Pregnancy Flashcards

Question

Maternal blood

Answer 1

-maternal plasma volume increases by 45% -red cell mass increases by 18% => which increases the efficiency of iron absorption from gut and hemodilution apparent anemia bc Hb conc falls (bc plasma volume is increased from 4.5L to 6L) =>increase in white cells and clotting factors, blood becomes hypercoaggulated, fibrinogen for placental separation, but increased risk of thrombosis.

Answer 2

1. Expanding uterus pushes heart changes ECG and heart sounds 2.Peripheral vasodilation mediated by endothelium dependent factors such as nitric oxide synthesis upregulated by E2 20-30% fall in TPR so CO increases... 3. Increased cardiac output increased heart rate (8-10bpm) but primarily stroke volume begins as early as 3 weeks to max 40% at 28 weeks BP decreases in 1st 2 trimesters. =>Extra work exacerbates pre-existing heart conditions, eg aortic valve defects, pulmonary hypertension.

Answer 3

Increased cardiac output and vasodilation by steroids- E+P Reduced peripheral resistance and increased flow to: Neoangiogenesis, including extra capillaries in skin (spider naevi) to assist heat loss. Pregnancy characterised by low pressure and high blood volume. => CO = BP/TPR => CO= HR xSV

Answer 4

steroid causes : -appetite and thirst - reduced GI motility => constipation -relaxed lower oesophageal sphincter => acid reflux -large uterus (expanding)

Answer 5

-Supplementation advised up to 400μg/day until week 12. Ideally 3 months before pregnancy. Deficiency can lead to birth defects eg spina bifida (neural tube defects).

Answer 6

increased filtration rate = increased clearence of creatinine, urea, uric acid , glucose reabsorbtion less effective -Relaxin from corpus luteum/placenta stimulates formation of endothelin which mediates dilation of renal arteries by nitric oxide synthesis. -Progesterone and VEGF cause resistance to angiotensin II mediated vasoconstriction leading to further vasodilation and increased renal blood flow and increased GFR.

Answer 7

increases thirstier than normal high blood volume increased filtration rate urethra relaxed

Answer 8

CRH: CRH released into maternal and foetal circulation by placenta. Increases cortisol (positive feedback) and stimulates adrenocorticotrophic hormone (ACTH) & so DHEA in foetal HPA axis. DHEA (androgen) is aromatized into estrogen by the placenta. Increasing E:P ratio and stimulating prostaglandins which activate blood flow, uterine contractions & cervical ripening. placenta cant make eostrogen directly it has to make it by aromatisation. =>This is one of the things that triggers labour

Answer 9

Cortisol: -adrenal gland produces cortisol which feedbacks on the placental to increase CRH which stimulates ACTH so DHEA and then aromatisation occurs changing E: P ratio. -metabolic changes (insulin resistance). - Foetal lung maturity - mineralocorticoid action (aldosterone) -increased prostaglandin E2 and oxytocin production by placenta. -cortisol helps foetal lung maturity -surfactant distrupts hydrogen bonds, reduces surface tensions and opens up alveoli

Answer 10

-increased production of thyroid hormone to meet increased metabolic demand of pregnancy leads to a risk of gestational thyrotoxicosis, hCG may act on TSH receptor. If patient has a history of hyperthyroidism such as Graves disease they may require endocrine management to maintain normal function. Biochemical tests may indicate hyperthyroidism in pregnancy where in fact the patient is normal (euthyroid). Symptoms can include anxiety, tremor, heat intolerance, palpitations, weight loss or lack of weight gain, goiter, tachycardia, and hyperreflexia but usually associated with persistent vomiting of hyperemesis gravidarum. Suppressed TSH and high serum T4 may indicate gestational thyrotoxicosis. =>The major form is thyroxine (T4), which has a longer half-life than triiodothyronine (T3). T4 is converted to the active T3.

Answer 11

At 12 weeks gestation the uterine fundus may be palpated through the abdomen above the symphysis pubis. Large increase in muscle mass during first 20 weeks (50g – 1000g). After this stretching & increases in blood flow; size reaching a peak at 36 weeks. size of a pear => watermelon

Answer 12

Primary function is to retain the pregnancy Increase in vascularity Tissue softens from 8 weeks changes in connective tissue begins gradual preparation for expansion Proliferation of glands mucosal layer becomes half of mass great increase in mucus production Protective ie anti-infective

Answer 13

High circulating concentrations of estrogen and progesterone increase prolactin levels during pregnancy. Part of a family with human placental lactogen and growth hormone – all have widespread metabolic effects. During pregnancy prolactin is produced by myometrium and placenta, in addition to the pituitary. Estrogen and progesterone inhibit the stimulatory effects of prolactin on milk production. The abrupt drop in estrogen and progesterone levels following delivery allow prolactin to induce lactation. After birth, sucking activates nipple mechanoreceptors signaling the hypothalamus and causing anterior pituitary prolactin secretion. oestrogen and progesterone inhibits prolactin inducing lactation but the major drop in E and P after birth is what induces prolactin to cause lactation.

Answer 14

Stretching of uterus and cervix during childbirth causes release of oxytocin which helps with the birth and emotional bonding with the baby. Suckling stimulus triggers the release of oxytocin from the posterior pituitary gland, which triggers milk ejection. Prolactin controls milk production (lactogenesis) but the milk-ejection reflex is due to oxytocin.

Answer 15

Dramatic and rapid fall in steroids on delivery of the placenta. Most endocrine-driven changes return to normal rapidly. Uterine muscle rapidly loses oedema but contracts slowly: never returns to pre-pregnancy size. Removal of steroids permits action of raised prolactin on breast.