Second stage of labour begins with
**Core Concept**
The second stage of labor is a critical period in the delivery process, characterized by the expulsion of the fetus from the birth canal. It marks the transition from the active phase of the first stage to the final stages of labor, where the mother's body prepares for the birth of the baby.
**Why the Correct Answer is Right**
The second stage of labor begins with the full cervical dilation, which is confirmed by the attending obstetrician. As the cervix is fully dilated, the mother starts to push the baby down the birth canal, a process facilitated by the pelvic floor muscles, including the pubococcygeus muscle and the anal sphincter. This stage is a crucial period of intense muscular effort, where the mother's body propels the baby through the birth canal.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because the first stage of labor is divided into three phases: early, active, and transitional. The second stage begins after the active phase of the first stage.
**Option B:** This is incorrect because the second stage of labor begins with full cervical dilation, not with the onset of contractions.
**Option C:** This is incorrect because the second stage of labor is characterized by the expulsion of the fetus from the birth canal, not by the presence of fetal distress.
**Clinical Pearl / High-Yield Fact**
A key aspect of the second stage of labor is the presence of the fetal head in the pelvis, which can be confirmed by a digital vaginal examination. This is a critical moment in the delivery process, where the mother's body prepares for the birth of the baby.
**Correct Answer:** C. Full cervical dilation.