Complications & Pathologies of Pregnancy Flashcards
What is miscarriage defined as?
Spontaneous loss of pregnancy before 24 wks gestation (defined as the spontaneous loss of pregnancy before the fetus reaches viability. The term therefore includes all pregnancy losses from the time of conception until 24 weeks of gestation)
What is an abortion?
A voluntary termination of pregnancy
What is the incidence of spontaneous miscarriage?
15%
What is a threatened miscarriage?
Bleeding from gravid uterus before 24 wks gestation +/- pain & there is a viable foetus & no evidence of cervical dilation
What is inevitable miscarriage?
Cervix begun to dilate-open cervix with bleeding that could be heavy (+/-clots)
What is an incomplete miscarriage?
Only partial expulsion of the products of conception
What is a complete miscarriage?
When there is a complete expulsion of products
- Passed all products of conception (POC)
- Cervix closed & bleeding has stopped (should ideally have confirmed the POC or should have had a scan previously that confirmed an intrauterine pregnancy)
Define a septic miscarriage?
Ascending infection into uterus-can spread throughout pelvis
- Especially in cases of an incomplete miscarriage
What type of miscarriage is it when a foetus has died but the uterus has made no attempts to expel the products of conception?
Missed miscarriage
- No symptoms, or could have bleeding/brown loss vaginally
- Gestational sac seen on scan
What is a viable pregnancy?
“viable pregnancy” after 22-24 weeks is a pregnancy when there is a chance that if delivered the baby can survive
What is the role of the ovary?
Egg store & hormone release
What is the muscle of the uterus called?
Myometrium
What is the role of the cervix?
To keep canal narrow during pregnancy & dilates during labour to allow baby out- Also allows spermatozoa up but not bacteriato prevent infection
When progesterone keeps rising in the hormone cycle what does this indicate?
Egg is fertilised
What does progesterone (or progestogen) do to the endometrium?
Thickens the lining, changes cells
- Turns endometrium into decidua-increases vascularity (monthly shedding occurs here and is akin to falling of leaves from a decidual tree)
- Between glands & vessels the stromal cells enlarge & become procoagulant-stops bleeding
What is fertilised by sperm?
Egg (‘chorion’)
Outer edge of chorion=trophoblast cells on outside of the fertilised egg
Trophoblast cells produce which hormone?
B-hCG (Beta-human Chorionic Gonadotrophin)
What is the target for B-hCG?
Target is corpus luteum in the ovary
What is the function of B-hCG & what is it used for clinically?
Its function is to stimulate the corpus luteum to produce progestogen, which stops decidua from shedding
It forms the basis of pregnancy tests - Stimulates ovary to produce progesterone throughout pregnancy & stops decidua from shedding
Where does the fertilised egg burrow into?
Into the decidua
What are trophoblasts & what do the do?
Are placental cells that only exist in pregnancy. It is a fetal cell.
Invade mother’s blood vessels & eventually link these vessels up with those of the foetus
Where are decidual stromal cells located & what is their purpose?
Between vessels (of mother) - they are procoagulant & stop trophoblast cells causing too much bleeding when they invade mothers blood vessels
Fill in the blanks: Projections of chorion (chorionic ..(1)…) covered in ..(2).. cells start to move into the decidua. Eventually the chorionic …(1)… are bathed in the mother’s blood forming the forerunner of the …(3)….
1) Villi
2) Trophoblast
3) Placenta
Why does B-hCG return to normal (ie zero)?
No trophoblasts left in mother
Why do miscarriages happen (causes)?
- Unknown (it is very common for no cause to be obvious)
Causes include:
1. Fetal problem eg chromosomal abnormality,
2. Placenta/membranes/cord problem eg infection,
3. Uterus/cervix problem (eg cervical incompetence)
4. Maternal health issues (eg drug taking)
What is an ectopic pregnancy & where is the most common site of it?
Pregnancy in the wrong anatomical site
Most common site is in the fallopian tube (lack of proper decidual layer & small size of tube predispose to haemorrhage & rupture)
If presents early woman may not even know she is pregnant
What is a molar pregnancy?
Form of PRE cancer of trophoblast cells- enlarged abnormal chorionic villi with abundant trophoblast
What can occur if a molar pregnancy persists?
Can rarely give rise to a malignant tumour called CHORIOCARCINOMA
What are the causes of molar pregnancy?
- Normal ovary-certain genes are switched off in ova by methylating them
- Normal testis-different genes are switched off in sperm by methylating them
- Mums changes promote early baby growth & dad’s changes promote early placenta growth via trophoblast proliferation-overall effect is balanced growth of baby & placenta
Molar pregnancy has various causes but can be caused by 2 sperm fertilising one egg with NO chromosomes - Result is imbalance in methylated genes - trophoblast cells proliferate
A problem because in the testis dad has inactivated several genes by adding methyl groups to stretches of DNA –massive overgrowth of trophoblast cells and therefore overgrowth of placenta – no or all but non-existent fetal growth
How is molar pregnancy treated post surgical removal?
