Placental abruption and praevia Flashcards
What is placental abruption?
- Where 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 until delivery.
- Abruption is thought to occur following the rupture of maternal vessel within the basal layer of the endometrium.
- Blood accumulates and splits the placental attachment from the basal layer.
- Detached portion of placenta unable to function leading to rapid foetal compromise.
Two main types of placental abruption?
- Revealed abruption - bleeding tracks down from the site of placental separation and drains throughout the cervix - vaginal bleeding.
- Concealed abruption - bleeding remains within the uterus - typically forms a clot retroplacentally. The bleeding is not visible - but can be severe enough to cause systemic shock.
Risk factors for placental abruption:
1) Placental abruption in previous pregnancy
2) Pre-eclampsia or other hypertensive disorders
3) Abnormal lie of baby (transverse)
4) Polyhydramnios
5) Bleeding from first trimester (if haematoma seen on first trimester scan)
6) Underlying thrombophilia
7) Abdominal trauma
8) Multiple pregnancies
9) Smoking/drug use (cocaine)
Clinical features of placental abruption?
1) ANTEPARTUM HAEMORRHAGE
2) Painful vaginal bleeding (if revealed, not visible if concealed)
3) Pain between contractions in labour
4) Uterus on examination: woody/tense, and painful on palpation
Ddx of placental abruption?
1) Placenta praevia - fully or partially attached to the lower uterine segment
2) Marginal placental bleed - small, partial abruption large enough to cause revealed bleed, but not large enough to cause maternal/foetal compromise.
3) Vasa praevia - Fetal blood cells run near the internal cervial os - characterised by triad of vaginal bleeding, rupture of membranes and foetal compromise. (Bleeding occurs following membrane rupture when there is rupture of the umbilical cord vessels - leading to loss of foetal blood and rapid deterioration in feotal condition.
4) Uterine rupture - full-thickness disruption of the uterine muscle and overlying serosa. Occurs in labour with a history of previous caesarian section or previous uterine surgery such as myomectomy.
5) Local genital causes: polyps, carcinoma, cervical ectropion (common), or infections such as candida, bacterial vaginosis and chlamydia.
Investigations of placental abruption?
If major bleeding suspected, resuscitate and perform investigations simultaneously.
- Haemotology:
1) FBC - any maternal anaemia?
2) Clotting profile
3) Kleinbauer test - determine if mother is rhesus negative in order to determine the amount of foeto-maternal haemorrhage and thus the dose of Anti-D required.
4) Group and save - if blood group unknown
5) Cross-match - if transfusion may be required - Biochemistry: TO exclude hypertensive disorders including pre-eclampsia and HELLP syndrome (any other organ dysfunction):
1) U&Es
2) Liver function tests - CTG to assess foetal well-being - in women above 26 weeks gestation.
- Imaging: An ultrasound scan performed when patient I stable - in placental abruption a retroplacental haematoma might be seen (poor negative predictive value should not be used to exclude._
Management of placental abruption?
- If antepartum haemorrhage significant - ABCDE approach - do not delay maternal resuscitation in order to determine foetal viability.
1) Emergency delivery - indicated in the presence of maternal/foetal compromise - usually by caesarian section unless spontaneous deliver is imminent or operative vaginal birth is achievable (even if in-utero foetal death diagnosed, C-section indicated if maternal compromise).
2) Induction of labour - haemorrhage at term without maternal or foetal compromise, induction of labour recommended to prevent further bleeding.
3) Conservative management - some partial or marginal abruptions not associated with maternal/foetal compromise.
ALL CASES GIVE ANTI-D within 72 HOURS, IF WOMAN IS RHESUS D NEGATIVE.
What is placenta praevia?
- Where placenta is fully or partially attached to the lower uterine segment - important cause of antepartum haemorrhage (vaginal bleeding from 24wk until delivery).
Two types - minor and major. - Minor placenta praevia - low placenta but does not cover internal cervical os.
- Major placenta praevia - placenta lies over internal cervical os.
Low lying placenta is more susceptible to haemorrhage possible due to defective attachment to uterine wall - can be spontaneous or provoked by mild trauma (examination). Placenta may be damaged as presenting part of the foetus moves into lower uterine segment in preparation for birth.
Risk factors of placenta praevia?
1) PREVIOUS CAESARIAN SECTION
2) High parity
3) Maternal age >40
4) Multiple pregnancy
5) Previous uterine infections (endometritis)
6) Curettage to endometrium for miscarriage or termination
Clinical features of placenta praevia?
1) ANTEPARTUM HAEMORRHAGE
2) Classic PAINLESS VAGINAL BLEEDING - vary from spotting to massive haemorrhage, can be pain during labour.
3) Uterus not tender palpation
4) O/E - previous c-section scar? Multiple pregnancy?
Ddx of placenta praevia?
1) Placental abruption
2) Vasa praevia - fetal blood vessels run near internal cervical os characterised by a triad of vaginal bleeding, rupture of membranes and foetal compromise (membrane rupture due to rupture of umbelical cord vessels - loss of foetal blood and rapid deterioration in fetal condition.
3) Uterine rupture - full thickness disruption of the uterine muscle and overlying serosa.
4) Local genital causes - polyps, carcinoma, ectropion, infections - candida, vaginosis, chlamydia.
Investigations of placenta praevia?
- Haematology:
1) FBC
2) Clotting factors
3) Kleihauer test ( if rhesus negative to determine dose of anti-D dependant on vol of feto-maternal haemorrhage)
4) Group and save
5) Cross-match - Biochemistry: to exclude pre-eclampsia or HELLP or other organ dysfunction.
1) U+E
2) LFT’s - CTG to assess foetal wellbeing if over 26 weeks gestation
- Imaging - definitive diagnosis of placenta praevia is via ultrasound - short distance between lower edge of placenta and internal os.
Management of placenta praevia?
- Any presenting with significant antepartum haemorrhage - ABCDE and do not delay resuscitation to determine fetal viability.
- (may be identified in 20 week ultrasound scan)
Placenta praevia minor - repeat scan at 36 weeks recommended as placenta likely to have moved superiorly.
Placenta praevia major - repeat scan at 32 weeks and a plan for delivery.
In cases of confirmed placenta praevia - C-Section is the safest mode of delivery, placenta praevia major usually warrants an elective C-section at 38 weeks.
IN ALL CASES OF ANTEPARTUM HAEMORRHAGE GIVE ANTI-D WITHIN 72 HOURS IF MOTHER IS RHESUS NEGATIVE.
