Coder Q&A: Coding for Newborn

Is a newborn at 40 weeks 0 day considered post term in coding?


Please advise on the appropriate  code for a newborn that is born at 40 weeks and 0 days. I’ve reviewed AHA Coding Clinic regarding gestational age and didn’t find one that specifically addressed if an infant born at 40w0days would be considered post-term and code P08.21,  assigned. Per the ICD-10- Handbook, post term is defined as:

“Post-term is defined as gestational period of more than 40 completed weeks to 42 completed weeks. Prolonged gestation or post-maturity is defined as a gestational period of more than42 completed weeks” 

There seems to be differences of opinions on the issue of a 40w0day gestation  Can you clarify if P08.21 should be assigned for 40w0day infant or if it would not be assigned unless the infant’s gestation age was 40w1day or greater?


I am taking the strict definition of “more than” 40 weeks.  40 weeks is not “more than” 40 weeks, it *is* 40 weeks.  So, the baby is not post term until after 40 completed weeks (more than 40 weeks such as 40/1 or any documentation that states the baby is over 40 weeks.)

P08.2 Late newborn, not heavy for gestational age

P08.21 Post-term newborn

Newborn with gestation period over 40 completed weeks to 42 completed weeks

P08.22 Prolonged gestation of newborn

Newborn with gestation period over 42 completed weeks (294 days or more), not heavy- or large-for-dates.

Post maturity NOS

O48 Late pregnancy

O48.0 Post-term pregnancy

Pregnancy over 40 completed weeks to 42 completed weeks gestation

O48.1Prolonged pregnancy

Pregnancy which has advanced beyond 42 completed weeks gestation

See also Coding Clinic, Fourth Quarter 2003 Page: 69  Late Infant as it states “…identifies post-term pregnancy as those patients whose pregnancies are between 40 and 42 weeks.

We know that every case is unique. The above post is simply our opinion based on the information we have received. We encourage readers to research subsequent official guidance in the areas associated with this topic as they can change rapidly.

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