If BhCG returns to normal – no further treatment.
If BhCG stays high (persistent disease) - cure by methotrexate
Why can babies be so big in those with DM (uncontrolled)?
Effects of too much Glc in mother
Why can babies be so big in those with DM (uncontrolled)?
Effects of too much Glc in mother (there is decreased maternal insulin)
Does Glc cross the placenta?
YES, so insulin goes up in baby - baby CANNOT reduce Glc so mum keeps sending more across the placenta
In a baby what does longterm high insulin & high Glc cause?
Massive growth-susceptibility to IUD
What are the problems encountered with diabetes in pregnancy?
1st trimester: Malformations
3rd trimester: Intrauterine death (probable sudden metabolic and hypoxic problems)
Labour: Huge babies that obstruct labour
Neonatal period: hypoglycaemia
Why is good Glc control in diabetes needed BEFORE conception?
To prevent malformations - and then is needed all the way through to prevent metabolic complications
What is acute chorioamnionitis?
Neutrophils present in membranes (chorioamnionitis), cord & fetal plate of placenta–acute inflammation
Ascending infection-bacteria are typically perineal or perianal flora (e.g. E.coli) which ascend vagina & get into the amniotic sac
Presentation:
Mother has fever & raised neutrophils BUT mother can be well!
Baby=IUD, Ill in 1st days of life (neonatal unit) or cerebral palsy later on in life
How does ascending infection affect the babys brain?
Neutrophils produce cytokine ‘storm’. This activates some brain cells, which then get damaged by normal hypoxia of labour.
Do opiates cross the placenta?
YES
IVDU that become pregnant are prebooked to deliver beside neonatal unit. WHY?
So baby can be admitted to neonatal unit & treated for heroin withdrawal for example
Pregnancy often proceeds well if mother eating properly
Immediate withdrawal from heroin when baby is born-later withdrawal from methadone
What is an overtwisted cord a common cause of ?
IUD & neonatal illness
Problem is caused by a normal, active baby moving & twisting round its own cord
What is APGAR?
Appearance, Pulse, Grimace, Activity and Respiration
What is placental abruption?
Separation of placenta from uterine wall-results in hypoxia in baby
Can get both a haematoma & bleeding per vagina
Often causes APH in mother
What are the causes of placenta abruption?
- HT
- Trauma
- Other - e.g. Cocaine
What is the most common cause of heavy painless vaginal bleeding?
PLACENTA PRAEVIA
- Most common in multiparous women, multiple pregnancies & those with previous CS
What symptoms is abruption likely to come with?
Pain or at least a tender, firm abdomen
Apart from placenta praevia & placental abruption what are some other causes of APH?
Placenta accreta, vasa praevia, local lesions of genital tract etc.
Once these are ruled out may consider a cancer (ask about last smear test)
How is placenta praevia diagnosed?
USS
Transvaginal may be required to provide accurate measurement of how placenta is related to the cervix
This is safe to do, but vaginal exam is not safe as may exacerbate haemorrhage
How does major (grades III & IV) differ from minor (grades I & II) placenta praevia?
Grade IV => centre of placenta over cervical os
Grade I => placenta in lower uterine segment, but not close to os
How is placenta praevia managed?
ABCDE approach
IV access, cross match and transfusion if shocked
Foetal monitoring CTG
US if diagnosis in doubt and patient stable
Maternal monitoring HR, BP, temp.
Steroids if preterm delivery likely - IV betamethasone
Magnesium sulphate if preterm delivery imminent
Anti-D if rhesus negative
What are some complications of placenta praevia?
- Premature delivery
- PPH
- Hysterectomy
- Blood loss
Onset of labour before how many weeks is defines as ‘preterm’?
37 completed weeks gestation
32-36 weeks mildly preterm
28-32 weeks very preterm
24-28 weeks extremely preterm
What is labour defined as?
Onset of contractions with progressive cervical change
Ruptured membranes but no contractions yet. What is this condition called?
PPROM (Prelabour premature rupture of membranes)
What are some complications of PPROM?
- Preterm delivery (resulting in neonatal morbidity (e.g. low birth weight, resp hypoplasia, sepsis))
- Chorioamnionitis (inflam of foetal membranes due to bacterial infection) leading to sepsis in baby &/or mother
- Abruption
What does a negative fFN (foetal fibronectin) show?
Labour unlikely in the next 2 weeks
(If positive, likely in next 2 weeks–therefore steroids, tocolysis, analgesia & hospital observation may be indicated)
What is management for PPROM after speculum exam- cervic closed & negative fFN test (also got high vaginal swab for infection)?
Prophylactic Abx to reduce risk of chorioamnionitis & corticosteroids (IM dexamethasone or betamethasone)
Corticosteroids administered to induce foetal lung maturation-effect is maximal 24hrs after second dose
What are tocolytics used for?
To stop contractions to allow time for steroids to work before birth or allow transfer to an appropriate facility for birth