A 34-year-old woman, 33 weeks pregnant presents to her GP with a headache she has had for two days and increasing facial and lower limb oedema. She is previously fit and well and in her first pregnancy. Blood pressure is found to be 139/90 mmHg (booking blood pressure was 110/66). Urine dipstick shows no proteinuria. The GP advises paracetamol, to keep her legs elevated and to return the next day for a further blood pressure check.
The next day her blood pressure is 154/94 and she is now complaining of mild abdominal pain as well as headache. Palpation revealed some abdominal tenderness. On direct questioning she admits to a small amount of vaginal bleeding – ‘like the first day of a period’. The GP arranged immediate admission to the maternal assessment unit where she is given analgesia and foetal monitoring is started. The baseline heart rate appeared to be low with a few decelerations, so she was transferred immediately to the labour ward where monitoring was continued. She then had a further moderate vaginal bleed.
Monitoring was difficult because the maternal pulse of 120 bpm was confused with the foetal heart rate, so a portable ultrasound was used to determine foetal heart rate. On portable ultrasound the placenta appeared to be large and grossly abnormal, and the foetal heart rate was seen to be approximately 60 bpm. The decision was made for urgent caesarean section. At caesarean section there was approximately 300mls of blood clots behind the placenta. The baby was born in poor condition but recovered after a few inflation breaths. The diagnosis of placental abruption was made.
Incidence
Placental abruption is the separation of the placenta from its attachment to the uterine wall before the baby is delivered. It is usually reserved for pregnancies over 20 week’s gestation. Abruption is a significant cause of maternal and perinatal morbidity and perinatal mortality, and complicates 0.4-1% of pregnancies. The perinatal death rate is approximately 12%.1 The majority of perinatal deaths (up to 77%) occur in utero – deaths in the postnatal period are primarily related to preterm delivery.2
Risk factors
These include:3,4
– Cigarette smoking
– Grand multiparity
– Alcohol and cocaine use
– Advanced maternal age
– Diabetes
– Uterine fibroids
– High blood pressure
– Thrombophilias
– Premature rupture of membranes
– Infection
– Pre-eclampsia
– Foetal growth restriction
– Low BMI
– Non-vertex presentation
– Increased uterine distension (multiple pregnancies, polyhydramnios)
– Previous history – after one episode of placental abruption there is at least a 10% chance that the condition will recur and a 9-25% of women with two previous pregnancies complicated by abruption
– Pregnancy following assisted reproductive techniques
– First trimester bleeding increases the risk of abruption later in the pregnancy.
Direct causes are rare but include direct injury to the abdomen, which may be associated with domestic violence and sudden loss of uterine volume (with rapid loss of amniotic fluid or after delivery of the first twin).
Symptoms and signs
– Vaginal bleeding (70–80%), however the bleeding can be concealed, revealed or mixed.
– Abdominal pain (50%) – commonly constant in contrast to uterine contractions.
– Uterine tenderness (70%) – the uterus may feel woody hard.
– Uterine contractions (35%) – abruptions can occur in labour or stimulate labour to begin.
– Reduced foetal movements.
– Foetal distress or intrauterine death.
– Evidence of hypovolemic shock.
– Evidence of disseminated intravascular coagulopathy – non-clotting vaginal bleeding, bleeding from drip sites and skin bruising.
– Retroplacental clots can be seen on ultrasound in 2-25% of cases. Foetal cardiac monitoring.
Differential diagnosis
– Pre-term labour.
– Vasa previa – bleeding from a vessel crossing the fetal membranes.
– Vaginal trauma.
– Malignancy (rare).
– Vaginitis.
– Placenta praevia – this is why digital vaginal examination should not be done until the placental location is known.
Management
Acute abruption can be life threatening for the mother and foetus, so pregnant women with signs and symptoms of abruption should be referred immediately for evaluation.
Management of these pregnancies is determined on a case-by-case basis, and will depend upon the severity of the abruption, the gestational age, and maternal and foetal status. Any patient who presents with even slight bleeding from placental separation is at risk of developing sudden severe abruption, and all of these patients should be monitored and undergo continuous foetal heart rate assessment.
Immediate delivery of the foetus may be indicated if it is mature, or if the foetus or mother is in distress.
Blood volume replacement to maintain blood pressure and blood plasma replacement to maintain fibrinogen levels may be needed. Vaginal birth is usually preferred over caesarean section unless there is foetal distress. Caesarean section is contraindicated in cases of disseminated intravascular coagulation.
If the baby is very premature and there is only a small placental separation, the mother may be kept in hospital for close observation. She may be released after several days if the condition does not get worse and any bleeding stops.
Prevention
Although the risk of placental abruption cannot be eliminated, it can be reduced – avoiding smoking, alcohol, cocaine and reducing physical trauma, particularly domestic violence. Recognising these risk factors and ensuring appropriate follow up of those with risk factors in secondary care.
A systematic review of folic acid supplements in pregnancy found no conclusive evidence of benefit in women who took folic acid supplements. In contrast, an observational study conducted investigating vitamin supplementation and risk of placental abruption found that women who use folic acid and multivitamins during pregnancy are significantly less likely than non-users to develop placental abruption.5 There is no good data to support a role for antithrombotic therapy in the prevention of abruption in women with thrombophilia.
Professor Sian Jones is a consultant obstetrician and gynaecologist and honorary professor at Bradford Teaching Hospitals NHS Foundation Trust and the University of Bradford
Dr Suhair Ibrahim is an ST3 in obstetrics and gynaecology at Bradford Teaching Hospitals NHS Foundation Trust.
References
1 Ananth CV, Wilcox AJ. Placental abruption and perinatal mortality in the United States. American Journal of Epidemiology, 2001; 153 (4): 332-337
2 Tikkanen M, Luukkaala T, Gissler M et al. Decreasing perinatal mortality in placental abruption. Acta Obstetricia et Gynecologica Scandinavica, 2013; 92 (3): 298-305
3 Tikkanen M. Placental abruption: epidemiology, risk factors and consequences. Acta Obstetricia et Gynecologica Scandinavica, 2011; 90 (2): 140-149
4 Pariente G, Wiznitzer A, Sergienko R et al. Placental abruption: critical analysis of risk factors and perinatal outcomes. Journal Maternal-Fetal and Neonatal Medicine, 2011; 24 (5): 698-702
5 Nilsen RM, Vollset SE, Rasmussen SA et al. Folic acid and multivitamin supplement use and risk of placental abruption: a population-based registry study. American Journal of Epidemiology, 2008; 167: 867–874
Further reading
Francois KE, Foley MR. Antepartum and postpartum hemorrhage. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics – Normal and Problem Pregnancies. 6th ed. Philadelphia, PA: Elsevier Saunders; 2007: chap 19.
Houry DE, Salhi BA. Acute complications of pregnancy. In: Marx J, Hockberger RS, Walls RM, et al, eds. Rosenae’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Elsevier Mosby; 2009:chap 176.
Cunningham FG, Leveno KL, Bloom SL et al. Obstetrical hemorrhage. In: Cunningham FG, Leveno KL, Bloom SL, et al., eds. Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010: chap 35.
