Final answer:
During a vaginal examination, dilation is measured in centimeters; effacement as a percentage of cervical thinning; and station is the baby's head position relative to the pelvis, measured on a scale from -5 to +5. These assessments are critical during the first stage of labor before the baby and placenta are expelled.
Step-by-step explanation:
To determine dilation, effacement, and station during a vaginal examination, healthcare providers assess the following:
- Dilation: Measured in centimeters, dilation refers to the opening of the cervix, which must fully dilate to 10 cm to allow passage of the newborn's head.
- Effacement: This is the thinning of the cervix, expressed as a percentage from 0% (not effaced) to 100% (fully effaced).
- Station: This represents the position of the baby's head relative to the ischial spines of the pelvis. It's measured on a scale from -5 to +5, where 0 indicates the head is level with the ischial spines.
These assessments are integral parts of the first stage of labor, which is characterized by the cervix thinning and dilating, generally taking 6-12 hours but can vary greatly. The second stage involves the expulsion of the baby from the uterus, and the third stage is the delivery of the placenta.