Disorders Of Early Fetal Development Flashcards
What are the (3) causes of pregnancy loss
- Errors in embryo-fetal development
- Failure of the embryo to implant in the uterine lining
- Inability to sustain development of an implanted embryo/fetus
Recurrent miscarriage
Three or more pregnancy losses
Major cause of early clinical pregnancy loss
Aneuploidy in embryo
Why does increasing maternal age increase risk of miscarriage
Loss of cohesion between homologous chromosomes in oocyte due to cohesins degrading as you get older
Thus chromatids separate and drift rather than segregate accurately by spindle
2 cohesion proteins
REC8 and SMC2
Meiotic arrest
Occurs as oocyte is waiting for entry of sperm
Prophase of fist meiotic division
When is meiosis resumed after meiotic arrest
Before ovulation
Ectopic pregnancy
Implantation if the embryo at a site other than the uterine endometrium
How are ectopic pregnancies treated
Chemotherapy
Surgery to remove affected tube
What can rupture of fallopian tubes lead to
Severe internal bleeding
Adaptations of falopian tubes
Smooth muscle contraction which facilitate movement of embryo along uterine wall
Epithelium coated in cilia to promote fluid movement
How does maternal smoking increase ectopic pregnancy
Continine regulates expression of PROKR1 which causes smooth muscle to contract,it inhibits this causing transition failure
Increases expression of pro apoptotic proteins in fallopian tube explants
Tobacco inhibits ciliary function reducing embryo transition
Cannabis affect
Fallopian tube expresses CB1 and CB2 cannabinoid
CB1 reduced in ectopic pregnancy patients
THC in cannabis may directly act on fallopian tube to disturb or alter balance of endocannabinoids leading to disrupted embryo environment
Risk factors for ectopic pregnancy
Cannabis use
Smoking
Prior ectopic pregnancy
Prior fallopian tube surgery
Certain STIS
Pelvic inflammatory disease
Endometriosis
Infertility history
Ivf
Age >35
