SM_208b: Normal Pregnancy Flashcards
Describe physiological changes in the uterus during pregnancy
Physiological changes in the uterus during pregnancy
- Progressive increase in uteroplacental blood flow as gestation progresses
- Uterine weight increases as well
- Estrogen-mediated hypertrophy
- Progesterone-mediated relaxation
Describe physiological changes in the cervix / vagina during pregnancy
Physiological changes in the cervix / vagina during pregnancy
- Chadwick sign
- Hypertrophy and hyperplasia of cervical glands -> eversion of proliferating columnar endocervical glands
- Increasing mucosal thickness and loosening of connective tissue in vagina
Chadwick sign is ____
Chadwick sign is bluish discoloration of the cervix and vagina caused by increased blood flow
- Observed as early as 6-8 weeks after conception
- Early sign of pregnancy
Describe physiological changes in the ovaries during pregnancy
Physiological changes in the ovaries during pregnancy
- Corpus luteum functions until 7 weeks gestation
- Decidual reaction
- Theca lutein cells: associated with high hCG levels, bilateral cystic ovaries, maternal virilization occurs in 25%
Theca lutein cysts in the ovaries are ____, ____, and ____
Theca lutein cysts in the ovaries are associated with high hCG levels, bilateral cystic ovaries, and maternal virilization occurs in 25%
Decidual reaction in ovaries is ____
Decidual reaction in ovaries is an increase in secretory functions of the endometrium at the area of implantation and edematous surrounding stroma
- Seen in very early pregnancy in generalized area where blastocyst contacts endometrial decidua
In pregnancy, cardiovascular changes include ____, ____, and ____
In pregnancy, cardiovascular changes include enlarged cardiac silhouette due to elevation of diaphragm, increase in HR, and increase in CO
MAP is lowest in ____ of pregnancy
MAP is lowest in middle of pregnancy
In pregnancy, elevation of diaphragm ____ respiratory function
In pregnancy, elevation of diaphragm changes respiratory function
Describe maternal GI tract physiology in pregnancy
Maternal GI tract physiology in pregnancy
- High B-hCG contributes to nausea / vomiting in first trimester
- Increasing smooth muscle relaxation secondary to progesterone: GERD, constipation, decreased gallbladder motility
- Gastric emptying time itself unchanged in pregnancy but increases during labor
Describe maternal hepatic physiology during pregnancy
Maternal hepatic physiology during pregnancy
- Increased hepatic blood flow
- Labs: D-dimer increases, alk phos increases, albumin decreases
- Anatomic changes: appendix location
Pregnancy effect on hepatic labs
- D-dimer: ____
- Alk phos: ____
- Albumin: ____
Pregnancy effect on hepatic labs
- D-dimer: increases
- Alk phos: increases
- Albumin: decreases
Describe maternal renal / urinary physiology during pregnancy
Maternal renal / urinary physiology during pregnancy
- GFR increases by ≤ 50% by mid-pregnancy
- RPF increases more than GFR
- Serum Cr decreases
- Uterine displacement of ureters (R>L): hydronephrosis, slight increase in size of kidneys
Maternal blood volume ___ during pregnancy
Maternal blood volume increases during pregnancy
Describe maternal hematologic physiology during pregnancy
Maternal hematologic physiology during pregnancy
- Leukocytosis in pregnancy
- Increased granulocytes and CD8 lymphocytes
- Decreased CD4 lymphocytes and monocytes
- Coagulation / fibrinolysis: both augmented but remain balanced for homeostasis
- Clotting factors increase, tPA increase, protein S decreases, activated protein C decreases
Pregnancy effect on coagulation labs
- Clotting factors (including fibrinogens): ____
- tPA: ____
- Protein S: ____
- Activated protein C: ____
Pregnancy effect on coagulation labs
- Clotting factors (including fibrinogens): increase (except factors XI and XIII)
- tPA: increase
- Protein S: decrease
- Activated protein C: decrease
Most circulating hormones are ____ in pregnancy as a result of the fetus and placenta
