Normal Labor and Delivery

Valerie Robinson D.O.

Definition of Labor

• Contractions• Become regular• Increase in strength and frequency

• Cervical change: Dilation and Effacement• Normal is >1.2cm/hour in P0, >1.5cm/hour in P>0• 0% effacement is 3-4cm thick

• ROM may be spontaneous or assisted• 3 factors affecting successful labor and delivery are the

Power, Passenger, and Passage

3 Stages

• #1: Onset to full Dilation• #2: full Dilation to Delivery• Mom wants to bear down• May feel rectal pressure• May have N/V

• #3: Delivery to Placental expulsion

4 Phases

• Latent – Onset of labor and slow cervical dilation• Active – Rapid cervical dilation. Usu begins at 2-4 cm• After• Involution – Empty uterus contracts to become smaller

and hard. Stops bleeding.

Power

• Tocodynamometer (TOCO) measures length and strength of contractions

• May also use IUPC after ROM• Adequate contractions for labor are 3-5 per 10 minutes

Passenger

• Size• Presentation: breech, vertex, transverse• Position: LOA, etc• Movements• FHR• How many babies are there?

7 cardinal movements

• Engagement – widest diameter is below pelvic inlet• Descent• Flexion• Internal Rotation – rotation into the AP dimension• Extension – occiput contacts the pubic symphysis• External Rotation – head rotates to correct anatomy• Expulsion

Fetal heart monitor

• Baseline – average FHR over 10 minutes. 110-160• Variability – Fluctuations in FHR amplitude• Absent• Minimal - <5 BPM• Moderate - 6-25 BPM• Marked - >25 BPM

• Accelerations – increase from baseline• Normal is a 15 BPM increase lasting at least 15 seconds, <2 minutes• If it lasts >10 minutes, it is a baseline change

• Decelerations – decrease in FHR with return to baseline• Early• Late• Variable• Prolonged - >2 minutes

Passage

• Is the pelvic outlet large enough?• Infections such as GBS, herpes, hepatitis

Initial Assessment

• Check cervical D/E/S• Dilation: 0-10 cm• Effacement: 0-100%• Station: – 5-+5cm above-below ischial spines

• Check presentation and position• Check for ROM; color and quantity• Check vitals• Apply TOCO and Doppler transducer• Review prenatal chart

L&D Care

• IV fluids are not necessary• IV access should be gained for emergency, labor

augmentation, antibiotics• Restriction of drink is not necessary, but food may be

restricted due to risk of aspiration pneumonitis• Pain control• Encouragement and reassurance• An anterior cervical lip lasting >30 minutes may be

normal or may indicate a malposition

Delivery

• Nurse or doctor will check labor progression by monitoring TOCO and checking Dilation/Effacement/ Station

• Allowing passive descent instead of pushing at 10cm increased chance of SVD, decreased chance of instrument assistance, decreased pushing time

• Pushing: Reflexive, or Valsalva. 10x3 in contraction• May use hands to support the perineum or fetal head and

reduce risk of tearing.• May do a manual reduction of an anterior cervical lip• Episiotomy is only used when there is a risk of severe

perineal laceration• Watch for and reduce a nuchal cord

Delivery cont.

• Deliver anterior shoulder, use downward traction on the head in concert with contractions

• Then upward traction to deliver posterior shoulder• Suctioning may be performed but has not been shown to

have any benefit except in babies with obvious secretory obstruction or who will be on a ventilator

• Cord clamping can take place immediately, but there is some benefit to delaying it so the placenta can deliver more blood to the baby. 75% of available blood is transfused in the first minute following delivery.

• Cord blood can be collected for diagnostic purposes• Cord blood pH is measured by needle aspiration of artery

Stage 3

• Uterus contracts, placenta separates, cord lengthens• WHO suggests that placenta is retained after 1 hour• Retained placenta increases risk of hemorrhage• More commonly retained in preterm delivery• Active management includes: Prophylactic oxytocin, Cord

traction, and Uterine massage• When providing cord traction, support the fundus to prevent

inversion

• Slowly rotate the placenta as it is delivered, so you can get the attached membranes out intact.

Repair lacerations

Post-Partum

• Check incision if C/S• Birth control• Screen for depression• Breast-feeding?

References

• Costanzo, Linda S. Physiology. 3rd Ed. Saunders/Elsevier: Philadelphia, PA. 2007. pp. 456-460

• Gordon, John David MD, Et al. Obstetrics, Gynecology, and Infertility: Handbook for Clinicians. 6th Ed. Scrub Hill Press: Arlington, VA. 2007. pp 87-88.

• http://www.gynaeonline.com/perineal_tear.htm• Funai Et al. Management of normal labor and delivery.

UpToDate. Updated 5/18/12.• Funai Et al. Mechanism of normal labor and delivery.

UpToDate. Updated 10/19/11.