Maternal adaptation to pregnancy Flashcards
early in pregnancy, changes may be considered ______
whereas later they may be considered as ______
anabolic = early
catabolic = later - mobilsiation of fuel reserves, as demands of fetus are high
how do oestrogen and progesterone show synergy?
oestrogens increase the expression and sensitivity of the progesterone receptor.
Progesterone, hCG and hPL are produced by the _______
Progesterone, hCG and hPL are produced by the placenta
the oestrogens are synthesised by a ….
the oestrogens are synthesised by a feto-placental unit
where does proactin come from?
maternal pituitary
does progesterone increase throughout the pregnancyu?
increases consistently to term
describe the effects of the early sex hormone changes in pregnancy
These merge with the luteal phase of the ovarian cycle.
Progesterone suppresses menstruation, uterine contractions and hypothalamic cycling.
Oestrogens increase uterine blood flow and vessel growth.
Together, these two steroids cause growth of the uterus and mammary tissue (see Lactation lecture).
describe the effects sex steriod changes have - mid gestation.
how does the soruce of progesterone change?
Rising progesterone and oestrogen levels continue to stimulate uterine and mammary growth without stimulating function.
Source of progesterone changes from ovary to placenta at 12-16 weeks. This is a vulnerable period for maintaining a pregnancy.
describe the late gestational changes due to changes in levels of sex sterioda
In most mammalian species, there is a fall in progesterone and an increase in oestrogen concentrations before parturition but this does not appear to occur in women, although changes in the oestrogen to progesterone ratio may occur at the tissue level.
diagram for effects of progesterone, progesterone + oestrogen, and oestrogen
the production of prolactin leads to enlargement of what?
the maternal pituitary anterior gland
does prolactin levels increasing elad to changes in the strucutre of the mammary glands?
yes
problems with pituitary enlargement due to increased prolactin secretion?
Pituitary enlargement may cause visual problems through pressure on the optic chiasma, and renders the gland vulnerable to ischaemic necrosis in the event of post-partum haemorrhage or similar vascular incident
whats Sheehans syndrome?
Sheehan’s syndrome is a condition that affects women who lose a life-threatening amount of blood in childbirth or who have severe low blood pressure during or after childbirth, which can deprive the body of oxygen.
This lack of oxygen that causes damage to the pituitary gland is known as Sheehan’s syndrome
role of human placental lactogen?
Produced by the syncytiotrophoblast of the placenta.
hPL stimulates maternal appetite, lipolysis and maternal utilization of fat in preference to glucose, and growth of the mammary tissue.
how is relaxin important in pregnanyc?
origin: corpus luteum, placenta, decidua
actions: vasodilator, softens ligaments and cervix in late pregnancy
describe leptins importance in pregnancy
Leptin is secreted by the placenta, but pregnancy is a state of peripheral leptin resistance, allowing for deposition of fat stores
how are fetal caclium demands met?
Fetal demands are met mostly by increased Ca++ uptake from the maternal gut, with some release from the maternal skeleton towards term when mineralization of the fetal skeleton is at a peak.
Calcium excretion in maternal urine actually increases, and double by term.
describe how adrenal cortical hormones are involved in pregnancy
Adrenal cortical hormones.
Increased concentration of cortisol and aldosterone due to an oestrogen stimulated increase in binding globulins, and CRH from the placenta.
describe the role of pregnancy-associated plasma protein A in pregnancy?
origin: placenta
actions: protease that cleaves IGF binding protein and so regulates availability of IGF. Low values associated with fetal growth restriction
Maternal pituitary gland increases in size by ____% in pregnancy
Maternal pituitary gland increases in size by 30-50% in pregnancy
describe how the adrenal gland cahnges in function during pregnancy
- Increased activity of the renin-angiotensin system leads to a rise in aldosterone
- There is a ~3 fold rise in cortisol levels after the first trimester, both free and bound
- Rise in cortisol driven primarily by corticotropin releasing hormone (CRH) secreted by the placenta
- Cortisol may contribute to the hyperglycaemia seen in pregnancy
give 5 broad physiological categories for change during pregnancy
Cardiovascular
Respiratory
Renal
Metabolic
Physical
how does cardiac function change during pregnancy
- Increased CO (both SV and HR increase)
- occurs early in first trimester - most likely in respone to maternal vasodialtion
- mainly to tissues with increased demand e.g. reproductive tissue (uteroplacental circulation), gut (increased food uptake), kidney (excretion of waste) and skin (dissipation of heat generated by fetus).
