Normal and Abnormal Labour

 

Normal labour: regular, frequent uterine contractions with cervical changes and descent of the presenting part

 

Stages of labour

I –        Latent: up to 3-4 cm dilation and effacement (false labour, pre-labour)

            Active: 4cm to full dilation → abnormal if <0.5cm/hr over >4hours

II –       Full dilation to delivery → abnormal if no descent over >1hour pushing

III –     Delivery of placenta

IV –     2 hours postpartum (may be up to 6 weeks)

 

Dystocia – arrest of progression of labour

Assess the the 5 P’s:

-         Power:

o       Strength of contractions (not on monitor, must feel)

o       Must have rest in between ( beware of tachysystole, coupling)

o       May be augmented with oxytocin

-         Passenger

o       Size

o       Lie: longitudinal/transverse

o       Presentation: face (mentum – anterior can deliver vaginally), brown (frontum), vertex (occiput), transverse (shoulder), breech (sacrum)

o       Position: OA 8.5cm diameter, OP 9cm, brow 13cm

o       Attitude: asynclitism

-         Passage

-         Psyche

-         Pain

o       Reduce stimuli (maternal movement, ARM for decompression)

o       Activate peripheral sensory receptors (water, TENS)

o       Enhance descending inhibitory pathway (hypnosis, music)

o       Narcotics (with antiemetic)

o       Entanox (inhaled N₂O)

o       Do not use sedatives/hypnotics

o       Epidural: most effective, does not lengthen 1^st stage

o       Pudendal: use in 2^nd stage (10cc local under ischial spines)

o       Perineal infiltration

 

Arrest of 1^st stage: amniotomy, oxytocin augmentation, therapeutic rest with analgesia (epidural), C-section

 

Oxytocin augmentation (drip because of short t_1/2 titrated to contractions)

-         Unsatisfactory in 1^st or 2^nd stage

-         Inadequate uterine contractions

-         After analgesia, rest, amniotomy

-         Prior to operative vaginal delivery to achieve adequate contractions

-         Beware of hyperstimulation