Physiology of pregnancy Flashcards
How long is pregnancy approx
270 days from conception to birth
Changes in physiology in pregnancy
Increase in basal metabolic rate by 15% Cardiac output increases by 30-40% as the heart works harder Blood volume increases O2 utilisation increases Ventilation increases
Average weight put on during pregnancy
24 lbs, foetus contributes to 7 lbs
Main hormones in pregnancy
Oestrogen, progesterone and hCG
What week does hCG peak
Weeks 7-12
Function of hCG
Supports the function of the corpus luteum until the placenta takes over
Function of oestrogen
Helps to maintain the uterus and its lining
Function of progesterone
Thickens uterine lining (endometrium)
Inhibits FSH and LH
Function of FSH
Stimulates follicular growth in ovaries
Stimulates oestrogen secretion
Function of LH
Surge causes ovulation
Results in the formation of a corpus luteum
Function of relaxin
Helps prepare the mother’s body for childbirth
What occurs during the first trimester
Morning sickness - peaks during the first trimester, positive correlation with birth weight Sensitivie/ sore breasts Frequent urination Constipation Fluctuating emotions
What occurs during the second trimester
Nausea and continuous vomiting Frequent urination Insomnia Indigestion and muscle cramping Leukorrhea - vaginal discharge - increased secretion from the vagina/ cervix
What occurs during the third trimester
10% of patients experience mild to moderate depression
Breathlessnes - pressure on diaphragm
Oedema of the ankles, toes - pressure on vena cava
Pre - eclampsia
Eclampsia
What changes occur in the digestive and urinary systems
Nausea, vomiting and constipation
Gastric reflux and heartburn
Downward pressure of the uterus on urinary bladder
What changes occur in the cardiovascular system
Increased blood volume
May hammer venous return
What changes occur in the respiratory system
Increased demand for oxygen
Increased maternal metabolic rate
Respiratory mucosa may swell in response to the increased blood flow during pregnancy
What changes occur to the skin
Skin stretching
Increased (melanocyte stimulating hormone produced by the pituitary gland)
Melasma, the ‘mask of pregnancy’
What is secretory differentiation in lactation
The tissues getting ready
What is secretory activation in lactation
The tissue delivering
What is the suckling reflex
Neuro- endocrine reflex
Positive feedback
When an infant is suckling, a neural message is sent to the hypothalamus
Prolactin is released from the anterior pituitary for milk production
Oxytocin is released from the posterior pituitary for milk secretion
Suckling at breast increases prolactin levels so at each feeding, levels risk hence more milk production
Effects of drugs if prescribed during the first trimester
Can cause congenital malformations (teratogenesis)
What is the period of greatest risk in pregnancy
3rd to 11th week
What LA can you not give during pregnancy
Felypressin/ Octapressin as it has oxytocin which induces labour
