Successful outcome in a compound heterozygote haemoglobin E/beta-thalassaemia in pregnancy

Abstract

Haemoglobin E (HbE) affects at least 1 million people around the world. The carrier frequency of HbE/beta-thalassaemia (HbE/β-thalassaemia) is highest in Southeast Asia. In India, the highest frequency is observed in the northeast region. Distinguishing between homozygous HbE disease and HbE/β-thalassaemia is a challenge to the haematopathologist as well as to the treating obstetrician because both are clinically and haematologically similar, posing a difficulty in managing anaemia and assessing the fetal risk for the same disease. This article reports a case of compound heterozygote HbE/β-thalassaemia in pregnancy and its successful outcome.

Background

Thalassaemia is a single-gene disorder characterised by defective globin chain synthesis because of varied genetic mutations. It is an autosomal recessive disorder, where the defect may lie in either of the two globin chains namely alpha and beta. Haemoglobin E (HbE) (α2β226glu-lys) is the most common Hb variant in Southeast Asia and the second most prevalent globally. There is a substitution of glutamate to lysine in codon #26 of the beta (β)-globin gene, resulting in structurally abnormal Hb and behaving like a mild form of β-thalassaemia. However, HbE/β-thalassaemia when coexisting may lead to severe anaemia and is responsible for approximately one-half of all severe β-thalassaemia cases worldwide.¹

In India, HbE was mostly confined to the north-eastern states; however, the migration of people from these endemic areas has led to increased prevalence in other parts of the country. Identification of this Hb variant is important because women with compound heterozygous HbE/β-thalassaemia may present clinically as thalassaemia major and if not treated can have serious complications.² We present a case of a third gravida woman in her 20s, who was found to have compound heterozygous HbE/β-thalassaemia and discuss the management protocol of coexisting HbE and β-thalassaemia during pregnancy.

Case presentation

A third gravida woman in her 20s with previous two caesarean sections having one live issue and one stillborn presented to us at 16 weeks’ gestation with dyspnoea and undue fatigue. A detailed history revealed that in her first pregnancy, she had three units of packed red blood cells (PRBCs) transfusion in the antenatal period at a peripheral health centre without appropriate evaluation. Her blood group was found to be Rhesus (Rh) negative, but her partner’s blood group was not done. She underwent a caesarean section for obstructed labour and the baby was stillborn. No gross abnormalities were present in the baby externally. Autopsy was likely not offered. The patient had a prolonged stay in the hospital due to wound dehiscence and required three units of PRBCs transfusion during the postnatal period. She also received anti-D 300 µg intramuscularly postnatally.

In her second pregnancy, she received more than six units of PRBCs transfusion and had a preterm caesarean section (cause unknown). The baby’s blood group was A positive and the direct Coombs test was positive. The anti-D injection was not received in this pregnancy antenatally. The baby received phototherapy and exchange transfusion and is alive and healthy.

In the current pregnancy, a thorough clinical examination revealed severe pallor and icterus along with tachycardia and normal blood pressure. On her abdominal examination, her uterus corresponded to the period of gestation and she had mild splenomegaly but no hepatomegaly.

Investigations

Relevant investigations were done which revealed Hb of 5.9 g/dL and ferritin level of 933 mg/dL. Further evaluation for typing of anaemia was done and she was found to have HbE/β-thalassaemia on high-performance liquid chromatography (HPLC) (figure 1). The HBB gene sequencing revealed heterozygous IVS 1–5 (C>G) mutation for β-thalassaemia and heterozygous mutation for HbE, making it compound heterozygous. Kidney and liver function tests were in the normal range. The HPLC of her partner was found to be normal. The cardiac MRI and liver MRI were normal (table 1); therefore, no chelation was given. She was also Rh alloimmunised with the anti-D antibody titre of 1:512. However, no signs of fetal anaemia were seen on ultrasonography, and middle cerebral artery peak systolic velocity (MCA-PSV) was <1 multiples of median. She was then followed regularly with MCA-PSV, which remained within normal limits.

