Physiology Of Pregnancy Flashcards
How long is the Average Human Pregancy?
40 weeks - (9 months)
How many trimesters in pregnancy?
-
Three Trimesters
- first (<12 weeks)
- second (12 weeks to end week 26)
- third (27 weeks – birth)
When is the First Trimester? (Pregancy)
first (<12 weeks)
When is the Second Trimester? (Pregancy)
second (12 weeks to end week 26)
When is the Third Trimester? (Pregancy)
third (27 weeks – birth)
During Pregnancy, there are many … changes – ie. not … changes - that take place to support the to support the needs of a … …
- During Pregnancy, there are many physiological changes – ie. not pathological changes - that take place to support the to support the needs of a growing fetus
- Supplying a baby with enough nutrients (O2, glucose, amino acids) for growth, development, production of amniotic fluid
- Managing increased waste production – eg. CO2, nitrogen compounds
- Change in hormones to support pregnancy and prepare
- for delivery
- Anatomical changes to accommodate the growing fetus and
- preparing for labour
- Manage the stresses of delivery and potential haemorrhage
- Postnatal Recovery and Breastfeeding
Physiological Changes During Pregnancy:
- Supplying a baby with enough … (O2, glucose, amino acids) for growth, development, production of … fluid
- Managing increased … production – eg. CO2, nitrogen compounds
- Change in … to support pregnancy and prepare
- for delivery
- … changes to accommodate the growing fetus and
- preparing for labour
- Manage the … of delivery and potential …
- … Recovery and B…
- Supplying a baby with enough nutrients (O2, glucose, amino acids) for growth, development, production of amniotic fluid
- Managing increased waste production – eg. CO2, nitrogen compounds
- Change in hormones to support pregnancy and prepare
- for delivery
- Anatomical changes to accommodate the growing fetus and
- preparing for labour
- Manage the stresses of delivery and potential haemorrhage
- Postnatal Recovery and Breastfeeding
Which systems undergo some form of change during Pregnancy?
- All of them!!
- Endocrine
- Cardiovascular
- Respiratory
- Haematocological
- Musculoskeletal/Dermatological
Endocrine Changes During Pregnancy
- 3 MAIN HORMONES INVOLVED IN PREGNANCY that you need to know about
- … – dramatic rise in the first days-weeks - released from the corpus luteum initially, then by placenta
- … - keeps the state of quiescence
- … – breast growth, areolar enlargement
- Other hormone changes include …, … and …
- 3 MAIN HORMONES INVOLVED IN PREGNANCY that you need to know about
- BHCG – dramatic rise in the first days-weeks - released from the corpus luteum initially, then by placenta
- Pro-gest-erone eg.pro-gestation - keeps the state of quiescence
- Oestrogen – breast growth, areolar enlargement
- Other hormone changes include relaxin, inhibin and TSH

BHCG and Pregnancy
- When is there a dramatic rise?
- Released by … initially, then by …
- Dramatic rise in the first days-weeks
- released from the corpus luteum initially, then by placenta

Progesterone and Pregnancy
- Keeps the state of …
- Keeps the state of quiescence

Oestrogen and Pregnancy
- Growth of … and enlargement of …
- breast growth, areolar enlargement

