Implantation Flashcards
Where does fertilization normally occur?
Ampulla
Define decidualization
Decidualization = stromal changes in uterus to allow implantation
*Includes accumulation of glycogen and lipids
What cells make hCG?
What is its purpose?
Trophoblast cells
Maintains corpus luteum (and thus progesterone) for first 8-10 wks
What is hatching?
Hatching = blastocyst escaping the zona pellucida
(required for implantation)
What is it called when the placenta implants on top of the internal cervical os?
Placenta previa
What is morbidly adherent placenta and what is the underlying defect?
Excessive placental invasion into uterine wall due to a defective decidual layer
Where do ectopic pregnancies most commonly occur?
Ampulla
(same site as fertilization)
4 Risk factors for ectopic pregnancy
Tubal disease (PID)
prior ectopic pregnancy
infertility tx
smoking
What are two objective signs of ectopic pregnancy?
hCG rising abnormally
no intrauterine pregnancy visible
Medical tx for ectopic pregnancy
Methotrexate
When does a urine pregnancy test become positive?
4 weeks after last menses
How does progesterone affect
- Endometrium (2)
- Cervical mucous
- Body temp
- LH, FSH levels
- Myometrium
- Stimulates endometrial secretions and spiral artery development, prevents hyperplasia
- Makes thick cervical mucous
- Increases body temp
- Suppresses LH, FSH
- Uterine smooth muscle relaxation
What is one symptom of placenta previa?
Name 2 risk factors
Painless 3rd trimester bleeding
Multiparity, previous C-section
Distinguish placenta accreta, increta, and percreta
All forms of morbidly adherent placenta
- Accreta = placenta attaches without penetrating
- Increta = placenta penetrates into myometrium
- Percreta = placenta pentrates through myometrium into uterine serosa or other abdominal structures (perforates through)
What is the major risk factor for morbidly adherent placenta?
Previous uterine surgery/instrumentation
What is the major complication of placenta accreta?
Placenta does not separate after delivery -> postpartum hemorrhage
bHCG share the same subunit as what other 3 hormones?
What hormone does it mimic physiologically?
bHCG, TSH, LH, and FSH all share subunit
bHCG mimics LH physiologically
At what day/week does each occur?
- Morula
- Blastocyst
- Implantation
- Bilaminar disc
- Trilaminar disc
- Closure of neural tube
- Heart beat
- Limb buds
- Fetal movement
- Genitalia visible
- Morula: within 4 days
- Blastocyst: within 5 days
- Implantation: within 6 days (s**tick at six)
- Bilaminar disc: 2 weeks
- Trilaminar disc: 3 weeks (3 layers at 3 weeks)
- Closure of neural tube: 4 weeks
- Heart beat & limb buds: 4 weeks (4 chambers, 4 limbs)
- Fetal movement: 8 weeks (gait at eight)
- Genitalia visible: 10 weeks (TENitalia)