Figure 1.

High-performance liquid chromatography of the patient (showing HbF 17.9% and HbA2 72.8% suspicious of harbouring a HbE/Beta thalassemia mutation which was confirmed by capillary electrophoresis)

Table 1.

Investigations of the case along with normal reference values in pregnancy

Parameters	Patient’s values	Reference values in pregnancy (3rd trimester)
Haemoglobin (g/dL) (1st trimester/post partum)	5.9/8.3	11.6–13.9 g/dL (1st trimester); 9.5–15 g/dL (3rd trimester)13
Leucocytes (×103/mm3)	13.49	5.9–16.9
Platelets (×109/L)	249	146-429
MCV (fL)/MCH (pg/cell)/MCHC (g/dL)	61/14.8/24.1	81–99/29–32/34±2
Blood group	A negative (woman), O positive (husband)
Serum ferritin ng/mL (1st trimester/post partum)	808/1560	6–130 (1st trimester); 10–150 (post partum)
Serum iron (µg/dL)	203	30–193
Serum total iron-binding capacity (µg/dL)	237	359–609
HPLC	HbA: 60.7, HbA2: 25, HbF: 12.7 (double heterozygous HbE and beta-thalassaemia trait	HbA2<3.5%, HbF <2%
MRI (liver)	Diffuse T2 hypointensity, involving liver parenchyma. Pancreas and spleen show normal intensity. T2* mean=6.8±1.2 ms Custom mean LIC: 3.9–94.5 mg/g	Liver iron <7 mg/g dry weight of liver
Cardiac MRI	T2* mean=54.6±4.0 ms	T2* >20 ms is normal (cardiac T2* <10 ms increases risk of cardiac failure)
2D-ECHO	Normal (left ventricular ejection fraction >60%)
Bilirubin (total) (mg/dL)	2.3	0.1–1.1
Aspartate aminotransferase (U/L)	20.5	4–32
Alanine aminotransferase (U/L)	9.5	2–25
Serum alkaline phosphatase (U/L)	55	38–229
Prothrombin time (s)/INR	12.3/1.02	9.6–12.9/0.80–0.94
Serum lactate dehydrogenase (IU/L)	270	105–333
Oral glucose tolerance test (mg/dL)	84/103/79	92/180/153
Serum urea (mg/dL)	21	1.6–4.4 mmol/L
Serum creatinine (mg/dL)	0.37	0.4–0.9
Total proteins/albumin/globulin	6.33/3.84/2.49
Fetal Doppler (30 weeks) MCA-PSV	45.2 cm/s, 1.007 MoM

Hb, haemoglobin; HPLC, high-performance liquid chromatography; INR, international normalised ratio; LIC, liver iron concentration; MCA, middle cerebral artery; MCH, mean corpuscular haemoglobin; MCHC, mean corpuscular haemoglobin concentration; MCV, mean corpuscular volume; MoM, multiples of median; PSV, peak systolic velocity.

Differential diagnosis

The differential diagnoses in our case were nutritional anaemia like iron deficiency anaemia, haemoglobinopathies and anaemia of chronic disease. We included nutritional deficiencies as first differential because of India being a developing country and major part of our general population falls in the lower or middle-lower class which has a restricted accessibility to proper food and sanitation supplies along with medicines and supplements needed during pregnancy. Difficult terrain in certain regions, lack of proper transport facilities and lack of awareness often create a hurdle in reaching to primary or secondary healthcare facilities for many pregnant patients. All these factors contribute to increasing nutritional deficiencies in the pregnant women. Thalassaemia is relatively common in our country and often first recognised during pregnancy when low or suboptimal Hb levels are recorded, and further evaluations are done to find out the exact cause.

Treatment

For the correction of anaemia, two units of PRBCs were transfused. At around 26 weeks, her Hb dropped to 6.2 g/dL and she was transfused again with two units of PRBCs.

