Physiological Adaptation To Pregnancy Flashcards
ENDOCRINE SYSTEM
What early pregnancy changes occur to the endocrine system due to trophoblastic cells?
Trophoblastic cells start to secrete HCG
ENDOCRINE SYSTEM
What is the purpose of hCG?
It maintains the corpus luteum
ENDOCRINE SYSTEM
What produces progesterone? What does progesterone do?
The corpus luteum secreted progesterone which nourishes the blastocyst and regulate the uterus (endometrium)
ENDOCRINE SYSTEM
When does the placenta take over progesterone production and why?
The placenta takes over progesterone production at 8-12 weeks because the corpus luteum degenerates
ENDOCRINE SYSTEM
Why would a pregnancy test show positive?
hCG hormone produced by syncytiotrophoblast diffuses into blood stream via villi into lacunae and is excreted into urine 2 weeks after fertilisation
ENDOCRINE SYSTEM
What are some symptoms caused by hCG?
Nausea/vomiting
Increased appetite and fat composition
Increased thirst and release of ADH
Increased sensitivity to glucose
ENDOCRINE SYSTEM
What does hCG do which prevents body rejection of the placenta?
It suppressed maternal lymphocyte response
ENDOCRINE SYSTEM
Bodily changes caused by progesterone
Relaxation of smooth muscle
Increased body temperature
Increased respiration
Increased sodium and chloride excretion
ENDOCRINE SYSTEM
Fetoplacental unit
A functional compartment responsible for synthesising hormones which maintain a pregnancy
ENDOCRINE SYSTEM
The production and secretion of hormones by the placenta requires the use of what?
Enzymes in the maternal and fetal circulation
ENDOCRINE SYSTEM
What is the relationship between the level of hCG to the level of hPL?
As hCG level falls, hPL rises
ENDOCRINE SYSTEM
What functions does hPL have?
It stimulates growth of fetal and maternal tissues
It protects the fetus from rejection
It has a diabetogenic effect (reduces glucose uptake from maternal cells so more is available for fetal use)
ENDOCRINE SYSTEM
Relaxin is produced by what
Corpus luteum and then the placenta when corpus luteum degenerates
ENDOCRINE SYSTEM
Relaxin function
Softens elastic ligaments which allows growth of uterus into abdomen
Maintains uterine quiescence by suppressing oxytocin release which affects gap junction permeability
ENDOCRINE SYsTEM
What hormone allows growth of the uterus and how?
Relaxin allows his by softening elastic ligaments
ENDOCRINE SYSTEM
What may be a cause of lower back pain in pregnancy?
Stretching of ligaments for the growth of the uterus. This is due to relaxin hormone softening elastic ligaments
ENDOCRINE SYSTEM
What hormone maintains uterine quiescence and how?
Relaxin suppresses oxytocin release by affecting the gap junction permeability. This prevents the uterus from contracting
ENDOCRINE SYSTEM
Which adrenal and pituitary hormones increase in pregnancy?
Cortisol
Prolactin
Melanocyte
ENDOCRINE SYSTEM
What may an increase in melanocyte hormone cause in pregnancy? (In severe cases)
Hyperpigmentation - tanning more deeply or chloasma (skin discolouration)
ENDOCRINE SYSTEM
What thyroid hormones increase during pregnancy?
T3
T4
Together these hormones regulate body’s temperature, metabolism and heart rate
ENDOCRINE SYSTEM
What does an increase in T3 and T4 in pregnancy cause?
A mimic of hyperthyroidism- increased temp, increased appetite, fatigue and increased metabolic rate
ENDOCRINE SYSTEM
What is an unpleasant side effect of the increased level of T4 in pregnancy?
Nausea and vomiting
REPRODUCTIVE STSTEM
Changes to the uterus in pregnancy
Blood supply increases Remodelling of spiral arteries causes decrease in blood resistance Lower blood pressure Uterine hyperplasia Uterine hypertrophy Defining of the 3 myometrium layers
REPRODUCTIVE SYSTEM
What changes occur as a result of the remodelling of spiral arteries?
Lower arterial resistance
Increased blood flow
Lower blood pressure
Increased blood supply
REPRODUCTIVE SYSTEM
Term for the development of new fibres- driven by oestrogen
Uterine hyperplasia
REPRODUCTIVE SYSTEM
Term for the Increase in length and thickness of fibres (driven by oestrogen)
Hypertrophy
REPRODUCTIVE SYSTEM
Uterine Isthmus
Inferior-posterior part of the uterus (cervical end)
REPRODUCTIVE SYSTEM
How does the uterine isthmus grow in pregnancy?
