If you are planning a pregnancy or are already pregnant, recent research indicates that it's in your baby's best interest to keep your blood sugar levels below 95 mg/dl, especially in the second and third trimesters of your pregnancy.
Researchers at the Institute of Obstetrics and Gynecology at the University of Florence, in Florence, Italy, studied 98 women with type 1 diabetes from the 12th week of pregnancy to the time they gave birth. They found that mothers whose blood sugar was regularly greater than 95 mg/dl in the second and third trimesters of pregnancy had an increased risk of bearing babies with macrosomia, a condition in which a baby is considered large.
Macrosomia can make giving birth difficult for you and raise the risk of injury to both you and your baby during labor. The condition most likely develops when blood sugar passes through the placenta and gives the developing baby high blood sugar levels in the womb. In turn, the baby's pancreas produces extra insulin, which makes the baby extra big. (The mother's insulin does not cross the placenta.) The extra insulin can put your baby at risk for low blood sugar at birth. Infants with high amounts of insulin at birth are at risk for being overweight as children and adults; thus they are at risk for type 2 diabetes later in life.
In the Italian study, researchers separated study participants into three groups. The mothers in the first group kept their blood sugar levels at or below 95 mg/dl during the second and third trimesters of pregnancy. The second group had average daily blood sugar values of more than 95 mg/dl during the second trimester, but equal to or less than 95 mg/dl during the third trimester. In the third group, mothers had average daily blood sugar levels of more than 95 mg/dl during both the second and third trimesters of pregnancy.