Early Pregnancy Flashcards
What is placenta praevia?
Where the placenta is fully/partially attached to the lower uterine segment.
It is an important cause of antepartum haemorrhage (vaginal bleeding from 24 weeks gestation until delivery)
What are the 2 main types of placenta praevia?
Minor placenta praevia (placenta is low, but does no cover the interval cervical os)
Major placenta praevia (the placenta lies over the internal cervical os)
What is wrong with having a low-lying placenta?
It is more susceptible to haemorrhage possibly due to defective attachment to the uterine wall. Bleeding can be spontaneous, or provoked by mild trauma e.g. vaginal examination.
Also the placenta may be damaged by the presenting part of the foetus as it moves into the lower uterine segment in preparation for labour.
What are the risk factors for placenta praevia?
Previous C section (main risk factor)
High parity
Maternal age >40
Multiple pregnancy
Previous placenta praevia
History of uterine infection e.g endometritis
Curettage to the endometrium after miscarriage or termination
What are the clinical features of placenta praevia?
Painless vaginal bleeding (from spotting to massive haemorrhage (APH)) - but pain if the woman is in labour.
Examination may reveal risk factors e.g. c section scar, multiple pregnancy.
The uterus is usually non-tender on palpation.
What are the important questions to ask in antepartum haemorrhage?
How much bleeding and when did it start? Is it fresh red or old brown blood? Was the blood mixed with mucous? Could the waters have broken (membranes ruptured? Was it provoked (post-coital)? Is there any abdominal pain? Are the foetal movements normal? Are there any risk factors for abruption? E.g. smoking/drug-use/trauma - domestic violence
What should be looked for on general examination of a patient with antepartum haemorrhage?
Pallor, distress, cap refill, cold peripheries
Is abdo tender?
Does the uterus feel woody/these (may indicate placental abruption)
Are there palpable contractions?
Check the lie and presentation of the foetus (USS can help)
Check foetal well-being with CTG at 26 weeks or above
How is bleeding assessed in antepartum haemorrhage?
Externally e.g. looking at pads
Cusco speculum - avoid this until placenta praevia has been excluded
- look for blood, clots, cervical lesions, cervical dilation, any chance membranes have ruptured
Triple genital swabs to exclude infection if bleeding is minimal.
Digital vaginal examination (only when placenta praevia and ROM excluded) - can help to establish when their the cervix is beginning to dilate
Placenta praevia is an important cause of antepartum haemorrhage, but it is not the most common. What are the differentials for antepartum bleeding?
Placental abruption (part or all the placenta separates from the wall of the uterus prematurely)
Vasa praevia
Uterine rupture
Local genital causes (polyps, carcinoma, cervical ectropion)
Infections e.g. candida, bacterial vaginosis, chlamydia
What is vasa praevia?
Where foetal blood vessels run near the internal cervical os.
Characterised by vaginal bleeding, rupture of membranes and foetal compromise
The bleeding occurs following membrane rupture when there is rupture of the umbilical cord vessels, leading to loss of foetal blood and rapid deterioration in foetal condition
What is uterine rupture?
A full-thickness disruption of the uterine muscle and overlying serosa.
Usually occurs in labour with a history o previous c section/previous uterine surgery such as myomectomy
What are the investigations that are done for placenta praevia?
FBC (anaemia), clotting profile, Kleihauer test (if rhesus negative), G&S, cross-match
Exclude HELLP - (U&Es, LFTs)
Assess foetal wellbeing (CTG)
USS (definitive diagnosis) - distance between the lower edge of the placenta and internal os
What is the management for placenta praevia?
Resuscitation
Placenta praevia identified at a 20 week scan in an asymptomatic patient
- if minor - repeat scan in 36 weeks (placenta likely to move superiorly)
- if major - repeat at 32 weeks - plan for delivery should be made
C section safest mode at 38 weeks
Give anti-D within 72 hours of the onset of bleeding for Rh-ve woman
What is placental abruption?
A part or all of the placenta separates from the wall of the uterus prematurely.
An important cause of antepartum haemorrhage
Vaginal bleeding from week 24 of gestation until delivery
Describe the pathophysiology of placental abruption.
Thought to occur following a rupture of the maternal vessels within the basal layer of the endometrium.
Blood accumulates and splits the placental attachment from the basal layer.
The detached portion of the placenta is unable to function, leading to foetal compromise.
What are the 2 types of placental abruption?
Revealed (bleeding tracks down from the site of the placental separation and drains through the cervix)
Concealed (the bleeding remains within the uterus and typically forms a clot retroplacentally)
- the bleeding is not visible, but can be severe enough to cause systemic shock
What are the risk factors for placental abruption?
Previous placental abruption Pre-eclampsia/other hypertensive disorder Abnormal lie of the baby Polyhydraminos Abdominal trauma Smoking or drug use Bleeding in the first trimester, particularly if haematoma seen inside uterus on first trimester scan Underlying thrombophilia Multiple pregnancy
