Week 1 - Lecture PDF

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Week 1 Lecture for CSB339...

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Week 1: Overview • Skin pigmentation - change • Body shape • Altered gait and posture - which can cause balance issues and falls Uterine Changes • 12/40 Uterus becomes abdominal organ - fungus palpable above pubic symphyxis. • Umbilicus 20 weeks • Xiphisternim 36 weeks Most significant changes occur to the cardiovascular system. Hypervolaemia • Total blood volume ↑ 30-50% for singleton pregnancies • >50% in multiples • Noted as early as 6th week, most takes place before 32-34 weeks Gestation. • Plasma volume ↑ up to 50% • RBC’s ↑18%. Physiological Anaemia - more severe consequences if a bleed occurs. • Hypervolaemia, • haemodilution • Hb ↓ White Blood Cells: • Neutrophils ↑ ◦ Peak is reached at 30 weeks • Eosinophils ◦ ↑During pregnancy ◦ ↓ During labour • Basophils and monocytes remain unchanged • Lymphotyces, B Cells and T Cell levels do not drop • Depression of cell-mediated immunity. ◦ Essential for survival of the foetus ◦ More susceptible to viral infections – MMR, poliomyelitis & Influenza ◦ Malaria leads to infected placenta and ↑ foetal mortality Physiological changes: Heart • Pushed upwards • Often Systolic or diastolic murmurs • ↑Cardiac Out put – Significant! • ↑HR – 15bpm • ↑Stroke volume • ↓BP • Uterine Perfusion

• 500 ml/min at term • Kidneys • Increases by 400ml/min • Skin Causes • Hormonal • Progesterone, oestrogen and prostaglandins • Mechanical • Growth and development of organs necessitating increased blood supply. Supine hypotensive syndrome • Gravid uterus on IVC • Impedes venous return • Tilt left, or right. As long as it is not flat on the back. • Becomes a concern about 20 weeks. • Baby can manually shifted off the spine Respiratory system Physical Changes • Airway changes • Altered shape of thorax • Diaphragm displaced by term by gravid uterus • Diaphragmatic to thoracic breathing Volume Changes • Tidal volume increases during pregnancy by 40% • Expiratory reserve volume decreases by 200ml • Alveolar Respiration (oxygen transfer) increases by 40% during pregnancy • Increased Oxygen demand Respiratory rate is usually stable ◦ Overbreathing ◦ Dyspnoea ◦ Discomforts Week 30 and above, pregnant women will note difficulty breathing Hormonal Changes • Relaxin ◦ Growth hormone ◦ Increases ligament and tendon laxity ◦ Prepares for birth • Oestrogen ◦ Fertilisation and maintaining pregnancy ◦ Growth stimulators • Progesterone ◦ Relaxes smooth muscle ◦ Vasodilatation - Haemodynamics ◦ Reduced gut motility.

• Oxytocin ◦ Essential for labour ◦ Essential for third stage ◦ Essential for Breast-feeding • Prolactin ◦ Breast milk production Gastrointestinal Changes • Oesophagus • Reflux/Oesophagitis 2/3 all pregnant women. • Increased appetite • Cravings, Aversions & Pica. • Stomach • Reduced gastric emptying • Constipation is common • May affect the absorption of oral medications • INCREASED RISK OF ACID ASPIRATION • Large Intestine • Gums become swollen & bleed easily • Increased appetite

Stages of labour First stage of Labour Latent Phase • Prior to active first stage • May last 6-8hrs to 1-2 days in primiparas • Contractions may vary – 1-2:10 min, mild, 20-40 seconds in duration • Mothers Cervix Effaces from 3cm long to 0.5 cm long (Usually soft and stretchy) • Cervix dilates from 0-4 cm dilated Active Phase • Cervix undergoes more rapid dilatation • Begins when cervix is 3-4 cm and is complete when cervix is fully dilated. • Recognised by 3-4:10, moderate- strong contractions 50-70 seconds in duration. • Usually lasts 1-2hrs/cm in primiparas • Usually lasts 1hr/0.5-1cm in Multiparas

Transitional Phase • The transitional phase is the stage of labour when the cervix is from 8-9cm to fully (or until expulsive contractions are felt by the woman. • Often a brief lull in contractions • Contractions can seem to ‘change’ to be less intense, with a longer break in- between. • Mood changes are common Second Stage of Labour From full dilatation of the cervix until the expulsion of the foetus . • Characterised by overwhelming urge to push • Contractions often have longer breaks in- between (3:10) • Can take up to 2 hours in a primipara • Can take up to 1 hour in a multipara (usually takes...