According to scientific research in the U.S. eating chocolate, especially dark chocolate, during pregnancy is good for mother and baby.
The new research suggests it could help prevent a serious complication known as pre-eclampsia, where the blood pressure soars during pregnancy and excess protein is released into the urine.
Dr. Elizabeth Triche from Yale University says pre-eclampsia is a major pregnancy complication which has cardiovascular manifestations such as hypertension and affects up to eight percent of pregnancies.
The researchers say dark chocolate is particularly rich in a chemical called theobromine, which stimulates the heart, relaxes smooth muscle and dilates blood vessels; it has been used to treat chest pain, high blood pressure, and hardening of the arteries.
Dr. Triche and her colleagues wanted to see whether chocolate's suspected cardiovascular benefits also might help prevent pre-eclampsia.
To do this they studied 2,291 women who had delivered a single infant - they questioned them on how much chocolate they consumed in their first and third trimesters and also tested levels of theobromine in the infants' umbilical cord blood.
The research team found that women who consumed the most chocolate and those whose infants had the highest concentration of theobromine in their cord blood were the least likely to develop pre-eclampsia.
They found in fact that women with the highest cord blood theobromine were 69 percent less likely to develop the complication than those with the lowest; women who ate five or more servings of chocolate each week in their third trimester of pregnancy were 40 percent less likely to develop pre-eclampsia than those who ate chocolate less than once a week.
Dr. Triche who is the associate director at the Yale Center for Perinatal, Pediatric & Environmental Epidemiology, at Yale University, says theobromine could improve circulation within the placenta while blocking oxidative stress, or it could also be a stand-in for other beneficial chemicals found in chocolate.
The scientists say the other chemicals in chocolate include magnesium, which lowers hypertension, and flavanoids, which are potent antioxidants and the darker the chocolate is, the better it is.
The research is published in the May issue of Epidemiology.