Outcome and follow-up

After 27 weeks, she was lost to follow-up and presented in the emergency department in labour at 36 weeks. On examination, she had severe pallor with icterus. Abdominal examination revealed massive splenomegaly reaching up to the umbilicus. The liver was palpable at 3 cm below the costal margins at the mid-clavicular line. Uterine size corresponded to 32 weeks with a singleton fetus in breech presentation. Her Hb was now 6.9 g/dL and serum bilirubin was 2.3 g/dL.

The patient had an emergency caesarean section, and a baby boy of 2228 g was delivered with a blood group A positive and the direct Coombs test also came positive. The baby developed hyperbilirubinaemia and was started on phototherapy. Post-delivery, the patient’s Hb was 8.3 g/dL but this time serum ferritin was 1560 mg/dL. Because of her high serum ferritin levels and history of multiple transfusions, chelation therapy was started in the form of deferoxamine 360 mg once a day after consultation with the haematologist; and the woman was discharged with proper counselling and follow-up advice. Splenectomy was withheld at that moment as she was asymptomatic and was advised to be in constant follow-up. At her follow-up visit at 6 weeks, the patient was fine but again anaemic with serum ferritin 1828 ng/mL. A repeat cardiac MRI was not performed as the first one was done in the second trimester itself and the cost affordability was an issue for the patient. Therefore, serum ferritin values were used as a guide for chelation therapy. Chelation therapy was reinitiated as the patient had stopped that on her own. She was also given injection-depot medroxy progesterone acetate for contraception. All the necessary details were explained with the repeat and regular dosing at a 3-month interval to maintain the contraceptive efficiency. The patient is under follow-up and is symptomatically better.

Discussion

HbE gene is the mutant form of the β-globin gene. β-E chain is insufficiently produced because of a novel cryptic messenger RNA splice site, leading to thalassaemic indices.^3–6 Since its discovery in 1954, there are uncertainties about many aspects of its pathophysiology. HbE disorders may be found in heterozygous (AE), homozygous (EE) and compound heterozygous states. Both heterozygotes and homozygotes are asymptomatic, or minimally anaemic with microcytic and hypochromic RBCs. However, when the β-E allele interacts with a β-thalassaemia mutation in the compound heterozygous state, a variable, and often severe, anaemia may be seen with Hb levels ranging from 3 to 11 g/dL.^3–7

The majority of these patients have delayed puberty, and they suffer from subfertility and infertility likely due to endocrinal dysfunction. Moreover, when pregnant, these patients are at an increased risk of abortions, preterm delivery and intrauterine growth restriction due to hypersplenic crisis. There is also an increased risk of venous thromboembolism. To the best of our knowledge, there is a paucity of reported cases with successful pregnancy outcomes from India. Merchant et al described the successful outcome of a patient with HbE/β-thalassaemia with a twin pregnancy who had previously undergone uterine artery embolisation for intractable haemorrhage due to incomplete abortion in a previous pregnancy. This was possible due to appropriate blood management and chelation therapy.⁸

In our case, the patient received multiple blood transfusions in both her pregnancies without being evaluated for haemoglobinopathies; and despite the availability of anti-D prophylaxis, this woman became alloimmunised. This reflects the suboptimal care being provided at peripheral centres.

The keystones of treatment in β-thalassaemia are blood transfusion and iron chelation therapy. Multiple transfusions cause iron overload resulting in hepatic, cardiac and endocrine dysfunction.⁹ In the current era, early diagnosis, improved transfusion techniques and effective chelation protocols have improved the quality of life and survival of individuals with thalassaemia. The mortality from cardiac iron overload has significantly declined with the use of MRI methods for monitoring cardiac (cardiac T2*) and hepatic iron overload (liver T2*) and FerriScan for liver iron assessment.¹⁰ It is believed that the MRI techniques that identify and quantify iron in tissues can assess the amount of hepatic and cardiac iron. If cardiac iron overload is detected, patients at risk of heart failure can be determined timely before they develop symptoms. Cardiac T2* MRI has recently allowed for more accurate measurement of iron overload in the heart, allowing a better guide for managing iron chelation therapy with single or multiple chelators. T2* ≤25 ms usually prompts intensifying the iron chelation therapy (increasing doses or introducing combination therapy) and thus reduces the mortality due to cardiac failure.¹¹