Most circulating hormones are increased in pregnancy as a result of the fetus and placenta
Describe maternal endocrine physiology during pregnancy
Maternal endocrine physiology during pregnancy
Describe effect of pregnancy on thyroid hormone
Effect of pregnancy on thyroid hormone
- TBG: increased
- T4 and T3: increased
- TSH: stable / slightly decreases
(fetus dependent on maternal thyroid hormone until at least 10 weeks gestation)
Describe maternal metabolic physiology during pregnancy
Maternal metabolic physiology during pregnancy
- Basal metabolic rate increases 10-20%
- Weight gain: 25-35 lbs if normal pre-pregnancy weight, maximal additional caloric intake is 300 kcal / day
- Carbohydrate metabolism: hyperplasia of insulin-secreting pancreatic beta cells, increased insulin secretion, progressive insulin resistance -> mild fasting hypoglycemia and postprandial hyperglycemia
- Protein metabolism: nitrogen balance increases with GA
- Fat metabolism: increased lipids / lipoproteins / apolipoproteins, fat storage occurs primarily mid-pregnancy and tends to be deposited more centrally
Maternal metabolism during pregnancy is characterized by ____ and ____
Maternal metabolism during pregnancy is characterized by mild fasting hypoglycemia and postprandial hyperglycemia
___ is the structural unit of each fetal cotyledon
Main stem villus is the structural unit of each fetal cotyledon
- Many cotyledons make up the placenta
- Main stem villus responsible for fetal circulation
Describe regulation of placental transfer
Regulation of placental transfer
- Mode of transport (e.g. simple diffusion vs active transport)
- Concentration of substance within maternal plasma: also dependent upon amount bound to carrier proteins
- Rate of maternal blood flow through intervillous space
- Rate of fetal blood flow
- Area available for exchange across villous trophoblast epithelium
- Amount of substance metabolized by placenta
- Area for exchange across fetal capillaries
Describe circulatory changes at birth
Circulatory changes at birth
- Alveolar expansion -> increased alveolar capillary O2 -> induces marked decrease in pulmonary vascular resistance -> decreased RA pressure and RV afterload
- Backflow of oxygenated blood into ductus arteriosus -> alters ductal production of prostaglandins -> localized vasoconstriction -> closure of ductus arteriorosus
- Closure of foramen ovale
- Collapse of ductus venosus and umbilical vessels
Describe fetal respiratory physiology
Fetal respiratory physiology
- Fetal breathing movements begin at age 16-22 weeks
Anatomical maturation
- Pseudoglandular stage (5-16 weeks)
- Canalicular stage (16-25 weeks)
- Terminal sac / alveolar stage (25 weeks - 8 years of life)
Describe fetal GI and renal / GU physiology
Fetal GI and renal / GU physiology
- GI: swallowing begins at 10-12 weeks
- Renal / GU: fetal kidneys produce urine and accounts for majority of amniotic fluid volume after 16 weeks
Fetal hemoglobin has ____ affinity for oxygen
Fetal hemoglobin has greater affinity for oxygen
Describe fetal endocrine physiology
Fetal endocrine physiology
- Thyroid hormones critical for normal development
- Fetal thyroid begins synthesizing thyroid hormone at 10-12 weeks
- Fetus dependent on maternal thyroid prior to this time
Describe fetal adrenal physiology
Fetal adrenal physiology
- Fetal adrenals at term weigh as much as adult adrenals (large fetal zone)
- Fetal adrenals account for a large amount of pregnancy steroidogenesis: precursor is cholesterol (maternal LDL)
Mechanisms resulting in parturition (childbirth) are ____ and ____
Mechanisms resulting in parturition (childbirth) are CRH and myometrial contractility
Describe stages of labor
Stages of labor
- Stage 1: interval between onset of labor and full cervical dilation: latent phase and active phase
- Stage 2: interval between full cervical dilation and delivery of fetus
- Stage 3: interval between delivery of neonate to delivery of placenta
