Pregnancy and Maternal Adaptation (Lec 15) Flashcards
Pregnancy Tests
Measure Human Chorionic Gonadotropin (hCG) in urine or blood
Obstetrician
Specialises in care of pregnant women and the developing fetus
Gynecologist
Specialises in care of female reproductive system
Stages of Pregnancy
1st Trimester (Months 1-3): Initial development and rapid growth
2nd Trimester (Months 4-6): Continual fetus formation and development
3rd Trimester (Months 7-9): Growth
Stages of Pregnancy: 1st Trimester
(Months 1-3) Initial Development and Rapid Growth
- Organogenesis (heartbeat, 2-lobed brain, spinal cord
- Arms and legs with fingers, ears, toes
Stages of Pregnancy: 2nd Trimester
(Months 4-6) Continuation of Fetus Formation:
- Nails, eyebrows, eyelashes present
- Fetal movement felt by mothers
- Teeth, lips and possibly head hair
Stages of Pregnancy: 3rd Trimester
(Months 7-9) Growth:
- Eyes usually gray
- Fetus growth slows and moves into a head-down position
Maternal Adaptations to Pregnancy: Anatomical Changes
- Reproductive organs engorged with blood (Chadwick’s sign, areolae darken)
- Uterus expands
- Lordosis occurs with change in central grav.
- Relaxin hormone released = causes pelvic ligaments and pubic symphysis to relax
Maternal Adaptations to Pregnancy: Metabolic Changes
- Human placental lactogen (hPL) released which stimulates maturation of breasts, fetal growth, and glucose sparing in mother
- Parathyroid hormone and Vitamin D levels remain high during pregnancy to ensure calcium for fetal bone mineralization
- Increased appetite and energy requirements
Maternal Adaptations to Pregnancy: Physiological Changes
- Morning sickness
- Increased urine production due to increased maternal metabolism and fetal wastes
- Frequent, urgent urination and incontinence as bladder is compressed
- Estrogens may cause nasal edema
- Blood volume rises to safeguard against blood loss during childbirth
Purposes of Hormones in Pregnancy
- Maintain pregnancy
- Prepare for delivery
- Prepare for breastfeeding
3 Vascular Shunts
- Ductus Venosus: Umbilical vein drains into ductus venosus which empties into inferior vena cava (bypasses liver)
- Foramen Ovale: opening in interatrial septum bypasses pulmonary circulation
- Ductus Arteriosus: Pulmonary trunk drains into ductus arteriosus which drains into aorta (bypasses pulmonary circulation)
Fetal Circulation
- Oxygenated blood from umbilical vein
- Ductus venosus bypasses liver and delivers to inferior vena cava
- Oxygenated blood enters right atrium
- Foramen ovale allows passage from right atrium to left ventricle
- Ductus arteriosus connects aorta to pulmonary artery to bypass lungs
- Blood flows into left ventricle and pumped into aorta and into the body
- Some moves to umbilical arteries and re-enters the placenta (metabolic wastes)
Post-Birth Circulation
When infant breathes for first time:
- Decrease in pulmonary vasculature resistance
- Pressure equalises between atriums
- Results in closure of foramen ovale, ductus venosus and ductus arteriosus
Placental Hormones
Steroid hormones: Estrogens and Progesterone
Peptide Hormones: Human chorionic gonadotrophin (hCG), Human placental lactogen (hPL) and others
Prostaglandins
Placental Hormones: hCG
Maintains corpus luteum
Placental Hormones: Progesterone
Maintains uterine lining, inhibits uterine contraction
Placental Hormones: Estrogen
Maintains uterine lining, stimulates mammary glands
Placental Hormones: hPL
Stimulates mammary glands, supplies energy to fetus
Placental Hormones: Parathyroid Hormone related-protein (rp)
Increases blood calcium
Placental Hormones: Relaxin
Softens cervix and weakens pubic symphysis
Placental Hormones: Corticotropin Releasing-hormone
Increases heart rate, blood pressure, blood glucose, and stimulates partuition
Twin Pregnancies
Frequency ~3:100
Monozygotic Twins
Identical Twins
- Develop from a single zygote
- Have same chromosomes and will always be same sex
Dizygotic Twins
Fraternal Twins
- Develop from 2 fertilized ova
- Have different chromosomes, can be same or opposite sex
- Develop in seperate amniotic sacs and have seperate umbilical cords and placentas
Ultrasound (Sonogram)
High frequency sound waves used to image the developing baby. Can detect:
- sex, fetal heartbeat, anatomical abnormalities
- estimate due date
- check multiple pregnancies
Amnioscentesis
Amniotic fluid surrounding fetus is removed using a fine needle inserted through abdomen and examined. Used to assess:
- fetal cells and other substances in fluid
- birth defects and diseases
- sex
Chorionic Villus Sampling Test (CVS Test)
Done during early pregnancy where biopsy is taken of the villi in the placenta
- Trans-cervical procedure
- Trans-abdominal procedure
Gestational Diabetes Mellitus
Abnormally raised blood sugar levels after hormones from placenta cause cells to become insulin resistant. Affects mother, not child
Preeclampsia
Deterioration of placenta and insufficient placental blood supply which can leads to fetus being starved of oxygen. Marked by:
- high blood pressure
- failing kidneys
- swelling in hands, feet, legs
- protein in the urine
Supplements during Pregnancy: Folate and Folic Acid
Proven to be particularly important for the development of the nervous system and for preventing neural tube defects
Supplements during Pregnancy: Iron
Iron is critical for oxygen transport, healthy growth and development of the fetus and placenta.
Supplements during Pregnancy: Vitamin D
Important for immune function, bone health and cell division