A non pregnant isthmus is 7mm. In early pregnancy is increases to 25mm. Between 32-34 weeks the isthmus forms to lower uterine segment
REPRODUCTIVE SYSTEM
What hormones maintain uterine quiescence?
Progesterone
Relaxin (suppresses oxytocin)
Nitric oxide
Prostaglandin
REPRODUCTIVE SYSTEM
What are Braxton hicks contractions?
Painless contractions which do not dilate the cervix. They assist in circulation of blood to the placenta.
They are irregular, weak and unsynchronised
REPRODUCTIVE SYSTEM
What changes to the cervix during pregnancy?
Increased blood supply (caused by oestrogen) softens the cervix
Collagen fibres become less tightly bound and water content increases
Cervical mucosa proliferates and secretes mucus to protect from infection
REPRODUCTIVE SYSTEM
Vaginal changes in pregnancy
Increased blood flow (osianders signs)
lilac colour of vagina and cervix (jacquemiers sign)
Increased discharge
Oestrogen causes hypertrophy of muscle layer- increased capacity and elasticity
CARDIOVASCULAR SYSTEM
Changes to cardiac output in pregnancy
Cardiac output increases due to increased heart rate
Blood volume also increases
Oestrogen causes hypertrophy of cardiac muscle
CARDIOVASCULAR SYSTEM
Changes to blood pressure in pregnancy
Systolic pressure has very little jangle in pregnancy
Diastolic pressure is lower in the first trimester due to decreased resistance to flow
Postural hypertension
CARDIOVASCULAR SYSTEM
Symptoms of high blood pressure changes in pregnancy
Oedema of lower extremities
Diuresis
Varicose veins of legs and vulva
Haemorrhoids
CARDIOVASCULAR SYSTEM
What causes oedema in pregnancy?
Blood pressure
CARDIOVASCULAR SYSTEM
Diuresis
Excess production of urine, can be as a result of raised blood pressure
CARDIOVASCULAR SYSTEM
Oedema
Fluid retention in extremities due to progesterone which affects tone of blood vessels- increasing likelihood of leaking fluid and gravid uterus impeding flow
CARDIOVASCULAR SYSTEM
What can cause varicose veins and haemorrhoids in pregnancy?
Gravid uterus puts pressure on blood vessels causing dilation of vessels.
Progesterone relaxes the walls of veins so that they relax more which can allow them to swell
CARDIOVASCULAR SYSTEM
Why should you avoid lying on your back in pregnancy?
Gravid uterus can compress on aorta and inferior vena cava causing reduced output and drop in blood pressure
CARDIOVASCULAR SYSTEM
How does oestrogen affect blood flow?
It increases blood flow to all tissues
CARDIOVASCULAR SYSTEM
How does progesterone affect blood flow?
It decreases venous tone, decreasing blood pressure
CARDIOVASCULAR SYSTEM
Why does blood flow to breasts increase in early pregnancy?
To help milk production
CARDIOVASCULAR SYSTEM
Why does blood flow to skin increase in pregnancy?
To expedite heat loss
CARDIOVASCULAR SYSTEM
What haematological changes occur in pregnancy?
Plasma volume increases by 40-50%
Red blood cell mass increases
Haemodilution- less blood cells in proportion to blood volume
Increase in fibrinogen and other clotting factors
CARDIOVASCULAR SYSTEM
Name one benefit and one risk to having an increase in fibrinogen and other clotting factors in pregnancy?
Benefit- protection against placental separation and sudden blood loss
Risk-thromboembolism (blood clot)
CARDIOVASCULAR SYSTEM
How is iron count affected in pregnancy?
It decreases- especially at 16-22 weeks. It is advised not to let it go below 110 in second and third trimester
RESPIRATORY SYSTEM
Changes to respiratory system in pregnancy
Increased oxygen consumption
Diaphragm displaces upwards
Increased flaring of the lower ribs increased chest circumference
RESPIRATORY SYSTEM
Why is progesterone a respiratory stimulant?
Progesterone lowers the sensitivity of chemoreceptors for carbon dioxide
RESPIRATORY SYSTEM
How is the tidal volume affected in pregnancy?
It increases as pregnant women breathe more deeply
RESPIRATORY SYSTEM
What can cause persistent cough/deeper voice in pregnancy
Oedema of vocal cords
RESPIRATORY SYSTEM
What can lead to respiratory infections in pregnancy?
