension, is classified to category O15, Eclampsia.
O15.0X Eclampsia in pregnancy. X refers to the trimester (2, or 3; or 0 if unspecified)
O15.1 Eclampsia in labor.
O15.2 Eclampsia in the purperium.
O15.9 Eclampsia, unspecified as to time period.
Although uncommon, preeclampsia can occur in the postpartum period. A specific ICD-10 code is not available, so we suggest assigning codes O90.89, Other complications of the puerperium, not elsewhere classified, and I15.8, Other secondary hypertension, to describe postpartum preeclampsia without mention of a pre-existing hypertension.
When gestational edema, gestational proteinuria, or both, are present without hypertension, these conditions may be classified to category O12, Gestational [pregnancy-induced] edema and proteinuria without hypertension.
O12.0X Gestational edema. X refers to the trimester (1, 2, or 3; or 0 if unspecified)
O12.1X Gestational proteinuria. X refers to the trimester (1, 2, or 3; or 0 if unspecified)
O12.2X Gestational edema & proteinuria. X refers to the trimester (1, 2, or 3; or 0 if unspecified)