13. Labor Anatomy ->>

Test your knowledge and take the QUIZ at the bottom of the page! If you have questions, write them in the comment box.

14. Stages of Labor

When you understand what is happening to your body you can anticipate the physical sensations you may have.  How you respond and interpret the physical sensations  of labor are totally individual!  Not every woman experiences the same discomforts and  the level of discomfort will also vary.

So, look to your own experience as an individual one. AVOID COMPARING yourself to other women!

Sure, listen to what your friends have to say about their birth experiences, however it doesn’t mean what they experienced will happen to you.

Befriend your body!  A woman’s body is designed beautifully, chemically,  and engineered to work efficiently to birth your baby. Actually, your body wants to impress you with one of greatest jobs it will ever have – birthing your little one.

Find the following body  parts on the image below:  Bladder, Rectum, Cervix, Spine, Placenta, Vagina, Pubic bone,  Amniotic Fluid, etc.


Image from Pampers Advertisment


Fist , notice the spine in this picture. See the exaggerated curve? This is one of the reasons why so many women, perhaps even you, have low back aches. It’s because of the additional weight. Invest in a “Birthing Ball” (exercise ball) to relieve back aches.

What are the anatomical structures involved in birth?

  • The uterus is where the fetus  grows and develops during the nine months of pregnancy.  It uterus stretches in size as the fetus grows.  It is a muscle and when labor starts, it  contracts and relaxes  in waves to birth the baby ( Remember, because the uterus is a muscle, it responds to stress and will tighten).
  • The uterus has a “front door” or an opening to the space where the fetus is developing which is called the cervix. The baby will pass through the cervix and down the vagina, or more commonly called – the birth canal. Until labor begins, the cervix is closed, long and thick, and the mucous plug is in place. No cervical change (dilation) has happened.  You are in labor when dilation of the cervix begins.
  • The Placenta, is the “transfer station” where all the exchanges of oxygen nd waste products to and from the baby to mom happens! Nutrients are passed from mom to baby, wastes are removed  through the placenta. Immediately after birth the placenta shrinks to the size of a melon! This action helps the placenta to detach from the uterine wall and is usually delivered soon after the birth of baby – usually within 30 minutes!

When labor begins the cervix softens or “ripens” and begins to change its thickness, called “cervical thinning” or effacement. The size of its opening in diameter is called dilation. Effacement of the cervix is measured in percentages (100% being completely thinned, like tissue paper, and 0% being long and thick).  Dilation is measured in centimeters (10 centimeters is a completely dilated cervix and is equal to about 4 inches in diameter).

Contractions are necessary for effacement and dilation to occur. With each contraction the uterus works to pull up its muscle causing effacement and dilation to happen. At the same time contractions help baby to come down, or “descend” more into position for birth.  The pressure of the baby’s head against the cervix also stimulates effacement and dilation.

The Kegel exercises which tone and strengthen the muscles of the pelvic floor also help baby move down and in to position for birth.

Contractions need to be strong for birth to happen. As labor progresses contractions get stronger, longer, and closer together.  Women experience a range in physical sensations.  Contractions may feel very mild like a “menstrual cramp”, like “gas”, or uncomfortable – to be determined by mom-to-be  :-). Some women in early, and in early active labor, don’t feel any discomfort at all.   Again, this is totally individual, and unique only to you.

Speaking of contractions, what are those Braxton-Hicks everybody talks about? Yes, your uterus is gearing-up for the job of birthing your baby with “practice” contractions.  They are:

  • usually mild tightening sensations of your belly!
  • Your belly tightens hard as a “drum” then subsides and goes away
  • They are irregular, mild, do not cause cervical changes
  • Go away with a change of activity, or movement
  • They can be stimulated by dehydration
  • short in duration
  • Drink lots of fluids daily such as water, juice, and NO coffee, soda, etc.

Also, should Braxton-Hicks, or any contractions happen to you before 36 weeks of pregnancy, occur4 or more times in an hour, call your doctor or midwife. You could be experiencing pre-term labor, and your doctor will need to see you to determine this or not.

 Real labor or “true” contractions do not go away, they cause cervical changes, are regular, and get stronger, longer, and closer together as labor progresses.

The bladder sits in front of the uterus, and just above the pubic bone.  During pregnancy, especially during the first and third trimesters, you’ll experience the urge to go to the bathroom frequently.  Why?  Well, the bladder can hold up to about 1000 cc, or one liter,  of fluid. With a growing, developing baby in the uterus the bladder will not have the space to hold such an amount of urine because the uterus is taking up a lot of space!  As a result, you will feel the urge to empty your bladder many times during the day, in the evening, even during the night.

Now, what may seem to be bothersome to you, running back and forth to the bathroom, it  is actually a good thing!   You want to empty that bladder!  First of all, it can be quite uncomfortable to be pregnant with a full bladder.  Also during labor a full bladder can block the passage way of the baby’s birth (review where it is in the image above).  Simply emptying your bladder hourly can prevent this.

Your rectum is behind the uterus. In late labor just before delivery of the baby, you may feel like you have to have a bowel movement.  This is because as baby descends down the birth canal you may feel a lot of rectal pressure from the baby’s head putting pressure on the rectum.  This is often referred to as the “urge to push”. You may also experience hemorrhoids ( swelling of small blood vessels) from the pressure and from pushing.

When we talk about the Stages of Labor, you’ll learn more about pushing and how the physiology comes together to birth your baby. You and your baby are a team! More to come …

Birth bold,

Lesly 🙂

Now, test your knowledge! Take the QUIZ! Got questions? Write them in the comment box below.


1. What are Braxton-Hicks?

2. What does Effacement mean?

3. What is Dilation?

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