How Does The Baby Know When To Be Born?

It's countdown to birth and the anticipation can throw a person into some serious thinking.  Especially the first time around, when you have no idea what it's supposed to look like.  But then, it turns out, I'm not the only one with questions.  I was driving in the car with my father today and he says to me: "you know, I've never really thought of it before, but how does the baby know when to be born?"  I laughed, because this question has been plaguing me for the past few days.  What is it that we are waiting for??  I asked my mother later if she knew, and she couldn't come up with any real answer.  So, being the "googler" that I am, I began to look for the answers.

Once you're pregnant, and assuming you read a few books, take a childbirth education class, or ask your doctor questions, you begin to learn that there are signs that will tell you labor is imminent.  You start "nesting" or "carb-loading."  If you are allowing your doctor/midwife to check your cervix in those last few weeks, signs of your cervix effacing (thinning) and dilating (opening) will give you some clues that things are hopping into gear.  Losing your uterine seal (commonly called the mucous plug), or the pinkish/brownish discharge of your birth show (commonly called the bloody show) will also be fluid signs that you may be going into labor.  Finally, if your membranes release (commonly called "your water breaks"), then you have definitely reached the stage of imminent birth.  And, unlike the movies, less than ten percent of women experience membrane release before their labor contractions begin, so at that point, you've probably already gone into labor and are very aware of it.  However, none of this tells you why or how the baby has decided to come out, and it certainly wasn't a conscious decision on your part (or it probably would have happened sooner)!  So, how does it happen?

It looks like, as far as science knows thus far, the full story is pretty much a mystery.  However, there is one part of it that we have discovered.  According to researchers at UT Southwestern Medical University in Dallas, the development of a specific fetal lung protein signifies to the mother's body that the lungs are mature enough to survive outside of her body.  Surfactant, a lung protein, is essential for survival and breathing outside of the womb.  There is a protein within this lung surfactant that serves as a hormonal signal for labor and makes this signal once the surfactant has been properly developed.  It's a lot to think about when a doctor is asking you if you want to induce after 37 weeks.  While babies may be able to technically survive outside the woman at this point, their lungs have still not signaled full maturity.

So ladies, if you are starting to get fussy like I am, and baby hasn't arrived, just know that he needs the extra time getting his lungs ready.  And when baby is ready...it's eviction time!