Highly obese women are at a sharply higher risk of a potentially fatal pregnancy complication compared to their normal-weight peers, especially if they gain a lot of weight while they're pregnant, new research shows.
About five percent of pregnant women develop high blood pressure and kidney problems, known as pre-eclampsia, usually after the 20th week of pregnancy. The condition carries serious risks for both mother and baby. While a high pre-pregnancy body mass index (BMI, a measure of weight in relation to height used to gauge whether a person is at a healthy weight) is a known risk factor for pre-eclampsia, there is little information on risks for the growing number of super-obese women. These are women with a BMI of at least 50, for example a woman 5 feet 5 inches tall weighing 300 pounds or more.
To examine how pre-eclampsia risk might be influenced by obesity type, the researchers looked at birth records from USA from 1989 to 2005, including more than 850,000 single live births. More than three-quarters of the women were at a normal weight before getting pregnant, while 21 percent were obese. Less than a half percent, or 3,001 women in all, were super-obese.
The overall risk of pre-eclampsia was 4.5 percent; it was about 3 percent for normal weight women, 9 percent for obese women, and 13 percent for super-obese women.
It was found that the risk of pre-eclampsia was tripled for the obese women (BMI of 30 or above) compared to the normal-weight women (BMI of 25 or less). The risk for the super-obese women was nearly fivefold greater. The faster a woman gained weight during pregnancy, the higher her risk of pre-eclampsia, no matter what her BMI. Super-obese women with high weight gain (over 0.7 kilograms, or about 1.5 pounds, per week) were 13 times as likely as normal-weight women with moderate weight gain (from 0.5 to 1.5 pounds a week) to develop pre-eclampsia.
The above findings indicate that BMI and rate of weight gain are synergistic risk factors that amplify the burden of pre-eclampsia among highly -obese women.
About five percent of pregnant women develop high blood pressure and kidney problems, known as pre-eclampsia, usually after the 20th week of pregnancy. The condition carries serious risks for both mother and baby. While a high pre-pregnancy body mass index (BMI, a measure of weight in relation to height used to gauge whether a person is at a healthy weight) is a known risk factor for pre-eclampsia, there is little information on risks for the growing number of super-obese women. These are women with a BMI of at least 50, for example a woman 5 feet 5 inches tall weighing 300 pounds or more.
To examine how pre-eclampsia risk might be influenced by obesity type, the researchers looked at birth records from USA from 1989 to 2005, including more than 850,000 single live births. More than three-quarters of the women were at a normal weight before getting pregnant, while 21 percent were obese. Less than a half percent, or 3,001 women in all, were super-obese.
The overall risk of pre-eclampsia was 4.5 percent; it was about 3 percent for normal weight women, 9 percent for obese women, and 13 percent for super-obese women.
It was found that the risk of pre-eclampsia was tripled for the obese women (BMI of 30 or above) compared to the normal-weight women (BMI of 25 or less). The risk for the super-obese women was nearly fivefold greater. The faster a woman gained weight during pregnancy, the higher her risk of pre-eclampsia, no matter what her BMI. Super-obese women with high weight gain (over 0.7 kilograms, or about 1.5 pounds, per week) were 13 times as likely as normal-weight women with moderate weight gain (from 0.5 to 1.5 pounds a week) to develop pre-eclampsia.
The above findings indicate that BMI and rate of weight gain are synergistic risk factors that amplify the burden of pre-eclampsia among highly -obese women.