Contracted Pelvis. Fetal
Macrosomia
Lecture by Andriy Berbets
Measurement of the pelvis
Normal pelvis
Normal pelvis
Anatomically contracted pelvis
• The diagnosis is correct, if at least one
diameter is contracted 2cm +
• Classification:
- Generally contracted pelvis
- Simple flat pelvis
- Flat rachitic pelvis
- Transversely contracted pelvis
Anatomically contracted pelvis
Classification (by degree of contraction)
- 1st degree (conjugata vera 11-9 cm)
- 2nd degree (conjugata vera 9-7,5 cm)
- 3rd degree (conjugata vera 7,5-6,5 cm)
- 4th degree (conjugata vera less than 6,5 cm)
Generally contracted pelvis
Generally contracted pelvis
Generally contracted pelvis
• All the dimensions are equally contracted
(longitudinal and transverse)
• Delivery:
- over-flexion of the fetal head,
- passing of the fetal head through the pelvis on
oblique dimension,
- fetal head can’t fixate good enough to pubic
symphysis
Generally contracted pelvis
Generally contracted pelvis
Generally contracted pelvis
Generally contracted pelvis
Simple flat pelvis
Simple flat pelvis
•
•
•
•

All longitudinal dimensions are contracted
Internal rotation is problematic
Moderate extension of fetal head
Asynclitism
Asynclitism
Rachitic flat pelvis
Transversely contracted pelvis
Alternative classification
Alternative classification
Michaelis’ rhombus
Clinically contracted pelvis
•
•
•
-

Anatomical dimensions are normal
But fetus is too big and can’t pass through
Conditions for diagnosis:
Good regular uterine contractions
Cervical dilation 8cm +
Absence of amniotic sac
Empty urine bladder
Clinically contracted pelvis
•
-

Diagnosis:
No fetal head’s descending
Cervix is not closed to fetal head
High standing of contraction ring
Early pushing efforts (head is not in pelvic cavity)
Edema of cervix, vagina and vulva
Symptoms of urine bladder’s pressure
Positive signs of Vasten and Tsangemeister
Vasten’s sign
Threat of uterine rupture
Coxalgic pelvis
Ankilotic oblique-deformated pelvis
Pelvis due to osteomalatia
Scoliotic pelvis
Pelvis with no symphysis
Pelvis with no symphysis (“cleft”)
Osteoma
Shoulder dystocia
Shoulder dystocia
Thank you!

Contracted pelvis