BIOM1060 Lecture Notes - Lecture 30: Genitourinary System, Chemotherapy, Down Syndrome
BIOM1060 24/04/18
EMBRYOLOGY PHYSIOLOGY
Normal symptoms of pregnancy
- Tiredness (due to increased progesterone)
- Nausea and vomiting (from 3 weeks)
- Possible small amount of bleeding at next expected menstrual period (due to small blood
loss at time of implantation)
- Breast tenderness
- Food cravings
- Chadwick’s sign: purplish hue of vagina
Calculating gestational age
- Gestational age: length of time since last period
- Embryonic age: time since fertilisation (about 14 days shorter)
oDifference between each increased if soon after using contraceptives
- Ultrasound assessment: crown rump length measured and fitted to population curve (1-4
day accuracy)
Normal early embryonic loss
- Estimated over 70% fertilised embryos lost before birth (many lost before first period)
- Embryonic period: period with most rapid rate of pregnancy loss
- Only sign of early embryonic loss may be slightly delayed menstrual period
- Due to insufficient progesterone/estrogen levels produced by corpus luteum or
chromosomal abnormalities
oSome embryos with inherent genetic abnormalities can continue to develop
Implantation and ectopic pregnancies
- Embryo only develops if implanted appropriately and in right location
- Ectopic pregnancy: embryo implants outside of uterus (eg. fallopian tube)
oProduce -human chorionic gonadotropin at slower rate than normal pregnancies
oRisk: tubular pregnancy may rupture uterine tube, can be life threatening (can be
treated pharmacologically or surgically)
oSymptoms: abdominal pain and abnormal bleeding
Poor implantation
- Inappropriate invasion = problems with placenta
(normal placenta positioning = decidua)
oPlacental accreta, increta and percreta: too
much invasion of placenta
oPlacenta praevia: blocks opening to cervix
- Insufficient implantation = placental abruption
(placenta separates early) or insufficient nutrient
uptake (preterm birth or foetal growth restriction)
- Inappropriate vascular remodelling = ischemic
reperfusions of placenta (preeclampsia)
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Document Summary
Possible small amount of bleeding at next expected menstrual period (due to small blood loss at time of implantation) Gestational age: length of time since last period. Embryonic age: time since fertilisation (about 14 days shorter: difference between each increased if soon after using contraceptives. Ultrasound assessment: crown rump length measured and fitted to population curve (1-4 day accuracy) Estimated over 70% fertilised embryos lost before birth (many lost before first period) Embryonic period: period with most rapid rate of pregnancy loss. Only sign of early embryonic loss may be slightly delayed menstrual period. Due to insufficient progesterone/estrogen levels produced by corpus luteum or chromosomal abnormalities: some embryos with inherent genetic abnormalities can continue to develop. Embryo only develops if implanted appropriately and in right location. Inappropriate invasion = problems with placenta (normal placenta positioning = decidua: placental accreta, increta and percreta: too much invasion of placenta, placenta praevia: blocks opening to cervix.