*
T or F
Pregnant uterus may impede venous return in certain postural positions.
T
describe how blood volume changes during pregnancy
- 1st 2 trimersters: 40% increase in maternal blood - to fill dilated maternal circulation
- due to upregulation of the renin-angiotensin system and increased sodium and water retention by the kidney.
desribe how the blood composition changes during pregnancy
- blood volume increases = haemodilution
- then RBCs rise in count due to erythropoietin
- no change in RBC half life
- alsdo dilution of platelets
- risk of thromboelbolic disease - as fibrinolysis is decreased due to PAI-2 being released form the placenta
how does blood pressure change during pregnancy?
decrease in early-mid pregnancy and then an increase towards term
- Decrease due to the vasodilation of maternal circulation due to relaxin and progesterone mediated smooth muscle relaxation, and increased nitric oxide synthase activity, coupled with reduced peripheral responsiveness to angiotensin II
*
what is pre-eclampsia
Pre-eclampsia is defined as de novo hypertension of 140/90 mmHg starting after 20 weeks of gestation. Some older definitions include proteinuria (>300 mg in 24 hours) and peripheral oedema.
The syndrome is characterized by generalized endothelial cell activation in response to factors released by a poorly perfused placenta.
might there be heart murmurs during pregnancy
The increased cardiac output can lead to systolic murmurs as the blood flows over the aortic and pulmonary valves.
during pregnancy the heart becomes more powerful - by which grworth mechanism?
Achieved by eccentric hypertrophy, which takes 6 months to return to normal after delivery
Uterus may compress the vena cava in the _____ position
impeding venous return
Uterus may compress the vena cava in the supine (sup) position,
impeding venous return
give some reasons peripheral resistance drops during early pregnancy
Peripheral resistance drops due to
- relaxin from corpus luteum,
- progesterone-mediated smooth muscle relaxation,
- stimulation of NO pathways,
- and blunting of peripheral responses to angiotensin II and noradrenaline
The amount of angiotensin-II required to evoke a pressor response _________ during pregnancy compared to the non-pregnant mean
The amount of angiotensin-II required to evoke a pressor response increases during pregnancy compared to the non-pregnant mean
aka less sensitive / blunting
where is most of the CO out delivered to ?
Most of the increase in cardiac output is directed to uterus and placenta (17% of cardiac output at term versus 2% in the non- pregnant) at expense of splanchnic bed and skeletal muscle
platelets count is _____ during pregnancy?
reduced
describe how preganncy affecst total lung capacity?
reduced due to elevation of the diaphragm
describe how pregnancy affects tidal volume?
increased as excursion of the diaphragm is increased due to stimulation of central chemoreceptors by progesterone.
Also, the circumference of the thorax is increased due to relaxation of ligaments
how far is the diaphragm elevated?
4cm ish
pregnancy leads to an increase in thorax circumference by ___ cm
ncrease in thorax circumference by 5-7 cm
does the respiratory rate change during pregnancy?
no
tidal volume increases ____% by 8 weeks gestation
tidal volume increases 30-50% by 8 weeks gestation
how do blood gases change during pregnancy?
Maternal oxygen consumption increases to meet fetal and her own demands.
Arterial PO2 remains fairly constant but PaCO2 decreases due to increased alveolar ventilation.
Develop a chronic respiratory alkalosis that favours CO2 transfer from the fetus.
respiratory changes picture
describe the renal chances during pregnancy
There are increases in GFR associated with increased renal plasma flow.
Pregnancy is a state of positive Na+ balance to meet fetal requirements and stimulate plasma expansion.
Maintained by increasing aldosterone secretion.
Glucosuria may occur due to reduced glucose transporters in the proximal tubule.
Urinary protein also increases, but should not exceed 300 mg in 24 hours.
Increased erythropoietin production.
describe the metabolic changes during pregnancy
There is an increased requirement for nutrients and fat deposition to support fetal growth in late gestation and lactation after birth . The metabolic changes are induced by the sex steroids, placental GH variant and cortisol.
during pregnancy GFR increases by hoew much?
