Overview

What is placental abruption?

Placental abruption, also known as abruptio placentae, occurs when the placenta detaches from the uterus before childbirth. The placenta is a temporary organ that links a developing fetus to the uterus while pregnant. It adheres to the wall of the uterus, typically at the top or side, and acts as a vital connection providing nutrients and oxygen to the fetus via the umbilical cord. The placenta is responsible for eliminating waste from the baby's blood.¹

During placental abruption, the placenta can separate fully or partially. This can potentially reduce the oxygen and nutrients the fetus receives. It is also able to result in significant bleeding in the parent giving birth.

Placental abruption typically happens in the later part of the third trimester, which starts at approximately 28 weeks gestation and continues until birth (around 40 weeks). However, it can happen at any point following 20 weeks.

There are two types of placental abruption

1. Partial placental abruption: occurs when the placenta doesn't completely detach from the uterine wall
2. Complete placental abruption: occurs when the placenta completely detaches from the uterine wall and causes vaginal bleeding. Typically, there is a greater amount of vaginal bleeding observed

Complete placental abruption is further classified into three subtypes:

Revealed placental abruption

After the placenta separates the blood flows downward between the membranes and uterine wall. Eventually, blood comes out of the cervical canal and becomes visible externally. This is the most common type.

Concealed placental abruption

Blood accumulates either behind the detached placenta or in the space between the membranes and the uterine lining. The presenting part prevents the collected blood from coming out from the cervix, which applies pressure to the bottom section. At times, the blood may percolate into the amniotic sac after rupturing the membranes. In any of these circumstances, blood is not visible outside. This type is rare.

Mixed placental abruption

In this type, some of the blood is collected inside and some is expelled from the cervix. Typically, one type is dominant over the other. This is quite common.

Risk factors

While the cause of abruption is often unknown, it has been associated with trauma or injury to the abdomen, swift depletion of amniotic fluid, and existing placental harm; but there are some risk factors associated with this, which are:²

1. Maternal age: placental abruption is more common in older mothers, with individuals over 40 being 2.3 times more likely to experience it compared to those under 35.

2. Racial background or cultural heritage: more serious cases of abruption occur more frequently in African-American and white individuals compared to Asian or Latin-American individuals, with rates of 1 in 200, 1 in 300, and 1 in 350, respectively.

3. History of genetics and family: severe cases of placental abruption are linked to a higher likelihood of abruption in sisters. Elevated homocysteine levels can result in thrombosis and spiral artery damage, which can cause placental abruption. Mutations in the methylenetetrahydrofolate reductase gene lead to hyperhomocysteinemia by disrupting the normal remethylation process. Folate and pyridoxine supplementation can decrease this.

4. Pregnancy-related high blood pressure conditions: women with gestational hypertension, pre-eclampsia, chronic hypertension, or chronic hypertension with superimposed pre-eclampsia have a doubled risk of placental abruption. 

5. Premature rupture of membranes: early breakage of the amniotic sac before the 37th week of pregnancy. The incidence of abruption can reach 5% after PROM.

6. Smoking: cigarettes double the risk of abruption.

7. Cocaine: the use of cocaine can lead to serious cases of abruption, which could lead to the birth of a stillborn baby.

8. Blood clotting disorder: anticoagulant lupus and conditions that increase the risk of blood clots. Mixed evidence exists regarding the relationship between lupus anticoagulants, thrombophilias, and placental abruption.

9. Uterine fibroids and torsion: the occurrence of placental abruption is more common in individuals with fibroids, especially when they are located at the placental implantation site and when the myoma volume is over 200 mL. Uterine torsion and intrauterine infection are also factors of placental abruption.

10. History: placental abruption that occurred earlier. Individuals who have experienced a severe placental abruption in the past are more likely to have another abruption in the future, with the risk increasing with each additional previous occurrence.

11. Multiparity/multigravida: there is inconsistent information about the higher risk for women with multiple children.

12. Poly or oligohydroaminos

Signs and symptoms

Placental abruption typically occurs during the later part of pregnancy. However, it is crucial to seek medical attention if you experience these symptoms during any stage of your pregnancy.³

1. Vaginal bleeding: the majority of individuals experiencing placental abruption will have bleeding from the vagina. While this is the prevailing indication of placental abruption, it may not be present in all cases. Therefore, it is crucial to seek assistance if you are experiencing any additional symptoms, regardless of whether you are not bleeding.

