Confused in IA!!

enfermeraSG · Nov 17, 2006

OK, let's see if I can be of any help. Presentation is the easiest, it simply means which part of the baby is entering into the mother's pelvis/birth canal first. For example, "breech" presentation means the baby's rear-end is entering the birth canal first. Occiput/vertex presentation - then the head is entering first :w00t: Position is designated by 3 letters. The first refers to whether or not the presenting part is in the right or left portion of mom's pelvis. The second letter is technically the relationship of the baby's presenting part to the mother's pelvis (anterior, posterior, or transverse), but I have an easier time picturing mom & baby's back. For example, if the baby is "OP" (occiput posterior), then the baby's occiput (back) is closest to the posterior aspect of mom's body (aka: mom's back). If the baby is "OA", then the baby's back is closer to the anterior aspect of mom's body. Of course this would be opposite if the mentum is being used as the reference point. BTW, I have never in 9 yrs at a high volume facility heard anyone use that. I'm sure someone does though. If the baby is "OT", then the baby has it's side facing mom's spine.

Anyway, put it all together. If a baby is "ROA", the presenting part is the occiput; if you divided mom in halves of right and left :rotfl:, the occiput is in the right side of the pelvis, and the baby's occiput (or back) is closest to mom's anterior.

Sorry this was so long, but I hope it helped somewhat and not confused you more! Feel free to ask me any questions, SG

booknut · Nov 17, 2006

Thank you!! It SEEMS easy enough to remember, until I see pictures and I have to label them--I go BLANK!(you would think with 4 kids, it would be a breeze!!)

Saw my first birth (never had the desire to watch my own??) It was AMAZING!! Made me want to be pregnant again (am I sick or what??!! LOL) The whole birth process from beginning to end is incredible!

Have to go to work, I will read, and re-read your email until I get it! Thanks again!!

NurseNora, BSN, RN · Nov 19, 2006

Lie is about the relationship of the long axis of the baby as compared to the long axis of the mother. Ninety some percent of the time the lie is longitudinal, that is the baby's spine is parallel to the mother's--cephalic or breech are longitudinal lies. In a transverse lie, the baby's spine is at right angles to the mother's; in other words, the baby is crosswise in mom's uterus. Although during the pregnancy a baby may be in this position during a check up, they almost always move to a longitudinal position before labor starts. A baby in a transverse lie cannot deliver lady partslly.

Attitude has to do with how flexed the baby is. Usually in a cephalic presentation, the baby's head is flexed foreward onto her chest and the spine is flexed into a C curve. This position works best. Sometimes the baby has his head straight up, like a soldier at attention. This is called a Military Attitude and presents bigger diameters of the baby's head to the pelvis. Often, during labor, the baby's head does flex foreward and progress speeds up. Showing even less flexion, sometimes the baby looks up and the brow presents first, this is even less desirable than a military attitude. Tipping the head even farther back, some babies come face first. On X-ray, the spine looks like a letter S instead of a C. Surprizingly, a face presentation is more likely to deliver than a brow presentation.

Presentation has to do with what part of the baby is closest to the cervix. A cephalic presentation is head first, a breech presentation is butt first, both longitudinal lies. A shoulder or hip presentation would be transverse lies.

Presenting part is presentation in more detail. A cephalic presentation can be vertex (head flexed foreward, occiput at the cervix), brow, or face. A breech presentation can be a frank breech, baby flexed at the hips with just the buttocks presenting, or complete breech, baby tailor-sitting with legs flexed at the hips, knees bent, or a footling breech with one or both feet coming to the cervix first.

Position has to do with the relationship of a marker on the baby to the maternal pelvis. The pelvis is divided side to side into anterior and posterior and front to back into left and right (mother's left or right, not the examiner's). In a vertex presentation, occipital bone is the marker.If the baby is Occiput Anterior (OA) the occiput is in the front right part of the mother's pelvis, so it is facing her back. If the occiput is in the back (OP), the baby is facing the mother's front. The baby usually doesn't come down straight OP or OA, but is turned slightly to one side or the other, giving you ROA, LOA, ROP, and LOP. If the head is facing mother's hip, it is Right Occiput Transverse ROT, or LOT.

The marker for a face presentation is the chin or Mentum. So you have RMA, LMA, MA, RMP, LMP, MP, RMT,LMT. A baby in one of the Mentum Anterior positions can deliver lady partslly, but not if it's in one of the MP positions. (Picture a vertex delivery, as the occiput rotates under the symphis pubis you get extention of the head--it up from being flexed onto the chest. Now picture a baby coming face first, mentum anterior. The head is bent back as far as possible, looking out the lady parts. As the chin rotates under the symphisis the head comes foreward. If the chin is posterior, the head is bent back as far as it will go and it cannot rotate under the symphis because it cannot bend anymore. Try being the baby and go thru the motions yourself to get a feel for the different movements. Lie on your back with your head bent as far back as it will go and imagine you're rotating under the symphis, then lie on your stomach in the same position and you'll see why you just can't rotate under it.)

Breech presentations use the sacrum as the marker. SA,RSA, LSA, etc.

Sorry this is so long, I hope I haven't confused you even more. Just look at the diagrams and imagaine yourself in the different positions. There is a book Human Labor and Birth by Oxhorn and Foote that has very good diagrams of all the positions, presentations, lies, etc. Your school library probably has a copy of it. Good luck.

May_baby · Nov 19, 2006

Awesome replies!

booknut · Nov 20, 2006

wow! I appreciate all the time it took for you to explain this to me!! I can tell this site is going to be such a HUGE blessing to me!! What a great group of nurses! Thank you all again for the help!! Test is on Tues, and I hope I do well in it!!

Dixielee, BSN, RN · Nov 20, 2006

:chair: When you have been a nurse for 20 or so years, and you are running around working in a busy ER, the only OB position you will be concerned about is HOW FAST CAN I GET THIS WOMAN IN A WHEELCHAIR AND UP TO L&D???:rotfl:

I sure am glad I am not back in school! Good luck.

SmilingBluEyes · Nov 21, 2006

excellent posts here. Thank you for your help, guys.