Final answer:
The nurse is documenting that the woman is in the first stage of labor since the cervix is dilated to 9 cm. The second stage will commence once full dilation of 10 cm is reached and the baby is expelled.
Step-by-step explanation:
When the nurse assesses a woman in labor and finds that her cervix is dilated to 9 cm, she is documenting that the woman is in the first stage of labor. The first stage of labor consists of the cervix thinning and dilating and is categorized into two phases: early labor, when the dilation is from 0 to 4 cm, and active labor, when dilation expands from 4 to 10 cm.
The second stage of labor begins once the cervix is fully dilated to 10 cm and continues until the baby is expelled from the uterus. Finally, the third stage involves the passage of the placenta after the baby has been born.