In the index case, the woman remained asymptomatic during the non-pregnant state and had never received chelation therapy. She had a history of multiple blood transfusions only during the pregnancies. Although she had massive splenomegaly, her cardiac MRI and FerriScan were normal. It has been reported in the literature that transfusions are needed in most cases during pregnancy, even in those who have been non-transfusion dependent in the pre-pregnant state as seen in our case.¹² However, sometimes, splenectomy needs to be carried out after pregnancy for better haematology outcomes. Had her haemoglobinopathy been diagnosed earlier, it could have prevented the stillbirth and morbidity in the patient. However, other causes of stillbirths should also be evaluated.

Another important aspect in such cases is testing of the patient’s partner for evaluation for haemoglobinopathy and mutational analysis. This will aid in counselling of the couple about risk of recurrence and need for prenatal testing. In our case, the woman’s partner had a normal HPLC and so the fetus, at the most, would be a carrier of the haemoglobinopathy.

Our patient had a negative blood group, and the partner was Rh positive. The anti-D injection which was missed antenatally during her second pregnancy and the multiple transfusions most probably led to the raised Rh antibody titre. The fetus did not develop anaemia in utero which was surprising as the Rh antibody titres were high and might have required intrauterine transfusion.

After managing this case, we can say that the pre-conceptional and antenatal period provides the treating physician an opportunity to screen such cases which otherwise would have remained undiagnosed or misdiagnosed as iron deficiency anaemia and would have received iron preparations leading to iron overload as our case received during her first pregnancy. Moreover, each stillbirth or neonatal death should have a thorough evaluation with detailed history and external and internal examination to reach a final diagnosis to prevent any such incidents in the next pregnancy. It would not be much to say that thalassaemia screening should be included as a mandatory test either pre-conceptionally or in the first trimester. Testing of the patient’s partner in such cases becomes equally important to know about the chances of the fetus being affected.

For Rh-negative pregnancy management, the anti-D injection should be given antenatally and postnatally after checking the indirect Coombs test. This decreases the chances of alloimmunisation to less than 0.2%. In case there is a history of any bleeding or haemorrhage during pregnancy, an anti-D injection should be administered. This could prevent alloimmunisation and hence the development of fetal hydrops and death in a lot of cases.

If the patient has already been alloimmunised, then the antibody titres play a major role to know the critical titre, and further regular monitoring with MCA-PSV is needed if the critical titre value is exceeded.

In-depth knowledge along with the facility to perform investigations is required to manage such cases and this is a drawback in low-resource settings where required investigations are not available and may lead to mismanagement.

Patient’s perspective.

I never knew the reason for receiving so many blood transfusions. No one did any tests to find out the exact cause of anaemia until I visited this hospital. I had two previous deliveries but did not receive anti-D antenatally in the second pregnancy despite my negative blood group. Now I know what my condition is and that it requires multiple doctors working together. I am also aware that follow up is required for me to maintain a healthy life. In addition, I can guide pregnant mothers of my locality to visit this hospital to get a better management in their pregnancy.

Learning points.

• Early recognition of these disorders is pertinent to prevent affected children from being placed on life-long transfusion therapy.

• Regular follow-up is essential to determine the steady-state haemoglobin level and to prevent an overload state and thus provide a healthy and disease-free life.

• Pre-conceptional counselling, optimal drug therapy in conjunction with a haematologist, invasive fetal testing, and regular follow-up are warranted and should be the approach for a healthy mother and healthy baby.

Ethics statements

Patient consent for publication

Obtained.