Pregnancy Flashcards
Normal human pregnancy is approx how long?
40 wks
How is the start of gestation measured?
Starts at the first day of last menstrual period for standardization purposes
1st trimester
day of conception-12 wks
2nd trimester
13-26th weeks
3rd trimester
26-delivery
Gestation
Indication of fetal dev from last period
Conception
Indication of dev from date the sperm fertilizes the ovum
Ovulation
Ovum (egg) released from ovary to fallopian tube
Zygote
Ovum fertilized by sperm, in fallopian tube
Blastocyst
- Cluster of 50-60 cells with a cavity to form a yolk sac
- Goal is to implant into uterine wall approx 5 days after fertilization
Placenta
Functional interface btwn mom and fetus that secretes hormones and growth factors into mom with physiological effects
Embryo
Cluster of cells once implantation happens
Organogenesis
- Embryo makes organs
- Takes 10 weeks
When are organs developed, heartbeat, moves arms and legs, 8 cm long, weighs 13 g?
10 wks past conception
When does the baby grow rapidly moves freely, hiccups, can yawn, genitalia visible, release functional sex hormones?
2nd trimester
When can premature births survive if sufficient prenatal care is available?
26th week of gestation
When does the fetus gain 200 g/wk (7 oz), eyes open and blink, practice breathing, sucking reflex at 34 weeks?
3rd trimester
When does the baby mainly dev muscle, build fat storage, practice movements required for life after delivery?
Last 4 weeks of gestation
When does delivery happen?
38-42 wks
Describe hormone changes throughout pregnancy
- Progesterone increases throughout pregnancy until close to term when levels drop (needed to maintain pregnancy)
- Estrogen levels rise as progesterone levels drop
- Oxytocin triggers uterine contractions
Plasma volume during pregnancy
- Steady increase over course of pregnancy directly proportional to fetus weight in 3rd trimester
- More vol to compensate for baby growth
- PV increase 50-85% compared to pre-pregnancy
- Extracellular vol increase 30-50%
- Increase helps maintain BP, dilutes out peripheral whole blood which falsely appears to decrease RBC count
RAAS transformation during pregnancy
- Activated during pregnancy
- Underfilling of arteries and release of relaxin
- Hypothalamus releases AVP/ADH from posterior pituitary
- Aldosterone secreted by adrenal glands to retain Na (increases PV)
Relaxin
Hormone produced by ovaries and placenta that helps body stretch for delivery
Which analytes decrease during pregnancy?
- Iron (Hgb synthesis)
- Iodine
- Protein catabolism (increased LDL by liver)
- Calcium
Why is calcium important for the fetus?
- Needs 30-50 g/day of free calcium
- Calcium released by mom’s bones if sufficient calcium unavailable in mom’s circulation (can have dental problems after)
Which hormones/steroids increase in pregnancy?
- Estradiol
- Prostaglandin
- Endothelium-dep factors cause peripheral dilation
- Relaxin
- Prolactin
- Hormones affecting insulin sensitivity in mom (human placental lactogen, GH, progesterone, cortisol, prolactin)
T/F
Cardiac output increases 20% by 8 weeks and maternal heart rate increases 10-20 bpm
True
Glomerular filtration rate during pregnancy
- GFR increases due to vasodilation and increased PV
- More filtration of creatinine, uric acid, and BUN -> decreases plasma levels
Serum creatinine in pregnancy
0.5 mg/dl
Serum BUN in pregnancy
8.9 mg/dl
Hyperventilation during pregnancy
- Increased demand for O2
- Increased pO2 and decreased pCO2
- Normal to have mild, fully compensated resp alkalosis
Cholesterol levels during pregnancy
Increased triglycerides and LDL
