Maternal Adaptations to Pregnancy

Question 1

Human placental lactogen (HPL)

Answer 1

• polypeptide, similar to GH and Prl
• rises steadily throughout pregnancy
• can also be positive with bronchogenic carcinoma, hepatoma, lymphoma and
  pheochromocytoma
• functions include lipolysis, inhibition of glu uptake, anti-insulin
• not required for successful pregnancy

Question 2

Human Chorionic Gonadotropin (hCG)

Answer 2

• glycoprotein, 2 subunits, alpha is similar to FSH/LH/TSH, beta is specific
• increases with multiple gestations, erythroblastosis, hydatidiform mole,
  choriocarcinoma
• actions: prolongs life of corpus luteum, inc. steroid production; used as a dx test for pregnancy

Question 3

The placental hormones

Answer 3

HPL, hCG, LHRH, TRH, E, P

Question 4

Cervical changes during pregnancy

Answer 4

• Softening and cyanosis
  
  • Increased vascularity
  • Edema
  • Hypertrophy and hyperplasia of glands
• Erosions
• Cervical mucus
• Histology
• Connective tissue

Question 5

Chadwick’s sign

Answer 5

Violet blue color of the vaginal mucosa ⇒ presumptive sign of pregnancy

Question 6

Uterine changes during pregnancy

Answer 6

• Weight - ~1,000g heavier
• Volume
• Type of uterine muscular growth - wall thins from ~10 to 5.5mm
• Stimulus for growth
• Uterine position changes
• Uterine contractions
• Uterine blood flow - inc. from about 100 to 600 ml/min
• Cervical changes

Question 7

Ovaries/oviduct changes during pregnancy

Answer 7

The ovaries:
• Ovulation
• Corpus luteum
• Relaxin
• Luteoma
• Decidual reaction 
• Engorgement of ovarian veins
The oviducts:
• Flattened epithelium
• Decidual cells but no continuous decidual reaction

Question 8

Maternal endocrine changes during pregnancy

Answer 8

• RAAS is much more active
• increased PTH, Vit D, Ca absorption; dec. total but normal ionized Ca, normal calcitonin
• thyroid enlarged but TSH/function normal, inc. TBG capacity, normal T3/T4, inc. BMR
• pituitary enlargement, GH is low around delivery and remains low; Prl inc. in preg, drops after delivery; oxytocin inc. with gestational age
• adrenal hormones increase throughout preganancy

Question 9

Fetal endocrine changes during pregnancy

Answer 9

• PTH at 12-13wks, low till term; Ca falls postpartum, calcitonin normal, 25(OH)D normal, 1,25(OH)2D low at term, inc. first 48 hrs
  - TSH normal at term, thyroid functions at 12-16wks; TBG capacity, T3/rT3 inc. at term, free T4 normal at term, T3 normal by 1st week

Question 10

Metabolic changes in pregnancy

Answer 10

• Weight gain
• Protein metabolism - aa’s increase in fetus
• Carbohydrate metabolism - insulin resistance in mom
• Fat metabolism - fat consumed whenever possible, inc. FFAs
*Average weight gain is 11kg (24lbs) accounted for by the fetal tissues and increased maternal tissues (uterus, breast, blood, EVF, and fat)

Question 11

Urinary tract changes during pregnancy

Answer 11

• kidneys increase in size by 1.5cm, inc. GFR, RBF, cre clearance, dec. BUN; glucosuria, proteinuria
• ureter dilates, elongates, dec. urine flow
• bladder inc. in size and blood vessel tortuosity, elevation of trigone, inc. pressure from uterus

Question 12

CV, respiratory changes during pregnancy

Answer 12

• diaphragm is elevated at term, decreasing TLC/VC
• Heart displaced/rotated laterally, widely split S1 (85% with S3; 90% soft, mid-systolic flow murmur), atrial/ventricular extrasystoles
• CO inc. 4.5–>6L/min because of inc. SV, dec. TPR; theory = the fetus itself is like an AV fistula, inc. plasma volume, and hormonal changes

Question 13

CV changes at delivery

Answer 13

• during labor: 30% increase in CO at first stage, then more in second stage; with anesthesia (pain relief) CO will dec.
• inc. in CO comes from inc. SV when pressure on IVC is relieved, and uterine contraction/autotransfusion

Question 14

Hemodynamic changes during pregnancy

Answer 14

• dec. RBC life span, dec. O2 affinity
• increased reticulocytes, RCV, EPO; erythroid hyperplasia of BM–>requires more iron
• plasma volume inc. 45% (rapidly in 2nd trimester); Hct dec. 5-6%
• Hgb may dec but

Question 15

Liver, Gallbladder, and Esophagus changes during pregnancy

Answer 15

Liver:
• Alkaline phosphatase doubles 
• ↓ plasma albumin
• ↓ cholinesterase activity
• No change hepatic blood flow, bilirubin, or morphology
Gall bladder:
• Distension 
• Hypotonic 
• Thickening of bile
Esophagus:
• pressure ~15mmHg until week 36 (~3mmHg), then peaks postpartum (~25mmHg)

Question 16

Breast changes during pregnancy

Answer 16

• Tenderness
• Increased size, nipple size
• Nodularity
• Clostrum
• Areolar changes
• Montgomery glands

Question 17

Musculoskeletal changes during pregnancy

Answer 17

• Lordosis
• Increased joint mobility
• Low back pain
• Postural changes
• Weight gain
• Pressure on joints
• Weakening of ligamentous supports

Question 18

Skin changes during pregnancy

Answer 18

Blood vessels: Vascular spiders, venous varicosities, palmar erythema
Hyperpigmentation:
• Nevi
• Chlosma ⇒ mask of pregnancy
Hair:
• Anagen (growth) normally lasts 2 – 6 years
• Telogen (resting phase): 15 – 20% usually; falls to 10% late pregnancy (2nd and 3rd trimesters); increases to 30% postpartum ⇒ most hair lost 2 – 4 months postpartum

Question 19

Abdominal wall changes during pregnancy

Answer 19

Striae gravidarium:
• Reddish slightly depressed skin streaks
• 50% pregnant women
• Silver streaks
• Unrelated to degree of skin stretching alone - requires striae factor

Diastasis recti - separation of rectus muscles in midline
• Linea nigra
• Midline, darkened skin line