Labor, Delivery, and Changes at Birth Fred Hill, MA, RRT
Feb 24, 2016
Labor, Delivery, and Changes at Birth
Fred Hill, MA, RRT
Fetus in Uterus
Fetus in Uterus
Events of Birth (Maternal)
Rupture of membranesDilation of cervixContraction of uterusSeparation of the placentaShrinking of the uterus
Stages of Labor & Delivery
Stage I: Onset of regular contractions to full dilation and effacement of the cervix Primigravida: 16 – 18 hours Multigravida: 7 – 12 hours
Stage II: Full dilation (10 cm) and effacement of the cervix to delivery of the baby Primigravida: 1 – 2 hours Multigravida: 20 mins
Stage III: Delivery of the baby to delivery of the placenta Primigravida: 3 – 4 mins Multigravida: 4 – 5 mins
Tocolysis
Beta-2 sympathomimeticsTerbutaline sulfateRitodrine hydrocholoride
Magnesium sulfateIndomethacinCalcium channel blockers
Dystocia
Uterine dysfunctionAbnormal fetal presentationCephalopelvic dysproportion
HydrocephalusExcessive fetal size (maternal diabetes)Small pelvic dimensions
Abnormality in shape of birth canal
Abnormal Fetal Presentation
Normal presentation: Vertex ( head first), 95%
Abnormal presentationCephalicBreech (buttocks down)FaceBrowShoulderTransverse lie
Vertex Presentation
Cephalic Presentation
Face Presentation
Complete Breech
Footling Breech
Frank Breech
Transverse Lie
Other Problems
Prolapse of umbilical cordCord wrapping around fetusPlacental abnormalities
Placenta previa: Implantation in lower uterus
Abruptio placentae
Placenta Previa
Abruptio Placentae
Other Risky Deliveries
Cesarean deliveriesMultiple gestations
Changes at Birth
Vaginal squeeze when head presentsPresentation of chest and recoil of chestFirst breath: high initial pressures (-100 cm
H2O)Succeeding breaths require less negative
pressureRemaining liquid in lungs
Expelled by coughing and sneezing Absorption into lung interstitium into lynphatics
Fetal Circulation
Fetal to Adult Circulation
Major changes First and subsequent breaths
Reduces pulmonary vascular resistanceAir replaces liquid surrounding vasculature↑ PaO2 → pulmonary vasodilation
Increase in systemic vascular resistance Clamping of umbilical cord
R → L Shunting changes to L → R Foramen ovale closes: mechanical Ductus arteriosus begins to close due to
chemical changes Cessation of blood flow leads to constriction of:
Ductus venosus Umbilical arteries and veins