Obstetrics Flashcards
What are some changes to the reproductive system during pregnancy?
- Uterine blood flow progressively increases from approximately 50/min at 10 weeks gestation to 450-750mls at term
- The spiral arteries increase in diameter
- Vascular resistance falls
- These changes accommodate the increased blood flow to the uterus under conditions of low blood pressure
* The uterus
* Increases in all dimensions and changes shape
* As the uterus expands it loses its anteverted, anteflexed configuration and becomes more erect, tilting and then rotating to the right under the pressure of the descending colon
* Pre-pregnancy weighs about 50gms and has 10ml capacity
* During pregnancy, weighs about 1100-1200gms and has a 5 litre capacity
What changes occur to the cardiovascular system during pregnancy?
- There are significant changes to the cardiovascular system
- Blood volume increases by 30-50% (1500mls)
- Blood flow increases to the uterus, breasts, other major organs
- Increased blood flow through uterus results in potential for major haemorrhage
- Formation of new blood vessels and vascular beds
- Peripheral vascular resistance is decreased
- Sodium and fluid retention (increased renal reabsorption)
- Results in increased circulation demands during CPR
What are some changes to cardiac output during pregnancy?
- Increases by 30-50%
- Heart rate increases by 15 bpm on average
- Stroke volume increases by about 10%
- Average increase of 1.5l/min from 4.5 to 6l/min
- In labour cardiac output increases by 2 l/min
- Output is affected by posture
- Compression of the inferior vena cava by the enlarging uterus during late second and third trimesters resulting in reduced venous return, Left lateral tilt is used whenever women are required to supine. E.g Cardiac arrest, unconscious pt, spine pt
How do you position a heavily pregnanct woman during transport/CPR
30 degrees to the L)
What are some haematological changes during pregnancy?
- Plasma volume increases more than red blood cell mass causing haemodilution- the marked increased in plasma volume causes dilution in circulating factors. Anaemia occurs.
- Pregnancy is a hypercoagulable state
- Bleeding time decreases by 30% because the ratio of clotting factors and fibrinolytic factors alter
- This hypercoagulability is optimal for placental separation and blood loss following birth
- However
- Women are more likely to develop clots during pregnancy
- Thromboembolism is a significant cause of maternal death
What are some physiological changes to the heart during pregnancy?
- Increases in size by approx 12%
- Increased contractibility
- Increased venous return thus increased atrium size
- Heart sounds change, the mitral valve closes marginally before the tricuspid
- Many women develop innocent systolic murmurs
- ECG changes: inverted T waves may be noted
- Later in pregnancy the heart is displaced upwards by elevation of the diaphragm and rotates forward so the apex beat is directed forward to the anterior chest wall
What are some respiratory changes during pregnancy?
- Diaphragm is displaced
- Circumference of the chest increases by about 15cm
- Increased flaring of lower ribs
- Pregnant women breath more deeply
- Oxygen consumption increases by 16-20% approx.
- Laryngeal oedema can make intubation more difficult
What are some GIT changes during pregnancy
- Increased appetite and thirst
- Develop cravings or aversions
- Sense of smell enhanced
- 50-90% of women will have some nausea/vomiting
- Heart burn common 30-70% as a result of intragastric pressure
- Gastric motility decreases
- Increases risk of aspiration
What questions would you ask when taking an obstetric history?
- Primigravida or multigravida?
- Gestation (< 37 weeks preterm)
- Past obstetric history?
- Any issues during this pregnancy?
- Multiple pregnancy?
- Any significant medical history?
- Any current medications?
- Significant social history & family circumstances?
- Contractions?
- Membranes?
- What colour is the fluid?
- Position of baby if known?
- Previous labours (were they quick labours)?
What is considered “full term”
37-42 weeks gestation
What is the first stage of labour?
Onset of painful regular, strong, rhythmic contractions resulting in dilation of the cervix to 10cm
Initial contractions are 10 minutes apart and 10–30 seconds in duration.
Contractions will increase to 4-5 in 10 minutes, lasting over 60 seconds.
May or may not have ruptured membranes.
Engagement occurs as the infant’s head enters the true pelvis.
What is second stage of labour?
Full dilation of cervix –> birth of the baby
What indicates imminent birth?
- Strong urge to push or defecate
- Stretching of the perineum
- Presenting part visible
- Spontaneous rupture of the membranes
- Fresh “show”
- The woman says ‘ baby is coming’
Can you suction a neonate and how?
- Only suction if you can see copious blood/secretions.
- Suction baby’s mouth then nose.
- Use a Fg 10 or Fg 12 suction catheter.
- The negative suction pressure used should not exceed 100 mmHg (13 kPa, 133 cmH2O, 1.9 Psi).
- Be quick (no more than 5 - 6 seconds) and gentle
- vigorous suctioning can cause laryngeal spasm, bradycardia, trauma and delay the onset of spontaneous breathing.
What care do you need to provide to the mother?
- Maternal vital signs 15/60
- tachycardia prior to PPH
- Feel abdomen
- ? another fetus.
- Maternal complications.
- Clean & check perineum for lacerations
- PPH
- Warm, dry & comfortable.
- Monitor fundus after placenta has birthed
- Check fundus but do not rub the fundus unless woman is bleeding and has no tone
- Monitor vaginal blood loss.
- Take any blood soaked linen with the mother.
Explain the APGAR score
Recite normal birth CPG (part 1)
Recite normal birth CPG (part 2)
Recite Breech CPG (Part 1)
Recite Breech CPG (Part 2)
Recite cord prolapse CPG
Recite shoulder dystocia CPG (part 1)
Recite Shoulder dystocia CPG part 2
