SM_208b: Normal Pregnancy

Question 1

Describe physiological changes in the uterus during pregnancy

Answer 1

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

Question 2

Describe physiological changes in the cervix / vagina during pregnancy

Answer 2

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

Question 3

Chadwick sign is ____

Answer 3

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

Question 4

Describe physiological changes in the ovaries during pregnancy

Answer 4

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%

Question 5

Theca lutein cysts in the ovaries are ____, ____, and ____

Answer 5

Theca lutein cysts in the ovaries are associated with high hCG levels, bilateral cystic ovaries, and maternal virilization occurs in 25%

Question 6

Decidual reaction in ovaries is ____

Answer 6

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

Question 7

In pregnancy, cardiovascular changes include ____, ____, and ____

Answer 7

In pregnancy, cardiovascular changes include enlarged cardiac silhouette due to elevation of diaphragm, increase in HR, and increase in CO

Question 8

MAP is lowest in ____ of pregnancy

Answer 8

MAP is lowest in middle of pregnancy

Question 9

In pregnancy, elevation of diaphragm ____ respiratory function

Answer 9

In pregnancy, elevation of diaphragm changes respiratory function

Question 10

Describe maternal GI tract physiology in pregnancy

Answer 10

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

Question 11

Describe maternal hepatic physiology during pregnancy

Answer 11

Maternal hepatic physiology during pregnancy

• Increased hepatic blood flow
• Labs: D-dimer increases, alk phos increases, albumin decreases
• Anatomic changes: appendix location

Question 12

Pregnancy effect on hepatic labs

• D-dimer: ____
• Alk phos: ____
• Albumin: ____

Answer 12

Pregnancy effect on hepatic labs

• D-dimer: increases
• Alk phos: increases
• Albumin: decreases

Question 13

Describe maternal renal / urinary physiology during pregnancy

Answer 13

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

Question 14

Maternal blood volume ___ during pregnancy

Answer 14

Maternal blood volume increases during pregnancy

Question 15

Describe maternal hematologic physiology during pregnancy

Answer 15

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

Question 16

Pregnancy effect on coagulation labs

• Clotting factors (including fibrinogens): ____
• tPA: ____
• Protein S: ____
• Activated protein C: ____

Answer 16

Pregnancy effect on coagulation labs

• Clotting factors (including fibrinogens): increase (except factors XI and XIII)
• tPA: increase
• Protein S: decrease
• Activated protein C: decrease

Question 17

Most circulating hormones are ____ in pregnancy as a result of the fetus and placenta

Answer 17

Most circulating hormones are increased in pregnancy as a result of the fetus and placenta

Question 18

Describe maternal endocrine physiology during pregnancy

Answer 18

Maternal endocrine physiology during pregnancy

Question 19

Describe effect of pregnancy on thyroid hormone

Answer 19

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)

Question 20

Describe maternal metabolic physiology during pregnancy

Answer 20

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

Question 21

Maternal metabolism during pregnancy is characterized by ____ and ____

Answer 21

Maternal metabolism during pregnancy is characterized by mild fasting hypoglycemia and postprandial hyperglycemia

Question 22

___ is the structural unit of each fetal cotyledon

Answer 22

Main stem villus is the structural unit of each fetal cotyledon

• Many cotyledons make up the placenta
• Main stem villus responsible for fetal circulation

Question 23

Describe regulation of placental transfer

Answer 23

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

Question 24

Describe circulatory changes at birth

Answer 24

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

Question 25

Describe fetal respiratory physiology

Answer 25

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)

Question 26

Describe fetal GI and renal / GU physiology

Answer 26

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

Question 27

Fetal hemoglobin has ____ affinity for oxygen

Answer 27

Fetal hemoglobin has greater affinity for oxygen

Question 28

Describe fetal endocrine physiology

Answer 28

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

Question 29

Describe fetal adrenal physiology

Answer 29

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)

Question 30

Mechanisms resulting in parturition (childbirth) are ____ and \_\_\_\_

Answer 30

Mechanisms resulting in parturition (childbirth) are CRH and myometrial contractility

Question 31

Describe stages of labor

Answer 31

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