Pregnancy Physiology Flashcards
describe aspects of CV adaptation to pregnancy
- blood vol increases (35%)
- syst. vasc. resist decr. (15-21%)
- CO, SV, HR, all incr
- BP dec, hgb decr
what cell types are resp for remodeling of the spiral arteries
extravillous cytotrophoblasts
the spiral arteries in pregnancy are remodeled to allow ?
high flow, low resistance
systemic vasculature during pregnancy undergoes what type of changes?
less fibrin, more elastin = reduced vasomotor tone = incr. compliance - total periph. resistance is decr. 20-25%, this decr in afterload contributes to the incr. CO.
-MMPs contribute to this process by remodeling the ECM around the arteries
decidualization of the endometrium is?
cells have become lg pale cells susc. to invasion by the trophoblasts
what factors control vasc. remodeling and when is it completed by what time?
- hCG, P4(prog), E2, also antiangiogenic factors like sol. VEFGRs and endoglin are nmly decreased whereas PlGF (pl. growth factor) is increased. These may look diff. in pts w/ preeclampsia
- placental remod. is done by 20 weeks, but maternal adaptation cont. til the end
why does hct drop during pregnancy?
b/c the plasma vol incr. more compared to the incr in erythrocytes and thus the ratio is lower, hct lower. physiologic anemia
changes in the heart during pregnancy
ventricular remodeling = physiologic left vent. hypertrophy which is caused by an incr. in cardiac myocytes w/o fibrin deposition. this is similar to the effects seen in exercise.
-ANP and BNP are rel from the heart musc in resp to stretching
GFR changes in pregnancy
GFR increases w/ the incr. in CO and blood flow. Nml Cr may be avg of 0.4 instead of 0.9. Also, the pressure of the fetus can cause dilation of the urinary collection system = hydronephrosis
Respiratory changes during pregnancy
the diaphragm is elev, the ribs expand and respiration becomes more diaphrgmtic.
Total lung capac is decr, and dead space is incr - so the RR incr. to blow off the CO2 that would otherwise accumulate and 02 intake incr.
Nml ABG values in pregnancy
Ph 7.4-.45, pCO2 = 28-32, pO2 = 101-106, HCO3 = 18-21 this is a slight respiratory alkalosis with a metabolic compensation.
Hormonal changes in prenancy related to fat and metabolism
Pregnancy looks v. similar to obesity. Leptin, TNF-a, and Cort all incr. and they display insulin and leptin resistance resistance. Insulin resistance may contribute to incr. circulating levels of fats, etc which may contribute to their transport across the placenta.
majority of leptin incr. in preg comes from
the placenta
when cort is increased in preg, how does this affect the fetus?
Cort is inactivated in the placenta by 11BHSD2 which conv. it to inactive corticosterone and so the fetus is no affected. Cort in the mother may incr. circ levels of FFA’s and contribute to fat deposition in the fetus. if there is a problem with this enzyme it can lead to problems, growth restriction.
sev. mech of maternofetal transfer located on the syncytiotrphblst which has microvilli projecting into the intervillous space which is where the maternal blood pools=
- endo/exocytosis = ex. immunoglobulins
- lipophillic diffusion = resp. gases
- paracellular diff. = hydrophobic molecules, eg. Na, Ca, K
- prot-med. transport = AAs (FA transport prot), Glc (GLUTs), etc.
how are lipids transfered across the placenta
there are extracellular lipases on the same syncytiotrophblst membrane that rel. the FAs from the maternal circ and binding prots in the sct guid them across to the fetal capillaries.
interactions btwn the mat. and fetal resources/demands are mediated by the placenta and things like enzymes, GFs, blood supply, etc
yes.
a fetus is viable (able to live outside the uterus) at what week?
24
preterm =
24-37 wks (note: 37 may be considered “early term” not pre anymore
late term
41
post term
42
progressive monitoring of mother incl:
Rh, Wgt gain, BP, DM, anemia, group B strep assesmt, delivery plan
nml weight gain
25-30 lbs for a singleton
obesity is a form of ____________
malnutrition, esp. AA’s.
essential AA’s
Histadine, Isoleucine, Leucine Lysine, Methionine and Cysteine Phenylalanine and Tyrosine Threonine Tryptophan Valine
What type of BP med is contraindic. in preg.
ACEi’s. %50 congenital malformations if during the first 12 weeks while organogenesis is occuring.
gestational htn
benign, outcomes good
pre-eclampsia
not benign,HTN, proteinuria (500 mg/day), only due to pregnancy, w/o tx progresses to eclampsia (convulsions) and death. Doesn’t present b4 20 weeks and not found in any other mammal.
tx for Rh mismatch
rhogam, antibody which coats the fetal red cells so that the maternal antib. don’t recog. the fetus as foreign
risk factors for gest. DM
prior DM in pregnancy,
multiple gestation,
Adv. maternal age,
Obesity
structure of hCG similar to _____and ______
TSH and insulin
phases of labor
- latent - pre-labor = 4 cm
- active phase (1st) - 4-10 cm (1-2 cm per hour)
- pushing (2nd) - 3hr primip, 2 hr multip
- delivery of placenta (3rd) - 1 hr
7 cardinal mvmts of delivery
- engagement - head w/ pelvis
- descent - into pelvis
- flexion - chin to chest
- int. rotation - face toward posterior
- extension - delivery of the head
- restitution - external rotation, head back toward side/front
- expulsion - delivery of ant shoulder, then post.
vessels in the cord
2 arteries and 1 vein
perineum lacerations
1st degree – Skin only
2nd – Defect of underlying tissue but not through anal sphincter
3rd - Into or through sphincter
4th - Defect of rectum
rate of C/S in US births
33%, 20% for primigravidas
VBAC, risks
vag. birth after c-section, uterine scar weakens the musc - rupture, repeat C/S can incr. scarring, adhesions, complications,
risk of C/S
incr. bleeding, infection, intraabdominal scarring, risk of uterine rupture w/ each cs incr., risk of placenta accreta - placenta invades completely thru the endometrium and into the myo esp in the presence of scar tiss.
maternal mortality ratio
deaths/ 100,000 live births in one year