50%
why does renal GFR increasE?
Principally due to changes in renal NO, induced in part by relaxin, causing reduced pre- and post- glomerular arteriolar resistance
Maternal creatinine and blood nitrogen concentrations —— increase or decreasE?
Maternal creatinine and blood nitrogen concentrations fal
Appetite is ________ in early pregnancy, aiding laying down of nutrient reserves
Appetite is increased in early pregnancy, aiding laying down of nutrient reserves
T or F
Nausea and vomiting (morning sickness) complicates 50-90% of pregnancies during first trimester
T
is there an increased risk of gastric reflux during pregnancy?
why?
Relaxation of the oesophageal sphincter due to progesterone, in combination with the enlarged uterus, increase the risk of gastric reflux in pregnancy
describe how bowel motility changes during pregnancy
Motility of the small bowel is reduced, and probably of large bowel too, through oestrogen-induced NO activity
may pregnant people get constipated?
yes
Iron and calcium absorption is ______ during pregnancy?
Iron and calcium absorption is increased
gall stones during pregnancy?
Relaxation of smooth muscle in the gallbladder favours cholestasis and formation of gallstones (10% of pregnant women)
how is liver affected during pregnancy?
Liver size and function largely unchanged
describe some of the behavioural changes during pregnance?
- Early behavioural changes relate to food acquisition e.g. increase thirst and appetite, cravings and aversions, nausea and vomiting
- Late behaviour changes: sense of fatigue, reduced food intake, nesting/restless behaviour
- Caused by rise in sex steroid hormones, PL/prolactins
Maternal metabolism is modulated during pregnancy in order to:
(3)
- •ensure adequate growth and development of the fetus
- •meet the altered demands of the mother during the pregnancy
- •provide the mother with sufficient reserves for labour and lactation
Basal metabolic rate (in resting state) increases from approx. ____ kcals/day to _____ kcals/day in women with an average preconception BMI
Basal metabolic rate (in resting state) increases from approx. 1,300 kcals/day to 1,700 kcals/day in women with an average preconception BMI
The principal metabolic substrate for the feto-placental unit is ______, and so many of the adaptations revolve around increasing the supply available for placental usage and transport
The principal metabolic substrate for the feto-placental unit is glucose, and so many of the adaptations revolve around increasing the supply available for placental usage and transport
how is maternal insulin affected during pregnancy?
Hormonal changes cause maternal insulin resistance.
Glucose is, therefore, diverted to the fetus.
pregnancy is a state of _______ inflammation)
pregnancy is a state of increased inflammation)
fun fact yano
Peripheral insensitivity to _____ allows fat deposition in early pregnancy.
Peripheral insensitivity to leptin allows fat deposition in early pregnancy.
describe changes to glucose tolerance as pregnacny progersses
There is a progressive deterioration in glucose tolerance as pregnancy advances
T or F
Some women develop gestational diabetes
T
describe hanges in Beta cells during pregnancy
- There is a progressive development of insulin insensitivity in peripheral tissues; muscle, adipose tissue
- ß cells in pancreas proliferate and hypertrophy in response
which hormones is important for beta cell adaptations?
hPL important for ß cell adaptations
There is a progressive _____ in plasma lipids as pregnancy advances, particularly ______
There is a progressive rise in plasma lipids as pregnancy advances, particularly triglycerides
how does the mother preserve glucose for the fetus?
Maternal beta oxidation of fats preserves glucose for the fetus
describe pregnancy weight gain
weight during pregnancy due to fetus and placenta, fat deposition, growth of reproductive organs and accumulation of fluids
Weight gain.
- an average of about 12.5 kg (range 7 - 23 kg).
- depends on diet, exercise etc.
- younger women tend to gain more weight than older ones,
- light women tend to gain more weight than heavy ones.
Lordosis - what is it
Lordosis is defined as an excessive inward curve of the spine. - back curves out more
increase in lordosis to maintain the centre of gravity over the hip joints
give some behaviorual changes assoicated with pregnancy
- Early behavioural changes caused by rise in sex steroid hormones and relate to food acquisition e.g. increase thirst and appetite, cravings and aversions, nausea and vomiting.
- Late behaviour changes. Sense of fatigue. Reduced food intake, nesting/restless behaviour.