HCG & Pregnancy - Clinical Picture
- Maintains corpus luteum secretion of prog & oest, … as the placental production of progesterone increases
- … unit forms the basis of pregnancy testing.
- … unit can mimic LH, FSH, and TSH
- Large quantities are released in … pregnancy and … pregnancy
- High levels cause … (hyper…)
- Maintains corpus luteum secretion of prog & oest, decreases as the placental production of progesterone increases
- beta unit forms the basis of pregnancy testing.
- Alpha unit can mimic LH, FSH, and TSH
- Large quantities are released in molar pregnancy and multiple pregnancy
- High levels cause vomiting (hyperemesis)
Progesterone & Pregnancy - Clinical Picture
- Progesterone relaxes … … – everywhere!
- Maintains uterine … by … uterine electrical activity
- Constipation, … reflux, supra-… dysfunction
- … suppressor ( HLA )
- Lobulo-alveolar development in …
- Substrate for fetal adrenal corticoid synthesis eg. …
- Progesterone relaxes smooth muscle – everywhere!
- Maintains uterine quiescence by decreasing uterine electrical activity
- Constipation, gastric reflux, supra-pubic dysfunction
- Immune suppressor ( HLA )
- Lobulo-alveolar development in breasts
- Substrate for fetal adrenal corticoid synthesis eg cortisol
Oestrogen & Pregnancy - Clinical Picture
- Growth of the …, … changes
- Development of … system of breasts
- Stimulation of … synthesis
- Growth of the uterus, cervical changes
- Development of ductal system of breasts
- Stimulation of prolactin synthesis
The Placenta as an Endocrine Organ
- Protein hormones:
- hCG (human chorionic gonadotrophin) – produced by trophoblast, first detectable 8-9 days, peaks 8-9 weeks.
- hPL (human placental lactogen) - Similar structure to prolactin and growth hormone. Larger placenta produces … hPL. Alters maternal carbohydrate and lipid … to provide steady state of glucose for fetal requirements
- hPG (human placental gonadotrophin) induces maternal … resistance to regulate fetal … – this may become a pathological process seen as GDM
- CRH (corticotropin releasing hormone)
- Steroids:
- …
- … (oestriol)
- Protein hormones:
- hCG (human chorionic gonadotrophin) – produced by trophoblast, first detectable 8-9 days, peaks 8-9 weeks.
- hPL (human placental lactogen) - Similar structure to prolactin and growth hormone. Larger placenta produces more hPL. Alters maternal carbohydrate and lipid metabolism to provide steady state of glucose for fetal requirements
- hPG (human placental gonadotrophin) induces maternal insulin resistance to regulate fetal growth – this may become a pathological process seen as GDM
- CRH (corticotropin releasing hormone)
- Steroids:
- Progesterone
- Oestrogen (oestriol)
During Pregnancy, there is a …% increase in plasma volume
During Pregnancy, there is a 40% increase in plasma volume - 2.5L to 3.7L (8-10kg gain)
During Pregnancy, there is a …% increase in RBC, leading to …
During Pregnancy, there is a 25% increase in RBC, leading to dilutional anaemia

During Pregnancy, Plasma colloid osmotic pressure …
During Pregnancy, Plasma colloid osmotic pressure falls - shift of fluid into extracellular space
During Pregnancy, there is an … in clotting factors - … state
During Pregnancy, there is an increase in clotting factors - hypercoaguable state
- evolutionary balance between thrombosis and haemorrhage
- Increasine plasma fibrinogen (increased ESR), platelets, factor VIII, and von willebrand factor

Cardiovascular System and Pregnancy
- Increased blood volume has implications on:
- cardiac output (…) increase or decrease?
- peripheral resistance (…) increase or decrease?
- … pressure
- Heart is working hard reach supply demands of the fetus – increase in heart rate and stroke volume to account for …
- Remember C.O. = … x …
- Heart enlarges by ….% (increased venous return)
- Innocent … murmurs are common (~90%)
- Beware … murmur – may signify cardio…
- Increased blood volume has implications on:
- cardiac output (increased)
- peripheral resistance (decreased)
- blood pressure (slightly lower)
- Heart is working hard reach supply demands of the fetus – increase in heart rate and stroke volume to account for increase in cardiac output
- Remember C.O. = Stroke volume x Heart Rate
- Heart enlarges by 12% (increased venous return)
- Innocent systolic murmurs are common (~90%)
- Beware diastolic murmur – may signify cardiomyopathy
During Pregnancy, the heart is working heard to reach supply demands of the fetus. The heart enlarges by …%
During Pregnancy, the heart is working heard to reach supply demands of the fetus. The heart enlarges by 12%
Innocent … murmurs are common during pregnancy
Innocent systolic murmurs are common during pregnancy (approx 90%)
Beware … murmurs during pregnancy - may signify cardiomyopathy
Beware diastolic murmurs during pregnancy - may signify cardiomyopathy
Peripheral Vascular Resistance - Pregnancy
- Peripheral vasodilatation (effect of …)
- Peripheral resistance decreases by …%
- Combined with … cardiac output, results in slightly … BP
- Decreased vascular resistance leads to … blood pressure
- Peripheral vasodilatation (effect of progesterone)
- Peripheral resistance decreases by 35%
- Combined with increased cardiac output, results in slightly lower BP
- Decreased vascular resistance leads to lower blood pressure

