Sickle Cell Anemia in Pregnancy: An Overview

Introduction

Sickle cell disease (SCD) is when the body's red blood cells (RBC) are changed to a sickle shape. RBCs supply oxygen to the entire body. In healthy people, red blood cells are round and flexible. They circulate easily in the blood. People with sickle cell disease have stiff red blood cells that can block blood flow. This can cause pain, infection, and sometimes organ damage and stroke. SCD can lead to anemia. Anemia occurs due to a deficiency of adequate healthy RBCs that carry oxygen to the rest of the body.

What Causes SCD?

SCD is inherited. This means it is passed from parent to child through genes that are part of the cells in the body that store instructions for how the body grows and functions. Genes come in pairs - one gene from each pair from each parent, and sometimes, the instructions in genes change, which is called genetic change or mutation. Parents can pass on genetic changes to their children that can prevent a gene from working properly. Sometimes, this can cause birth defects or other health problems. A birth defect is a health problem that appears in a child at birth.

The genetic change for sickle cell disease is inherited from both parents to get SCD. Genetic change from one parent leads to sickle cell trait. This means the person may be susceptible to acquiring SCD due to the genetic change, but they do not suffer from the illness. When this happens, the person is called a carrier. Carriers have the genetic change but do not get the disease. Sickle cell trait does not transform into SCD. It is rare for people with sickle cell trait to have signs of sickle cell disease, but this is unusual.

Can SCD or Sickle Cell Trait Be Passed Down From Parent to Child?

SCD, or sickle cell trait, is indefinitely passed down from parents to children. But it depends on both the parents. If both have SCD, the baby will also have it.

If both have sickle cell trait, then the chances are as follows:

• There is a 75 percent chance that the fetus will not suffer from sickle cell disease.

• There is a 50 percent chance that the fetus will have sickle cell disease.

• There is a 25 percent chance that the fetus will have sickle cell disease.

• There is a 25 percent chance that the fetus will not have SCD or sickle cell trait.

How to Diagnose SCD or Sickle Cell Trait?

There are two varieties of tests that can tell whether a person has sickle cell disease or not. Both are safe to use during pregnancy.

• Blood Tests: A method called high-performance liquid chromatography (HPLC) is used to check for sickle cell trait or sickle cell disease, which recognizes the type of hemoglobin present.

• Swab Test: In this test, the doctor will rub a cotton ball on the inside of the cheek on both sides to collect samples of cheek cells that contain DNA (deoxyribonucleic acid).

A person may consider undergoing tests if: SCD, or sickle cell trait, runs in one of the families. To help find out, take a look at the family's medical history.

In the United States, SCD is the most common in black or Hispanic groups.

Is It Possible to Diagnose Sickle Cell Trait or Disease During Pregnancy?

Sickle Cell Trait or disease can be easily diagnosed. If one of the parents has SCD or sickle cell trait, prenatal testing can be performed to determine if the baby has SCD or sickle cell trait.

Take one of the following tests:

• Chorionic villus sampling (also called CVS). This test examines placental tissue for birth defects and genetic conditions. CVS can be done from 10 to 13 weeks of pregnancy.

• Amniocentesis (also called amnio). This test checks the amniotic fluid in the amniotic sac surrounding the baby to detect birth defects and genetic conditions.

What Problems Can Sickle Cell Disease Cause During Pregnancy?

Complications include pain, infection, and vision problems. During pregnancy, sickle cell disease may become more severe. Pain often occurs in organs and joints. They can last from a few hours to a few days, but some last for weeks.

During pregnancy, sickle cell disease may increase the risk of:

• Miscarriage.

• Premature birth is when birth occurs too early, before the 37th week of pregnancy.

• Low birth weight.

What Is the Management of Side Effects of SCD During Pregnancy?

Six key adverse events require effective planning and management to provide better outcomes for mothers and newborns, as described below:

• Pain – Pregnant women experiencing an embolic attack should be admitted to the hospital and given adequate bed rest and fluid intake. To relieve pain, Paracetamol may be prescribed. If the pain does not improve, narcotic pain relievers can be used.

• Acute Chest Syndrome (ACS) – Pregnant women with sickle cell disease who complain of severe cough and chest pain should be evaluated for ACS. Pulmonary infiltration on chest X-ray and blood and sputum cultures are performed to check for infectious complications. Treatment includes appropriate antibiotics, oxygen, rehydration, pain medication, and blood transfusion if necessary.

• Pulmonary Embolism – Women presenting with chest pain and respiratory distress with a normal chest X-ray should be suspected of having a pulmonary embolism (blood clot blocking the blood supply to lung arteries). Treatment with LMWH (Low molecular weight Heparin) should be initiated pending confirmation of the diagnosis.

• Stroke – Ischemic and hemorrhagic stroke (occurs when blood from an artery suddenly begins bleeding into the brain) should be suspected in any woman with acute neurological deterioration. The treatment of choice is an emergency exchange transfusion.

• Hematological Complications – Anemia is the most common complication of pregnancy. It is caused due to blood loss, bone marrow suppression due to parvovirus infection, and nutritional deficiencies. Prophylactic red blood cell transfusions are performed in some cases because the risk of complications such as stroke or ACS is believed to be reduced. HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome may develop in up to 10 percent of women with preeclampsia (hypertension during pregnancy). It can be managed conservatively or by emergency delivery, depending on gestational age.

• Infection – The main sites of infection are the urinary tract and respiratory system. Less common are postpartum endometritis (inflammation of endometrium), hepatitis, transient bacteremia, osteomyelitis (bone marrow disorder), and HIV. During infection, fever and acidosis lead to increased and worsening sickle anemia. Appropriate antibiotics should be started as soon as possible to avoid further complications. Such attacks may mimic sickle cell disease and hepatitis. Liver function tests and ultrasound evaluation will help make the diagnosis. Antibiotics and symptom management, followed by selective cholecystectomy (removal of the gallbladder), are recommended in the postpartum period.

How Is Sickle Cell Disease Treated During Pregnancy?

1. Fresh blood transfusions are advised during the pregnancy or gestation period.

2. Since women with sickle cell disease are at high risk of developing complications, the use of low-dose Aspirin 75 mg once daily starting at 12 weeks of pregnancy in an attempt to lower the chance of pre-eclampsia (a serious pregnancy complication that is characterized by high blood pressure) will be suggested.

3. Women with SCD should be advised to receive preventive low-molecular-weight heparin throughout prenatal hospitalizations.

4. Though Hydroxyurea is the recommended medication for sickle cell disease, unfortunately, it is contraindicated in pregnancy.

Conclusion

The literature on perinatal outcomes of sickle cell disease is limited, and the potential impact of further improvements in modern obstetric care and sickle cell disease treatment is significant; there is a necessity for additional research on pregnancy-related complications and outcomes for women with sickle cell disease. Effective pregnancy management and complications in women with sickle cell disease are required to ensure good outcomes for mothers and newborns.