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!