Anaemia In Pregnancy

Clinical anaemia in pregnancy is often asymptomatic and is mostly detected by blood tests done routinely at prenatal visits. Anaemia is very common in pregnant women. Those women who do not see a health care provider early in their pregnancy, or do not have any prenatal care at all, often have their anaemia detected very late in their pregnancy when it can be difficult to correct and is often associated with complications.

What is anaemia?
Anaemia is a condition of too few red blood cells, or a lowered ability of the red blood cells to carry oxygen or iron. Tissue enzymes dependent on iron can affect cell function in nerves and muscles. The fetus is dependent on the mother’s blood and anaemia can cause poor fetal growth, preterm birth and low birth weight.

Anaemia and pregnancy
Anaemia in pregnancy is very common and is present in almost 80% of pregnant women.
Normally during pregnancy, erythroid hyperplasia of the marrow occurs and red blood cell mass increases. The haematocrit value (the percentage of red blood cells relative to plasma volume) in non-pregnant women ranges from 38 to 45%. However, in pregnant women, because of hemodilution, normal values can be much lower: e.g. 34% in single and 30% in twin or multiple pregnancy even with normal stores of iron, folic acid and vitamin B12. This lower range simply reflects “the physiologic hemodilution of pregnancy” and does not indicate a decrease in oxygen carrying capacity or true anaemia. Iron deficiency is responsible for 95% of anaemia of pregnancy.
During pregnancy anaemia is defined as Haemoglobin (Hb) less than 10.0 g/dl (Hct less than 30%). If Haemoglobin (Hb) is < 11.5 g/dL at the onset of pregnancy, women may be treated prophylactically because subsequent hemodilution usually reduces Hb to < 10 g/dL. Despite hemodilution, O2-carrying capacity remains normal throughout pregnancy. Hct normally increases immediately after birth. Haemoglobin carries oxygen to body tissues via the red blood cells.

What are the main causes of anaemia in pregnancy?
The three main causes of anaemia in pregnancy in Anguilla are:
• Lack of production of red blood cells, mostly because of low concentrations of iron and other blood synthesising precursors, for example folate.
• Haemolysis of circulating blood cells
• A chronic repeated blood loss
Iron deficiency anaemia
Iron deficiency in pregnancy is usually due to a diet deficiency of iron. In rare cases iron absorption in the intestine is faulty. During pregnancy the utilisation of the body’s iron is increased. The total intake in pregnancy should be 700-1400 mg to allow for the increase in maternal haemoglobin concentration, fetal iron requirements and uterine growth. The daily requirement of iron for the pregnant woman should be 6mg a day.
Ensuring that the woman has a diet containing iron best prevents iron deficiency anaemia in pregnancy. Preferably this will entail eating foods with a higher iron content, including meat, egg yolks, beans, peas, dark green vegetables such as spinach, and dried fruits such as raisins and prunes. In Anguilla some pregnant women are given supplementary iron. If severe anaemia (haemoglobin concentration below 8.5 g/dl) is not detected until the last four weeks of pregnancy, blood transfusion is required to cover labour as the body has not enough time to manufacture sufficient circulating red cells to ward off the increase risk of blood loss at delivery. It is unsafe for any woman to approach labour with a haemoglobin concentration below 8.5 g/dl.

Sickle cell disease
Most adults have their haemoglobin in the A form which is virtually stable. Defective genes can alter the side chains of haemoglobin so that less stable haemoglobins are formed. Women with haemoglobin S are found in Africa and the West Indies and some other countries.
In pregnancy a woman with sickle cell disease is at high risk of complications. She deserves special antenatal supervision. Even in experienced hands the perinatal mortality can be four times that in a normal population and maternal mortality is also greatly increased. The management of cases involves high doses of folate, good hydration and packed red cell transfusions.

Folate deficiency
This condition is not very common as many women in Anguilla are taking folic acid prior to pregnancy mainly to prevent birth defects. Nowadays folate deficiency is usually detected during routine blood tests. Prevention is the best management of folic acid deficiency. Foods with a high folate content are recommended: beans, dark green leaf vegetables, legumes and fish.

What are the symptoms of anaemia?
Women with anaemia of pregnancy may not have obvious symptoms unless the cell counts are very low. The following are the most common symptoms of anaemia.
• Pale skin, lips, nails, palms of hands or underside of the eyelids
• Fatigue
• Vertigo or dizziness
• Laboured breathing
• Rapid heartbeat (tachycardia)
The symptoms of anaemia may resemble other conditions or medical problems. Always consult your physician for a diagnosis.

How is anaemia diagnosed?
Anaemia is usually discovered during a prenatal examination through a routine blood test for haemoglobin or haematocrit levels. Diagnostic procedures for anaemia may include additional blood tests and other evaluation procedures.
Treatment for anaemia:
Specific treatment for anaemia will be determined by your obstetrician based on:
• Your pregnancy, overall health and medical history
• Extent of the disease
• Your tolerance for specific medications, procedures or therapies
• Expectations for the course of the disease
• Your opinion or preference
Treatment depends on the type and severity of anaemia. Treatment for iron deficiency anaemia includes iron supplements. Some forms are time-released, while others must be taken several times each day. Taking iron with a citrus juice can help with the absorption into the body. Antacids may decrease absorption of iron. Iron supplements may cause nausea and cause stools to become dark greenish or black in colour. Constipation may also occur with iron supplements.

Conclusion
Anaemia in pregnancy is very common in Anguilla, but fortunately many pregnant women see their obstetrician early in their pregnancy and have blood tests so that the condition can be diagnosed and treated. Severe anaemia if not corrected prior to delivery can have many complications for both mother and the developing fetus. All pregnant women should see their health care provider early in their pregnancy so that anaemia and many other health conditions can be detected and treated.
Ask Your Doctor is a health education column and is not a substitute for medical advice from your physician. Dr. Brett Hodge is an obstetrician/gynaecologist and family doctor who has over twenty years in clinical practice. Dr. Hodge has a medical practice in the Johnson Building in The Valley.