When coding for an obstetric patient, the presence of multiple gestation is always coded because it’s a condition that is considered to complicate the pregnancy. Multiple gestation is reported with an ICD-10-CM code from category O30 Multiple Gestation. Codes from this category describe the type of multiple gestation in terms of the combination of chorions/placenta(s) and amniotic sac(s) the make up the pregnancy. When describing multiple gestation types, the number of chorions/placentas is referenced first, followed by the number of amniotic sacs.
Only twin multiple gestations are covered in this Coding Tip, but the same principles apply to coding for multiple gestations of three or more fetuses.
Familiarity with the following terms is essential to understanding the specific placenta/amniotic sac combinations that occur in twin gestations.
Chorion – Outer membrane that surrounds the amnion, the fetus and other membranes in the uterus and contributes to the growth of the placenta
Amnion – Thin, tough membrane that lines the amniotic cavity and holds the amniotic fluid and developing fetus.
Mo/Mono – One
Di – Two
Mono/Di chorionic – One/two/three placentas
Mono/Di amniotic – One/two/three amniotic sacs
There are three different types of twin pregnancy. Each type is identified based on the number of chorions/placentas and the number of amniotic sacs that are involved between two fetuses.
Dichorionic diamniotic (DiDi)
Monochorionic diamniotic (MoDi)
Monochorionic monoamniotic (MoMo)
ICD-10-CM category O30 has codes for reporting any configuration of multiple gestation. Coding for twin pregnancies is the focus of this discussion.
Twin pregnancy
Subcategory O30.0 includes the codes for pregnancies comprised of two fetuses. Assignment of these codes is pretty straightforward as it follows the terms presented previously. The 5th character of the code indicates the combination of chorions/placentas and amniotic sacs.
Subcategory O30.0 also includes
When selecting among these codes, remember
All codes from category O30 require the addition of a 6th character identifying which trimester of pregnancy the patient is in during the encounter being coded.
A 27 yr. old patient is seen at 30 weeks gestation for an OB ultrasound. The findings of the ultrasound show both fetuses having their own amniotic sac but sharing a placenta.
ICD-10-CM code: O30.032 Twin pregnancy, monochorionic/diamniotic, second trimester
This is a monochorionic pregnancy because there is only one placenta shared between two fetuses and a diamniotic pregnancy because there are two amniotic sacs, one for each fetus.
The correct 6th character is “2” because 26 weeks of gestation falls into the second trimester of pregnancy.
For expanded information on how to code multiple gestation pregnancies, including instruction on how to code for pregnancies with three or more fetuses and additional case studies, see our eBook ICD-10-CM Coding for Multiple Gestations.
References
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The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.