Mechanism and Management
-
Of Normal Labour
Labour is defined as the process by which the fetus, placenta, and membranes are
expelled from the uterus through the birth canal after 28 weeks of gestation.
Characteristics of Normal Labour:
•Spontaneous onset •At term (37–42 weeks)
•Vertex presentation •No undue prolongation
•Without maternal or fetal complications
•Minimal aid or intervention
•Complete expulsion of fetus and placenta
Stages of Labour:
-
Stage Definition Duration
Onset of true labor → Full cervical dilatation
12–14 hrs in primigravida, 6–8
1st
hrs in multi
(10 cm)
30–60 mins in primi, 15–30
2nd Full dilatation → Delivery of the baby
mins in multi
3rd Delivery of baby → Delivery of placenta Within 5–15 mins
Immediate postpartum period (monitoring
4th First 1 hour after delivery
maternal condition)
, Stage 1
fetus Uterus
Cervix
-
Vagina
Umbilical Effaced cervix
cord
Stage 2 Stage 3
Cervix
Umbilical clamp
Placenta Umbilical
cord Vagina
Crowning of the head
Mechanism of Labour:
1.Engagement
•The biparietal diameter (9.5 cm) enters the pelvic brim.
•Head enters the pelvis in occipito-transverse or oblique position.
2.Descent
•Continuous throughout labour; maximum in second stage due to maternal pushing.
3.Flexion
•Chin moves toward chest, allowing the smallest diameter (suboccipitobregmatic – 9.5
cm) to pass through.
4.Internal Rotation
•Occiput rotates anteriorly 45° (OT to OA) to lie behind the symphysis pubis.
-
Of Normal Labour
Labour is defined as the process by which the fetus, placenta, and membranes are
expelled from the uterus through the birth canal after 28 weeks of gestation.
Characteristics of Normal Labour:
•Spontaneous onset •At term (37–42 weeks)
•Vertex presentation •No undue prolongation
•Without maternal or fetal complications
•Minimal aid or intervention
•Complete expulsion of fetus and placenta
Stages of Labour:
-
Stage Definition Duration
Onset of true labor → Full cervical dilatation
12–14 hrs in primigravida, 6–8
1st
hrs in multi
(10 cm)
30–60 mins in primi, 15–30
2nd Full dilatation → Delivery of the baby
mins in multi
3rd Delivery of baby → Delivery of placenta Within 5–15 mins
Immediate postpartum period (monitoring
4th First 1 hour after delivery
maternal condition)
, Stage 1
fetus Uterus
Cervix
-
Vagina
Umbilical Effaced cervix
cord
Stage 2 Stage 3
Cervix
Umbilical clamp
Placenta Umbilical
cord Vagina
Crowning of the head
Mechanism of Labour:
1.Engagement
•The biparietal diameter (9.5 cm) enters the pelvic brim.
•Head enters the pelvis in occipito-transverse or oblique position.
2.Descent
•Continuous throughout labour; maximum in second stage due to maternal pushing.
3.Flexion
•Chin moves toward chest, allowing the smallest diameter (suboccipitobregmatic – 9.5
cm) to pass through.
4.Internal Rotation
•Occiput rotates anteriorly 45° (OT to OA) to lie behind the symphysis pubis.
