parturition

Question

Which factor significantly increases uterine contractions near term?

RankGuru · Accepted Answer

1. **Parturition Mechanism**: The process of childbirth is induced by a complex neuroendocrine mechanism.
2. **Hormonal Shift**: Toward the end of pregnancy, the ratio of estrogen to progesterone rises.
3. **Receptor Regulation**: High estrogen levels cause the uterine muscle (myometrium) to increase its **sensitivity to oxytocin** by synthesizing more oxytocin receptors.
4. **Positive Feedback**: Uterine contractions stimulate the fetal ejection reflex, leading to more oxytocin release from the maternal posterior pituitary, which in turn causes stronger contractions.
5. **Prostaglandins**: These also increase (not decline) to soften the cervix and enhance contractions.

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parturition

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