Pregnant woman on ultrasound
Blog August 22, 2019

Coding Gestational Complications

Obstetrical coding can be challenging for most coders.  There are very specific rules that must be followed to properly assign all codes related to the obstetrical stay.  For pre-existing conditions and conditions due to pregnancy it’s important to be able to distinguish the difference. 

Most coders have a good understanding of gestational diabetes and hypertension because there are specific official coding guidelines for these particular conditions.  However, lesser-known conditions such as proteinuria, hyperemesis, thrombophlebitis and varicose veins are also conditions that could be due to pregnancy.    

Edema and proteinuria are coded to the O12 category in ICD-10-CM.  This category of codes is to be used when edema and or proteinuria are present without hypertension.   The cause of gestational proteinuria is unknown.  Close observation is warranted as it can progress to preeclampsia, a possible life-threatening condition. Indicators to look for in the documentation include increasing proteinuria as pregnancy progresses.  The gold standard for diagnosis is a urine protein value of 300mg per day (24-hour urine collection).  The alternative and still worthy of diagnosis is a 12-hour collection.  Another lab value to review is the protein-to-creatinine ratio with a result of >0.19 as this can also depict significant proteinuria.  A positive dipstick for protein in the urine is not enough to warrant the diagnosis of proteinuria as this result can be impacted by other factors such as hydration and exercise.  ICD-10-CM has code categories for gestational edema O12.0-, gestational proteinuria O12.1-, and a combination code for gestational edema with proteinuria O12.2-. 

Hyperemesis in pregnancy is assigned to the O21 category and is defined as excessive vomiting, severe dehydration, and weight loss.  This condition doesn’t typically harm the baby but does carry an increased risk of the baby being born smaller than expected.  Hyperemesis gravidarum usually starts between weeks 5 and 10 and most times resolves by week 20.  The O21 category also includes late vomiting in pregnancy which is defined as when excessive vomiting starts after the completion of 20 weeks.  Treatment includes IV fluids and medications to relieve nausea.

Venous complications related to pregnancy are assigned to the O22 category.  This category includes many different vascular complications.  Here is where we find: varicose veins, genital varices, superficial thrombophlebitis, deep phlebothrombosis, hemorrhoids, and central venous thrombosis. As mentioned earlier obstetrical coding has very specific guidelines so knowing when to assign an additional code from another chapter in ICD-10-CM is extremely important.  An example of this is superficial thrombosis and deep phlebothrombosis.  Each requires an additional code to specifically identify the site of disease.  Pregnancy complicated by DVT can be treated with anticoagulants because they do not cross the placenta. ICD-10-CM also instructs the coder to assign an additional code for long use of anticoagulants code Z79.01 if applicable.   

Understanding the specific guidelines associated with the obstetrical chapter is imperative for proper coding and reporting.  Our coders are provided both clinical and coding education through our LMS (learning management system) to help them understand these nuances and prevent the over-coding or under-coding commonly seen among inexperienced coders.  We have the workforce solutions to assist with all of your HIM coding needs.