Blood disorder has little impact on pregnancy

Women with Hemoglobin SC disease, an inherited blood disorder, can expect relatively normal pregnancy outcomes, according to a report in BJOG: an International Journal of Obstetrics and Gynecology.

With hemoglobin SC disease, red blood cells assume odd shapes, resulting in their premature destruction and anemia. Hemoglobin SC disease is closely related to sickle cell disease but is usually milder. Both disorders primarily affect people of African descent.

The new finding runs counter to claims that pregnancy related-problems are more common with hemoglobin SC disease than with sickle cell disease, lead author Dr. Graham R. Serjeant, from the Sickle Cell Trust in Kingston, Jamaica, and colleagues note.

In the current study, 95 pregnancies in 43 hemoglobin SC disease patients were compared with 94 pregnancies in 52 sickle cell disease patients and 157 pregnancies in 68 healthy comparison subjects.

All of the subjects had been followed from birth to assess the age at which menstruation began. Despite having a delay in menstruation of nearly 1 year relative to healthy subjects, patients with hemoglobin SC disease had a similar age at first pregnancy.

Sickle cell anemia is an inherited disease in which the red blood cells, normally disc-shaped, become crescent shaped. As a result, they function abnormally and cause small blood clots. These clots give rise to recurrent painful episodes called "sickle cell pain crises."

Causes, incidence, and risk factors

Sickle cell anemia is caused by an abnormal type of hemoglobin (oxygen carrying molecule) called hemoglobin S. It is inherited as an autosomal recessive trait - that is, it occurs in someone who has inherited hemoglobin S from both parents.

Someone who inherits hemoglobin S from one parent and normal hemoglobin (A) from the other parent will have sickle cell trait. Approximately 8% of African Americans have sickle cell trait. Someone who inherits hemoglobin S from one parent and another type of abnormal hemoglobin from the other parent will have another form of sickle cell disease, such as sickle cell-b 0 thalassemia, hemoglobin SC disease, or sickle cell-b + thalassemia. Someone with sickle cell trait or these forms of sickle cell disease will usually have no symptoms or only mild ones. However, some of these conditions can cause symptoms similar to sickle cell anemia.

In terms of pregnancy outcomes, no significant differences were noted between hemoglobin SC disease patients and healthy subjects. Sickle cell disease patients, by contrast, had slightly more miscarriages, fewer live deliveries, and babies with lower birthweight compared with hemoglobin SC disease patients.