EXSS2026 Lecture Notes - Lecture 2: Gestational Age, Pilates, Birth Weight
22 Aug 2018
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Department
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Professor
Physical Activity & Pregnancy: Lecture 2
Pre-Natal Development:
• Stages:
o Germinal: conception → 2 weeks (~3-4 weeks of pregnancy; period before
implantation)
o Embryonic: until ~week 10 of pregnancy (8 weeks from conception; cell
differentiation, gastrulation [ecto/meso/endoderm])
• Trimesters:
o 1st: weeks 1-13; cells form, tissue differentiation
o 2nd: weeks 14-26; growth of developing baby, hormonal changes causing growth
o 3rd: weeks 27-40; further growth of baby
Pre-Natal Changes:
• CVS:
o Increase CO by 40% (how much blood is pumped around body every minute)
o Increase SV (pumps quicker)
o Increase HR
o Increase blood volume by 40-50%
o Decrease systemic vascular resistance (flow more easily)
o Increase blood flow to uterus (baby requires blood for O2/nutrients)
• Cardiorespiratory:
o Increase tidal volume (breathe more)
o Increase VO2
o Impaired ventilation (diaphragm rises 4cm to create space for baby)
• Non-physiological:
o Shift in CoG (increase imbalance)
o Increase in joint laxity (flexibility)
o Increase risk of strains/sprains
• Metabolic:
o More protein in blood
o Increase fat around body
o Increase blood fats
o Increase salt (increases plasma volume in vessels)
o Increase water retention (due to above; causes swelling)
o Increase body weight (10-13kg)
• Hormonal (physiological):
o Increase lutenisisng hormone/growth hormone/placental lactogen/progesterone/
estrogen
• Psychological:
o Mood fluctuations
o Emotional liability and inestability (instability)
o Prenantal depression (10-30%)