2. Abdominal pain: another prevalent sign of placental abruption is stomach pain or cramping. The degree of pain experienced with an abruption may differ. Some individuals experience a sensation of bruising in their abdomen, while others perceive the pain as extremely severe or excruciating.

3. Contractions: some individuals may begin experiencing contractions or feel their abdomen becoming firm or tight.

4. Lower back pain: some individuals experience pain in their lower back. This could occur in the presence of a hidden abruption. This is the location of blood flow behind the placenta, ensuring there is no vaginal bleeding.

5. Fetal distress, such as an irregular heart rhythm, can occur.

Placental abruption is classified into three grades.⁴

Grade 1. Some slight vaginal bleeding coupled with a few uterine contractions. However, there are no indicators of fetal distress or low blood pressure in the mother.

Grade 2. Some bleeding and moderate uterine contractions. The infant's heart rate could indicate signs of trouble.

Grade 3. Bleeding of moderate to severe intensity or concealed bleeding. In addition, continuous uterine contractions, abdominal discomfort, decreased blood pressure, and fetal demise.

Diagnosis

The signs and symptoms of placental abruption may resemble those of other pregnancy issues like placenta previa and pre-eclampsia. Data that could be utilised for the diagnosis of placental abruption comprises:⁵

1. History of medical conditions
2. Examining the physical state, which involves assessing the tenderness and tone of the uterus
3. Internal inspection of the vagina and cervix, utilising a speculum
4. Blood test
5. Ultrasound is used for evaluating the placenta
6. Monitoring the heartbeat of the fetus

At times, placental abruption may not be definitively diagnosed until delivery, when the placenta is discharged along with a blood clot that looks aged instead of new. The placenta is typically sent to a lab for additional diagnostic tests.

Treatment

It is important to closely monitor all suspected cases of placental abruption, no matter how severe, to ensure the health and safety of both the mother and child. Typically, this monitoring occurs in hospital and should involve routine monitoring of the vital signs of both the mother and baby. The treatment will vary based on how serious the condition is, but options may comprise:⁵

1. Less severe situations during the early stages of pregnancy - if the baby shows no signs of distress and if the vaginal bleeding ceases, you might be permitted to return home and take a break. Schedule appointments with your doctor for routine check-ups and if any changes occur in your condition.

2. In mild instances during the initial stages of pregnancy, you might have to remain in the hospital until it is safe for the doctor to induce labour. Medications may be suggested by the doctor to assist in the acceleration of the baby's lung development before delivery.

3. In pregnancies reaching 36 weeks or more, the doctor may advise delivery for mild to moderate cases. There is a chance for a natural delivery. Nonetheless, if the placenta detaches more from the uterine wall during childbirth, the physician may opt for an urgent cesarean section.

5. In severe instances, the safest option is to opt for immediate delivery. The mother may need care and support. Severe maternal haemorrhage can be managed with either a blood transfusion, emergency hysterectomy, or both.

Complications

• Disseminated intravascular coagulation (DIC)
• Hemorrhagic shock
• Maternal death
• Recurrence risk in future pregnancies
• Fetal anemia
• Fetal death⁶

Prevention

It is not possible to avoid placental abruption completely, but you can reduce some specific risk factors. For instance, avoid smoking or consuming illegal substances like cocaine. Collaborate with your healthcare provider to keep track of your high blood pressure.

It is important to always have your seatbelt on while in a car. If you have experienced abdominal trauma, such as from a car crash, fall, or other injury, it is important to seek immediate medical assistance.

If you've experienced a placental abruption and are thinking about trying to get pregnant again, consult with your healthcare provider before trying to see if there are steps you can take to lower the chances of another abruption.⁷

Summary

Placental abruption is a severe pregnancy complication in which the placenta separates from the uterus before delivery, possibly causing decreased oxygen and nutrients to reach the unborn child and substantial blood loss for the expectant mother. Various kinds of placental abruption exist, with known risk factors, signs and symptoms, diagnosis, treatment, and potential complications.

Seeking medical attention is essential if signs of placental abruption occur while pregnant. Different treatment options are available based on how serious the condition is and how far along the baby is in development. It is crucial to closely monitor and follow up on suspected cases of placental abruption to guarantee the well-being of both the mother and child.