Common Pathologies of Pregnancy Flashcards
Describe the hormone levels in a normal ovarian cycle.
- Oestrogen peaks about day 14
- Progesterone rapidly increases from day 14 and decreases again by day 28 if pregnancy is not achieved
What happens to progesterone when a woman becomes pregnant?
Continues to increase beyond day 28
What does progesterone do once an egg has been fertilised?
Acts on the endometrium
- Thickens the lining
- Converts the endometrium to decidua
- Increases the vascularity of the endometrium
- Stromal cells enlarge between glands and vessels and become procoagulant which stops bleeding and leads to cessation of menstrual periods
What cells are found on the outer edge of the chorion?
Trophoblast cells
What do trophoblast cells produce?
Beta- human chorionic gonadotrophin
What is the target for B-hCG?
The corpus luteum of the ovary
What is the function of B-hCG?
To stimulate corpus luteum to produce progesterone, which stops decidua from shedding
What hormone forms the basis of pregnancy tests?
B-hCG
Describe the process of implantation.
- Chorion burrows into decidua
- Trophoblast cells stream off to invade mother’s blood vessels and link them up with the foetus
- Chorionic villi covered in trophoblasts move into the decidua
- Deceidual cells are procoagulant and help stop bleeding
- Eventually the chorionic villi are bathed in mother’s blood forming the forerunner of the placenta
What is an ectopic pregnancy?
Pregnancy which occurs in the wrong anatomical site
What is the most common site of ectopic pregnancy?
Fallopian tube
What predisposes to rupture in ectopic pregnancy?
Lack of proper decidual layer and small size of fallopian tube
What happens in normal pregnancy to promote growth of the baby and the placenta?
- Mum switches off certain genes in her eggs by methylating them
- Dad switches off certain genes in his sperm by methylating them
- Mum and dad’s changes lead to different genes being switched off
- Mum’s changes promote early baby growth
- Dad’s changes promote early placenta growth via trophoblast prooliferation
What is the pathogenesis behind a molar pregnancy?
- It is often caused by 2 sperm fertilising 1 egg with no chromosomes
- Results in imbalance of methylated genes causing trophoblast overgrowth
- Leads to no or all but non-existent foetal growth
What can happen if a molar pregnancy persists?
- Form of pre-cancer of trophoblast cells
- Can give rise to a malignant tumour called a choriocarcinoma
How is a molar pregnancy treated?
Removal of pregnancy
- If BhCG returns to normal then no further treatment is required
- If BhCG stays high (persistent disease) then cure with methotrexate
What are the associated problems of diabetes in pregnancy?
- Malformations
- Huge babies that obstruct labour
- IUD (probable sudden metabolic and hypoxic problems)
- Neonatal hypoglycaemia
What should those with diabetes do before becoming pregnant?
Obtain good glucose control before conception (to prevent malformations) and then all the way through pregnancy (to prevent metabolic complications)
Why do women with diabetes tend to have macrosomic babies?
- Effects of too much glucose in the mother
- Glucose crosses the placenta and raises babies blood glucose
- Insulin goes up in the baby
- Baby cannot reduce glucose as mum keeps sending more across the placenta
- Long-term high insulin and high glucose leads to massive growth
What can ascending infection in the mother cause ?
Ascending infection in mother such as acute chorioamnionitis can affect baby’s brain leading to conditions such as cerebral palsy in later life or even IUD
How does chorioamnionitis lead to neurological damage in the foetus?
- Mum’s neutrophils produce a cytokine storm.
- This activates some brain cells which then get damaged by normal hypoxia of labour
Do opiates cross the placenta?
Yes and baby can get addicted to them
How do opiate addicted babies usually do?
Pregnancy often goes well if mother is eating properly
How is an heroin addicted baby treated once it is born?
- Immediate withdrawal from heroin when the baby is born
- Later withdrawal from methadone
What is a placental abruption?
Separation of the placenta from the uterine wall
What effect does placental abruption have on the baby?
-Decreases baby’s supply of oxygen and results in hypoxia
What can placental abruption often cause in the mother?
Antepartum haemorrhage
How can varying degrees of bleeding occur as a result of placental abruption?
Placenta may separate in different places which can result in different degrees of bleeding
- Vaginal bleeding
- Formation of localised haematoma
What can cause placental abruption?
- Hypertension
- Trauma (including abuse)
- Other including cocaine use
Give some causes of miscarriage.
- Chromosomal abnormality
- Infection
- Maternal issues such as ill-health, trauma or hormonal problems
How can chorioamnionitis present in the mother?
- Mother can be ill with fever and raised neutrophils in the blood
- Mother be well
How can chorioaminionitis present in the baby?
- IUD
- Illness in the 1st days of life leading to NICU stay
- Cerebral palsy later in life
What are the typical organisms involved in chorioamnionitis?
Perineal or perianal flora including E.coli
What is over twisted cord a common cause of?
IUD and neonatal illness
