Week+3+Normal+Pregnancy+%26+Tests+Slides
Normal Pregnancy & Tests
Focus on physiological changes and developmental milestones during pregnancy.
Human Development
Key developmental periods: Pre-embryonic, Embryonic, and Fetal periods.
The Menstrual Cycle
Phases:
Follicular Phase: Day 1 to ~Day 14
Hormones: FSH, LH, Estrogen, Progesterone
Temperature: Basal body temperature at 36.4°C to 36.7°C
Luteal Phase: ~Day 14 to 28
Ovulation: Released ovum
Pre-embryonic Period
Duration: First two weeks post-conception.
Important processes:
Fertilization to implantation.
Best implantation site: Upper uterus due to rich vascular supply.
Thick uterine lining prevents deep attachment of the placenta.
Embryonic Period
Duration: 3rd to 8th week post-conception.
Major developments:
Completion of basic structures and organ systems.
Teratogens pose a significant risk for damage during this period.
Growth Patterns: Cephalocaudal (head-to-toe) and central-to-peripheral.
Fetal Period
Duration: 9 weeks post-conception until delivery.
Focus on:
Rapid cell division, organ refinement.
Vulnerability of the central nervous system throughout pregnancy.
Normal Fetal Growth
12 weeks:
Length: 7-9 cm, Weight: 28 g.
16 weeks:
Length: 10-17 cm, Weight: 55-120 g.
20 weeks:
Length: 25 cm, Weight: 223 g.
28 weeks:
Length: 35-38 cm, Weight: 1,200 g.
32 weeks:
Length: 38-43 cm, Weight: 1,500-2,500 g.
36 weeks:
Length: 42-49 cm, Weight: 1,900-2,700 g.
40 weeks:
Length: 48-52 cm, Weight: 3,000 g.
Auxiliary Structures
Placenta:
Normal Pregnancy & Tests
Focus on physiological changes and developmental milestones during pregnancy.
Common Tests & Screenings:
First Trimester (Weeks 1-12):
Blood tests: Check blood type, Rh factor, anemia, infections (e.g., rubella, syphilis, hepatitis B, HIV).
Urine tests: Screen for UTIs, protein, glucose.
Ultrasound: Confirm pregnancy, estimate due date, check for multiple pregnancies, assess fetal heart rate and early development.
Nuchal Translucency (NT) scan: Assess risk for chromosomal abnormalities like Down syndrome.
Second Trimester (Weeks 13-28):
Ultrasound (Anomaly Scan/Level II): Detailed assessment of fetal anatomy, organ development, growth, and placental location (typically around weeks 18-22).
Maternal Serum Screening (Quad Screen): Blood test to assess risk for neural tube defects and chromosomal abnormalities.
Glucose Challenge Test (GCT): Screen for gestational diabetes (typically weeks 24-28).
Amniocentesis: Diagnostic procedure (if indicated) to detect chromosomal abnormalities or genetic conditions.
Third Trimester (Weeks 29-40):
Glucose Tolerance Test (GTT): Confirmatory test for gestational diabetes.
Group B Streptococcus (GBS) Screening: Swab test to detect GBS colonization (around weeks 35-37).
Cervical examination: Assess cervical dilation and effacement as pregnancy nears term.
Non-stress test (NST) or Biophysical Profile (BPP): Assess fetal well-being, movement, heart rate reactivity, and amniotic fluid volume (if concerns arise).
Human Development
Key developmental periods: Pre-embryonic, Embryonic, and Fetal periods.
The Menstrual Cycle
Phases:
Follicular Phase: Day 1 to ~Day 14
Hormones: FSH, LH, Estrogen, Progesterone
Temperature: Basal body temperature at to
Luteal Phase: ~Day 14 to 28
Ovulation: Released ovum
Pre-embryonic Period
Duration: First two weeks post-conception.
Important processes:
Fertilization to implantation.
Best implantation site: Upper uterus due to rich vascular supply.
Thick uterine lining prevents deep attachment of the placenta.
Embryonic Period
Duration: 3rd to 8th week post-conception.
Major developments:
Completion of basic structures and organ systems.
Teratogens pose a significant risk for damage during this period.
Growth Patterns: Cephalocaudal (head-to-toe) and central-to-peripheral.
Fetal Period
Duration: 9 weeks post-conception until delivery.
Focus on:
Rapid cell division, organ refinement.
Vulnerability of the central nervous system throughout pregnancy.
Normal Fetal Growth
12 weeks:
Length: 7-9 cm, Weight: 28 g.
16 weeks:
Length: 10-17 cm, Weight: 55-120 g.
20 weeks:
Length: 25 cm, Weight: 223 g.
28 weeks:
Length: 35-38 cm, Weight: 1,200 g.
32 weeks:
Length: 38-43 cm, Weight: 1,500-2,500 g.
36 weeks:
Length: 42-49 cm, Weight: 1,900-2,700 g.
40 weeks:
Length: 48-52 cm, Weight: 3,000 g.
Auxiliary Structures
Placenta:
Function: Transfers nutrients and oxygen from the mother to the fetus, removes waste products from the fetus, and produces hormones (e.g., hCG, progesterone, estrogen) essential for maintaining pregnancy.
Structure: Develops from both maternal (decidua basalis) and fetal (chorion frondosum) tissues. It is a highly vascularized organ.
Barrier: Acts as a selective barrier, allowing beneficial substances to pass through while largely blocking harmful ones, though some drugs, alcohol, and viruses can cross.
Umbilical Cord: Connects the fetus to the placenta.
Contains two umbilical arteries (carrying deoxygenated blood and waste from fetus to placenta) and one umbilical vein (carrying oxygenated blood and nutrients from placenta to fetus).
Wharton's Jelly: Protective connective tissue surrounding the vessels within the cord, preventing compression.
Amniotic Sac (Amnion and Chorion): The fluid-filled sac that surrounds and protects the fetus.
Amniotic Fluid: Cushions the fetus, allows for fetal movement, helps maintain a constant temperature, and contributes to fetal lung and gastrointestinal development.
Volume increases throughout pregnancy, peaking around 34-36 weeks.
Yolk Sac: Present in early pregnancy; provides nourishment to the embryo before the placenta is fully functional and plays a role in the development of the circulatory system and germ cells.