Student Nurse Laura

Orem – "creative effort of one human being to help another human being."

The Factors of Labor, Factor 1

Posted by Laura on March 11, 2010

1st Factor of labor:


               During the 2nd stage of labor its the baby, and the Placenta during the 3rd semester. 

Our passenger must fit between the symphysis pubis and the sacral prominence of the passageway as it moves down the station from a -5 to 0 (engagement) at the ischial spine to a +5 birth (SIZE OF FETAL HEAD.) If we can perform the Ballottement ( a technique for palpating a floating fetus by tapping the head away from the station to feel it then return to the examiner’s hand), then we know our passenger is in station.  This is where the Biparietal diameter comes into play.

  • biparietal diamerter – 9.25 cm anterior to posterior
  • suboccipitobregmatic diameter – 9.5 cm transverse

Our passenger has landmarks of presentation based on the FETAL PRESENTATION: 1. CEPHALIC (occiput) 2. BREECH (sacrum) 3. SHOULDER (scapula).

For most babies it is the cephalic or head first. The presenting part Mentom – fetal chin, Siniciput – anterior brow, Pregma – Anterior Fontenella, Vertex – between fontanelles, Posterior fontanelle and Occiput – Occipital bone.

FETAL LIE is normally with the long axis of the mom – longitudinal, vertical (transverse, horizontal), or oblique.

FETAL ATTITUE is hopefully the baby flexed .

FETAL POSITION is the presenting part that overlies the pelvic inlet and is stated in a 3 letter abbreviation. The 1st letter is the location of the presenting part (R) or (L). The middle letter is the presenting part of the fetus (O-occiput, S- scapula, M-mentum or chin, Sc- scapula). The 3rd letter is location of the presenting part in relation to the maternal pelvis (A-anterior, P – posterior, T-transverse).  Position is sometimes referred to the 6th Factor of Labor.

so test your knowledge – ROA is?   LSP     RMP      LScT

To me you would start with the middle letter first. What is coming down, the back of head, shoulder or chin? Lets say back of head = __ O __

Then is the back of head facing the mom’s right or left? =  RO___

3rdly (? sp) would you say the back of head is more to the posterior, anterior or transverse (right on the line)?   ROA

Can you say what the Lie, Presentation, Reference Point and Attittude might be?   


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