Summary
Positive feedback between oxytocin and uterine contractions drives childbirth.
In depth
Stretching of the cervix increases oxytocin release (Ferguson reflex), uterus contracts more, forming a positive feedback loop. Prostaglandins ripen the cervix. The cycle stops after birth.
Labour has three stages. Pain relief options include epidural. Caesarean section is surgical delivery.
Key idea: oxytocin and contractions form a positive feedback loop.
Childbirth is driven by positive feedback. As the fetus matures, oestrogen rises relative to progesterone, increasing oxytocin receptors on the uterus, and fetal cortisol and prostaglandins contribute. When contractions push the baby's head against the cervix, stretch receptors signal the hypothalamus, causing the posterior pituitary to release oxytocin.
Oxytocin strengthens contractions, which increases pressure on the cervix, which releases more oxytocin, until the baby is born and the stimulus ends. Labour has three stages: cervical dilation, delivery of the baby, and delivery of the placenta. Relaxin loosens the pelvic ligaments.
Example: synthetic oxytocin is used to induce or speed labour and prevent haemorrhage.
Frequently asked questions
What is Parturition?
Positive feedback between oxytocin and uterine contractions drives childbirth.
Which area of biology covers Parturition, and how advanced is it?
Parturition is one of the 54 topics in Reproduction & Endocrinology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Pregnancy Hormones, Lactation, Positive Feedback.
Why does Parturition matter?
A classic example of positive feedback with a defined end point.
Can you give an example of Parturition?
Contractions increase from every 20 minutes to every 2 to 3 minutes.
What should I learn before Parturition?
Work through the Beginner topics in Reproduction & Endocrinology first, such as Reproduction, Asexual Reproduction, Sexual Reproduction, then return to Parturition. Intermediate topics assume the Beginner vocabulary.
What topics are related to Parturition?
The closest topics to Parturition are Pregnancy Hormones, Lactation, Positive Feedback, Hormonal Control of the Menstrual Cycle. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Parturition?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Parturition. To practise the whole of Reproduction & Endocrinology, use the Reproduction & Endocrinology quiz.
How is Parturition different from Pregnancy Hormones?
Parturition: Positive feedback between oxytocin and uterine contractions drives childbirth. Pregnancy Hormones: hCG maintains the corpus luteum early on, then the placenta produces progesterone and oestrogen. Read both side by side and note what each one explains.
How should I study Parturition step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Pregnancy Hormones and explain the difference aloud. Finally, take the Reproduction & Endocrinology quiz and come back to this page for any question you miss.