In simple words: This code indicates that the pregnancy is either less than 10 weeks along or the exact number of weeks is unknown. It's used to track the mother's health during pregnancy.

Weeks of gestation of pregnancy, unspecified or less than 10 weeks. This code is used only on the maternal record to indicate the weeks of gestation, if known. Code first the obstetric condition or encounter for delivery (O09-O60, O80-O82).

Example 1: A pregnant woman presents for her first prenatal visit. The pregnancy is confirmed via ultrasound but is less than 10 weeks, so Z3A.0 is used., A woman presents to the ER with abdominal pain. A urine test confirms pregnancy, however, she does not know how far along she is. She is given an ultrasound and weeks of gestation are unspecified, so Z3A.0 is coded., A woman at six weeks gestation comes to the clinic for routine prenatal care. Z3A.0 is used to indicate the stage of her pregnancy.

Documentation should include the estimated gestational age based on the last menstrual period (LMP), ultrasound findings, or clinical estimation.

** Z codes are used to document reasons for encounters with healthcare providers when a disease or injury may or may not be present. A procedure code should accompany a Z code if a procedure is performed.As of November 30, 2024, this information is current but may be subject to change with updates to ICD-10 coding guidelines.