Maternal Physiological Changes During Pregnancy Flashcards
(36 cards)
When do changes start during pregnancy? How are these changes controlled?
Most changes begin early (before pregnancy is even recognised)
Most changes are hormonally driven (Progesterone, oestrogen, renin-aldosterone, cortisol, insulin, human placental lactogen, prolactin)
Some mechanically driven (decreased lung capacity, vena caval compression)
What are the changes in physiology of a pregnant mother designed for?
To optimise conditions for foetus and prepare the mother for delivery.
What changes occur in the uterus during pregnancy?
Heigh + weigh (hyperplasia)
Uterine ligaments (stretch and hypertrophy)
Right dextro-rotation (tilts and twists to the right)
Lower segment (formed from isthmus during third trimester and reaches 10cm by term)
What changes occur in the cervix during pregnancy?
Becomes oedematous and congested
Eversion of columnar cells
Increased cervical gland secretion
Mucus plug (operculum)
What changes occur in the vulva during pregnancy?
Increased vascularity and varicosities.
What changes occur in the vagina during pregnancy?
Increased vascularity and distension at birth.
What changes occur in the ovary during pregnancy?
One ovary corpus luteum
Increased vascularity and size
What changes occur in the pelvic ligaments during pregnancy?
Relaxation of ligaments
Relaxation of pelvic joints
Pelvis becomes more mobile and has a larger capacity
What changes occur in the breasts during pregnancy?
Increase in size and vascularity
Increased pigmentation of the nipple
Secondary areola appear
Montgomery tubercles appear on areola (dilated sebaceous glands)
Colostrum expressed from as early as 16 weeks.
What are the endocrine changes that take place during pregnancy?
Pituitary: Increase in size and activity. Posterior pituitary releases oxytocin at the onset of labour and during lactation.
Thyoid gland increases size and activity. TBG levels double. Increase in total T3 and T4 (no change in free T3 and T4)
Parathyroid gland increases in size and activity.
Adrenal gland increases in size and activity and there is an increase in total cortisol.
What could go wrong following labour in the pituitary as a result of post-partum haemorrhage?
Mother becomes hypotensive and so the hypertrophied pituitary isn’t getting enough blood and this results in necrosis thus leading to hypopituitarism.
Why does progesterone drop after birth?
Loss of placenta which produces progesterone.
What do placental oestrogens do?
Induces growth of uterus
Responsible (along with progesterone) for breast development
Alters chemical constitution of connective tissues (more pliable)
Water retention
Decrease sodium excretion
What are the changes that happen to glucose metabolism during pregnancy?
Pregnancy is hyperlipidaemic and glycosuric
After mid-pregnancy insulin resistance develops due to raised cortisol and hPL
Plasma glucose concentration rises (4.5 - 5.5mmol/L)
Glucose crosses placenta (carrier) and is primary energy substrate for foetus
Concentration of glucagon and catecholamines unaltered.
What happens to protein metabolism during pregnancy?
Positive nitrogen balance
On average 500g protein retained by the end of pregnancy.
What happens to fat metabolism during pregnancy?
by 30 weeks 4kg stored in depot fat in abdominal wall, back and thighs, breasts.
Where do pregnanct women gain weight?
3kg in maternal stores of nutrients and muscle development
2kg in increased body fluid (1.5 - 2kg blood)
0.6 kg = Breast growth
1kg Enlarged uterus
1kg amniotic fluid
- 6kg placenta
- 4 - 4kg baby
Total = 11 - 16 kgs
What happens to skeleton during pregnancy?
More lax pelvic joints and ligaments (due to progesterone and relaxin) result in lumbar lordosis
Thorax gets wider
Center of gravity is altered
What happens to urinary system in pregnancy?
Size of the kidneys increases
Ureteral and renal pelvis are dilated by 8 weeks.
There is a decrease in urinary output (1ml/kg/hr)
Increased renal blood flow by 50 - 75%, GFR is higher by 50% and lower albumin in blood means lower colloid oncotic pressure.
What happens to renin production in pregnancy?
It is higher. (stimulated by progesterone)
Where is renin produced during pregnancy? What is the result of this production?
Made in the placenta resulting in net retention of Na+ and excretion of K+
Water retention is 6 - 8 liters.
Decrease in osmolality
Increased glycosuria.
Why does urinary output decrease during pregnancy even though the kidneys are working harder?
Mainly due to increase in aldosterone, progesterone, and oestrogen.
The overall result in an increase in tubular reabsorption.
What is the result of the increased glucose output in urine during pregnancy?
Increased UTIs, pyelonephritis, and oedema.
What are the GI changes during pregnancy?
Increased salivation
Altered taste
Increased appetite and thirst
Slowed Gi motility
Nausea/vomiting (proportional to HCG)
Constipation (decreased motility and increased water + salt absorption)
Decreased gastric acidity.
Relaxation of gastro-oesophageal sphincter resulting in reflux oesophagitis