Capillaries in respiratory tract become engorged
RENAL SYSTEM
Changes to passing of urine in pregnancy
Increased frequency
Leakage
Nocturia
UTIs
RENAL SYSTEM
Why does urine frequency increase during pregnancy?
Kidneys have more waste to excrete due to increased metabolism
RENAL SYSTEM
Nocturia
Waking up during the night to wee
RENAL SYSTEM
Kidney changes in pregnancy
Enlarges by 1cm length and 30% volume
Increased blood flow (haemodilution)
Increased glomerular filtration rate
RENAL SYSTEM
What changes to the blood and filtrate occur due to increased glomerular filtration rate?
More sodium, glucose and amino acids in filtrate however sodium is reabsorbed by tubular reabsorption
Lower levels serum creatine and urea
RENAL SYSTEM
What two urine conditions are common in pregnancy?
Glucosuria-doesn’t always indicate GDM
Proteinuria-doesn’t always indicate pre-eclampsia
RENAL SYSTEM
Changes to ureters and bladder in pregnancy
Elongation to accommodate increased urine volume
Increased risk of urine infection (due to more urine)
Pressure on bladder due to increased fluid intake
Progesterone decreases bladder tone which can affect the sphincters
RENAL SYSTEM
How does progesterone affect bladder function?
It decreases bladder tone, increasing risk of infection by affecting the sphincters
GASTROINTESTINAL SYSTEM
Changes to appetite
Increased appetite and thirst at start of pregnancy
Hormonally controlled
Towards the end of pregnancy appetite and thirst decrease
GASTROINTESTINAL SYSTEM
Why does appetite decrease towards end of pregnancy?
Capacity for food due to gravid uterus - suggest smaller snacks
GASTROINTESTINAL SYSTEM
How do hormones affect hunger and thirst in pregnancy?
hCG affects hypothalamus leading to increased thirst
Progesterone stimulates hunger and thirst
GASTROINTESTINAL SYSTEM
what causes cravings (pica) in pregnancy?
Taste buds become filled in pregnancy
GASTROINTESTINAL SYSTEM
what may cause vomiting and nausea in pregnancy
Delayed stomach emptying as a result of progesterone reducing tone
GASTROINTESTINAL SYSTEM
why may your mouth become oedematous in pregnancy?
Increased blood flow due to oestrogen changing consistency of connective tissue
GASTROINTESTINAL SYSTEM
Changes to the mouth in pregnancy
Becomes more spongy due to increased blood flow
Can me oedematous
Saliva more acidic
GASTROINTESTINAL SYSTEM
Changes to the oesophagus and stomach in pregnancy
Heartburn (progesterone affecting tone of oesophageal sphincter)
Delayed stomach emptying (due to readuction in tone-progesterone)
GASTROINTESTINAL SYSTEM
Changes to intestines
Decreased tone
Increased absorption of substances (glucose, amino acids, iron etc)
Relaxation of smooth muscle in the colon =increased water absorption
Increased sodium reabsorption
Flatulence
GASTROINTESTINAL SYSTEM
what can cause constipation in pregnancy
Relaxation in smooth muscle of the colon increases water absorption causing constipation.
GASTROINTESTINAL SYSTEM
What 2 hormones cause increased sodium and water absorption from the colon
Angiotensin
Aldosterone
GASTOINTESTINAL SYSTEM
What causes increased flatulence in pregnancy?
Compression of the colon by the uterus
SKIN
How does skin change in pregnancy?
Pigmentation (increase in MSH)
Pruritus (itching)
Striae gravidarum (stretch marks)
SKIN
what causes stretch marks? (Striae gravidarum)
Rapid growth causes collagen fibres to stretch beyond their elastic limit
SKELETAL SYSTEM
What skeletal changes occur?
Increased absorption of calcium
Posture affected due to gravid uterus
Progesterone and relaxin affect lumber curve in spine causing lordosis
Oestrogen and relaxin affect cartilage composition- softens pelvis for labour
Symphysis pubis becomes more flexible
What causes carpel tunnel in pregnancy? (Tingling hands)
Nerve compression
Why may you snore in pregnancy?
Nasal mucosa becomes hyperaemic and congested- stuffy
How do sleep patterns change in pregnancy?
Increased desire to sleep
Deep (REM) sleep increases from 25 weeks
Sleep disturbed by nocturia