Pregnancy and CVS overview

Respiratory System - Non-pregnant

Respiratory System and Pregnancy
- Increased … demands
- Decrease maternal p… & increase maternal p…
- Increased availability of O2 to tissues and aids passive diffusion at the …, HbF … oxygen affinity
- Increased oxygen demands!
- Decrease maternal pCO2 & increase maternal pO2
- Increased availability of O2 to tissues and aids passive diffusion at the placenta, HbF higher oxygen affinity

Respiratory System and Pregnancy

Clinical Picture - Pregnancy & Respiratory and Cardiovascular System
- Splinting of diaphrgm, increased ventilation – sensation of increasing …
- Raised HR leads to …
- Lots of cross over with symptoms for … and known hypercoagulable state… leads to lots of investigations…!
- Excess plasma volume shifts causing … – peripheral
- Decreased … tolerance
- Low BP causing … / …
- Splinting of diaphrgm, increased ventilation – sensation of increasing SOB
- Raised HR leads to palpitations
- Lots of cross over with symptoms for PE and known hypercoagulable state… leads to lots of investigations…!
- Excess plasma volume shifts causing oedema – peripheral
- Decreased exercise tolerance
- Low BP causing fainting / dizziness
Musculo-skeletal / Dermatological Changes in Pregnancy
- Increased lumbar …
- Ligamentous … – pelvic girdle pain / pubis dysfunction
- … marks
- Changes in skin … - Linea Nigra, melasma, darkened nipples
- … Tunnel
- S…
- Cr..
- Increased lumbar lordosis - Lordosis is the inward curve of the lumbar spine (just above the buttocks)
- Ligamentous laxity – pelvic girdle pain / pubis dysfunction
- Stretch marks
- Changes in skin pigmentation - Linea Nigra, melasma, darkened nipples
- Carpal Tunnel
- Sciatica
- Cramps

What is Sciatica?
Sciatica is where the sciatic nerve, which runs from your lower back to your feet, is irritated or compressed
Breast Changes in Pregnancy
- oestrogen increases … tissue – enlargement and areolar enlargements and the ductal system
- Progesterone enlarges breast …
- oestrogen increases adipose tissue – enlargement and areolar enlargements and the ductal system
- Progesterone enlarges breast lobules
Urological Changes in Pregnancy
- Kidney increases …cm in size during normal pregnancy
- increased renal flow by …%
- increased … (BUT tubular reabsorption capacity is unchanged) - decreased glucose reabsorption - glycosuria is common
- Plasma levels of creatinine and urea … in pregnancy
- … ureters (progesterone)
- Increased … (increased urine …)
- Kidney increases 1cm in size during normal pregnancy
- increased renal flow by 50%
- increased GFR (BUT tubular reabsorption capacity is unchanged) - decreased glucose reabsorption - glycosuria is common
- Plasma levels of creatinine and urea decrease in pregnancy
- Dilated ureters (progesterone)
- Increased pressure (increased urine frequency)
Kidney increases …cm in size during normal pregnancy
Kidney increases 1cm in size during normal pregnancy
In pregnancy, increased renal flow by …%
In pregnancy, increased renal flow by 50%
Thyroid Changes in Pregnancy
- … serum T3 & T4 levels, … in thyroid binding globulin (oestrogen)
- As only unbound T3 and T4 is active, levels of free T3 and T4 …. or … slightly
- Increased serum T3 & T4 levels, Increase in thyroid binding globulin (oestrogen)
- As only unbound T3 and T4 is active, levels of free T3 and T4 remain the same or fall slightly
Physiological Changes during Pregnancy - System Overview
