What makes labor start?

Answer 1

Oh that's a fun one...alot of things are said to help, things like spicy foods, walking, castor oil and things like that, but the most likely thing to work is what Doctors recomend and that's sex.

Answer 2

There are a lot of different factors... but here's one of the major things that happens hormonally between baby and mother to initiate labor.

Cortisol from the baby's adrenal glands rises towards term, reducing the amount of progesterone released by the placenta, and increasing production of estrogen. High estrogen levels cause more oxytocin receptors to appear on the uterine muscle cell membranes by the mother. Oxytocin is then released in higher quantities by the mom's pituitary gland, simulating the uterus to contract.

In addition, there are studies that a protein is released when the baby's lungs are mature enough for transition to extra-uterine breathing. And that also helps to initiate uterine contractions and labor.

Answer 3

When the baby's lungs are fully developed they inhale some of the amniotic fluid. This then causes a protein to be released into the fluid which starts labour.