Posted on Monday 23 March 2015
Dr Eugene Oteng-Ntim
A study into sickle cell disease (SCD) and its effect on pregnancy has found that women with a severe form of the disease are six times more likely to die during or after pregnancy. They also have an increased risk of stillbirth, high blood pressure, and premature birth.
Researchers from Guy’s and St Thomas’ are the first to confirm the health risks facing pregnant women with SCD in their study published today in Blood, the Journal of the American Society of Hematology. They are now hopeful that they can identify women with the highest risk of complications, to treat and manage their pregnancies safely and appropriately.
More than 300,000 babies worldwide are born each year with SCD. They produce abnormal haemoglobin, a protein that helps carry oxygen throughout the body. This defect causes the red blood cells to become rigid and sickle-shaped, blocking the flow of blood and oxygen to the body and causing intense pain and other complications.
Previous research has identified an association between SCD and high-risk pregnancy, however specialists have not previously been able to estimate a woman’s individual risk of specific complications, nor have they been able to identify groups of women at highest risk.
Dr Eugene Oteng-Ntim, consultant obstetrician at Guy’s and St Thomas’ and senior study author, says: “While we know that women with Sickle cell disease will have high-risk pregnancies, we have lacked the evidence that would allow us to confidently tell these women how likely they are to experience one complication instead of another.
“This makes it difficult for us to properly counsel our sickle cell patients and manage their expectations during their pregnancy.”
Dr Oteng-Ntim and research colleagues from King’s College London and the London School of Hygiene and Tropical Medicine examined 21 published observational studies comparing outcomes in women with and without SCD.
As a whole, the studies included 26,349 pregnant women with SCD and 26,151,746 pregnant women who shared attributes with the SCD population, such as ethnicity or location, but were otherwise healthy.
The team concluded that pregnant women with severe SCD living in a low-income country were at the highest risk for complications. When researchers compared these women to healthy pregnant women, they observed that women with the most severe form of SCD in both high and low income countries were six times more likely to die during or shortly after pregnancy.
Researchers also noted that women with severe SCD had an increased risk of high blood pressure during pregnancy (known as pre-eclampsia), stillbirth, preterm delivery, and delivering smaller-than-average babies.
Previous research has identified an association between SCD and high-risk pregnancy; however, specialists have not yet been able to estimate a woman’s individual risk for specific complications, nor have they been able to identify groups of women at highest risk.
While the analysis states that pregnant women with a milder or an unreported form of SCD were less likely than those with severe disease to experience complications, researchers note that these women remain at higher risk of most complications than healthy mothers.
“Until 20 years ago, women with SCD were not expected to live to child-bearing age. Because of recent medical advancements, our patients are receiving the treatment they need and living to an age where they are having their own children,” says Dr Oteng-Ntim.
“We finally have some robust data that doctors and obstetricians around the world can refer to, enabling them to give the best care they can to mothers and babies.
“This analysis is a first step toward improving universal care for all who suffer from this disease.”