Cephalopelvic Disproportion - (CPD)
This is a disparity between the fetal head and the maternal pelvis. It means that the particular head is too big for the particular pelvis through which it must pass, it may be due to:-
· A contracted pelvis with a normal sized head.
· A normal pelvis with a large baby ,or
· A combination of a large baby and a contracted pelvis
Cephalopelvic disproportion cannot be diagnosed before the 36th week of pregnancy because before then the fetal head is too small for comparison with the pelvis but at 36th week the fetus would have reached its maximum size.
There are three degrees of disproportion
· Minor degree: Here, the head does not engage or pass through the pelvic brim but it maybe possible to push it through the brim. The head is at the same level with the anterior boarder of the symphysis pubis. With good uterine contractions the head may be able to push through the brim.
· Moderate degree: - Here, the head cannot be made to engage at the pelvic brim, the head slightly overlaps the anterior edge of the symphysis pubis.
· Major degree:- Here, the head greatly overlaps the anterior edge of the symphysis pubis
1. Disproportion should be suspected in short primigravidae.
2. It is uncommon in multigravidae women with a previous history of spontaneous vaginal delivery of babies weighing more than 3.4kg.
3. A pendulous abdomen should lead to the suspicion of disproportion.
4. If at 38th weeks of pregnancy, the head cannot be made to engage
5. Non engagement of the head in a primigravida at 36wks in Caucasian is regarded as an ominous sign of cephalopelvic disproportion but in African, the fetal head does not engage until the 40th week or even towards the end of the first stage of labor, the head can however be made to engage by the head fitting test.
6. Diagnosis can be made by assessing:
· the degree of overlap of the head over the pelvic brim at the symphysis pubis
· Internal pelvic and external pelvic.
· X-ray Pelvimetry which is done at 38 weeks of pregnancy.
Major & moderate degrees of disproportion are delivered by elective caesarean section; patients with minor degrees of cephalopelvic disproportion are allowed trial of labour with the aim of achieving vaginal delivery.
Trial of labour: A test carried out in the presence of minor degreeof cephalopelvic disproportion to see if vaginal delivery will be possible. It is done in an equipped and staffed hospital for operative procedures in case vaginal delivery fails. The success of trial of labor depends on:
1. The effectiveness of uterine contraction
2. The flexibility or “give” of the pelvic joints
3. Flexion of the fetal Head.
4. The degree of moulding of the fetal head.
Ambulation and upright positions can be adopted to promote effective uterine contraction cervical dilatation and flexion of the head, progress of labour is recorded on a partograme, continuous fetal monitoring is used to assess fetal well being.
The aim of trial labor is to ensure a successful outcome of labour, if dilatation is slow and the head fails to descend, despite good uterine contractions, the decision must be made whether or not to allow labour to continue. If at any stage during this labour the mother or the fetus is under stress a caesarean section will be performed.
· Prolonged obstructed labour
· Vesico vaginal Fistula and Recto vaginal fistula.
· Rupture of uterus due to thinning of the lower uterine segment.
· Birth asphyxia
· Brain damage due to severe Birth asphyxia
· Ascending infection if ruptured membranes occurs for a long period
· Hypostatic pneumonia and respiratory distress.
· Venous thrombosis.