Third stage of labor and effect of labor on mother and fetus
Defintion: Defintion 3rd stage of labor: commences with the delivery of the fetus and ends with delivery of the placenta and its attached membranes.Duration:- normally 5 to15 minutes.- 30 minutes have been suggested if there is no evidence of significant bleeding.
Cause of placental separation After delivery of the fetus,the uterus retracts and theplacental bed diminished. As the placenta is inelasticand does not diminish insize it separates.
primary and secondarymechanism for placental separation
Primary mechanism is the reduction in surface area of placental site as the uterus shrinks
Secondary mechanism is the formation of haematoma due to venous occlusion and vascular rupture in the placental bed caused by uterine contractions
Schultze MethodPlacenta separates in the centre and folds in on itself as it descends into the lower part of uterus (80%).Fetal surface appears at vulvawith membranes trailing behindMinimal visible blood loss as retroplacental clot contained within membranes (inverted sac)
Duncan Method separation starts at thelower edge of placentalateral border separates (20%). maternal surface appears first at vulva Usually accompanied by more bleeding from placental site due to slower separation and no retro placental clot.
Signs of Separation and Descent lengthening of theumbilical cord outside. The uterus becomesfirm and globular (Descent). The uterus rises in theabdomen. A gush of blood(separation ).
Assess the uterus1-To exclude an undiagnosed twin2-To determine a baselinefundal height3-to detect the signs of placenta separation4- to detect an atonic uterus.
Control of Bleeding 1. Normal blood flow through placenta site is 500-800 ml/minute (10-15% of cardiac output) 2.Strong contraction/retraction of uterus constrict blood vessles by interlacing muscle fibres in myometrium (“living ligature”) 3. Pressure exerted on placental site by walls of contracted uterus 4. Blood clotting mechanism (sinuses and torn vessels)
Active vs physiologic managementActive management includes a prophylactic oxytocic drug,early clamping and cutting of cord and controlled cord tractionPhysiological management involves no prophylactic oxytocic drugs, no cord clamping until after placental delivery and no cord traction
Physiological ActivePlacental By gravity and By controlled corddelivery maternal effort traction with counter traction on fundsUterotonic after placenta delivery With birth of anterior ShoulderUterus Assessment of size Assessment of size and tone and toneCord Clamping Variable Early
Physiological Management Passive or expectant management No prophylacticoxytocics Cord clamped afterdelivery of placenta No Controlled Cord Traction (CCT)
Physiological Management Upright/kneeling/squatting position best- easy to observe blood loss Hands off just check uterus contracted and observe PV loss waits and watches for signs of separation and descent Mother expels placenta when she feels contraction and placenta in vagina
Active Management Reduceslength of 3rd stage and incidence of PPH (blood loss and need for transfusion)Oxytocic given after birth ofShoulder (check for a twin/no shoulder dystocia) Cord clamped and cut Placenta delivered by Controlled Cord Traction
Controlled Cord Traction CHECKS FIRST! Check that an oxytocic (uterotonic) has been given Why? Check that the uterus is well contracted Why? Check that countertraction is applied (Brandt- Andrews manoeuvre) Why? Check for signs of separation & descent Why? Check that cord traction is released before countertraction is stopped Why?
Which is better active or physiologic management ? Active management is superior to physiological in terms of blood loss Physiological management is only appropriate for women with low risk of PPH and who have normal physiological labour If physiological management is attempted but intervention is subsequently required ( the placenta is retained after one hour) active management should be considered.
After Care: Before leaving to check placenta and membranes Check the uterus is well contracted Check that PV loss is minimal Inspect perineum, vulva and vagina in good light (? Repair) Babyshould be pink (respirations; heart rate) warm, fed, cord clamp secure
check placenta and membranesfor completeness and normality
1 st stage: anxiety & mild tachycardia. 2 nd stage Pulse: up to 100 b.p.m. Temp: mild increase (37.5 - 37.7). B.P. systolic increased during pains.Conjunctiva; edematous & congested. Birth canal: minor lacerations in the cervix or perineum especially in PG.
3rd StageBlood loss from Placental site = 200-300 C.C due to placental separation. Lacerations or episiotomy = about 100 - 200 C.C
Moulding Overlap of the flat bonesof the vault of the skull due to compression ofthe head during labourleading to alteration inits shape
Types & Degrees a. Physiological: "beneficial“ decreases the size of head & facilitates its passage through the birth canal. 1. First degree: 2. Second degree
Pathological : may lead to intracranial hemorrhage3 rd degree:Overriding of one parietalbone over the other withContractions but it is notReducible inbetween. 4 th degree: overriding of the 2 parietal bones over each others & both override the occipital