Pregnancy Week By Week

• Obesity (BMI over 30)
• A history of gestational diabetes in previous pregnancies
• A strong family history of diabetes.
• Sugar in urine
• Previous birthing of a baby that is bigger than 8 pounds, 13 ounces
• An unexplained stillbirth.
• A previous baby with a birth defect.
• High blood pressure.

However, many mothers with gestational diabetes have none of these risk factors.  

The digestive system breaks most food down into glucose, a type of sugar that enters the bloodstream and uses the insulin made by the pancreas to provide fuel for the body's cells.   Gestational diabetes causes glucose to stay in blood instead of moving into the cells and converting to energy.

Hormones during pregnancy make it hard for the body to process insulin quickly enough.  At the same time insulin performs a vital function.  In order to increase the quantities of insulin circulating in the body and fuelling its cells,   the pancreas increases its insulin production. A pregnant woman gets gestational diabetes when her pancreas can't keep up with the body's need for insulin, and  as a result,  the level of glucose in her blood soars to unhealthy heights.  

Most diabetic and pregnant mothers recover from the disease after the births of their babies.   However, gestational diabetes does increase their risk for Type II diabetes later in life.Therefore, during prenatal testing, doctors evaluate an expecting mother's blood sugar with glucose screening and tolerance tests.    If blood sugar levels are too high, they prescribe a low-sugar diet and plenty of exercise, as well as insulin shots when they are needed.  When they get appropriate care, most pregnant mothers with gestational diabetes go on to have healthy babies.  

Untreated gestational diabetes is dangerous, however, which makes prenatal care particularly important.   First,  it makes the mother twice as likely to develop preeclampsia (discussed in another article).  Secondly,  it can complicate delivery.  Excess glucose works its way into baby's blood and forces its immature pancreas to produce more insulin to process it.  An oversupply of insulin and blood sugar can make the baby put on extra weight, especially in the upper body, and then develop macrosomia, a condition in which either the baby outgrows the birth canal and gets stuck inside the uterus,   or its head enters the canal but the shoulders cannot fit. In this situation, called shoulder dystocia, the practitioner must ease the baby through the canal with gentle twists and turns and finally pull it out.  This process can break the baby's bones or damage its nerves. 

The damage heals without any permanent effects in 99 out of 100 babies, although in very rare cases, the baby may suffer brain damage because it doesn't get enough oxygen during delivery.  The procedure for delivering a broad-shouldered baby is actually more dangerous for the mother than the baby, because they may cause injuries to the vaginal area.   To avoid these risks, the practitioner may recommend a caesarian delivery instead.   

Gestational diabetes often has no symptoms, so most expecting mothers are given a glucose screening between weeks 24 and 28.  A diabetic mother is likely to be more thirsty, hungry, or tired than usual, and may have to urinate more frequently than she did before her pregnancy, but these are common, normal symptoms during any pregnancy.

However, one sign of diabetes is the presence of sugar in urine.   If the caregiver identifies this condition, or even if she knows that the mother is at high risk of the disease, she will recommend a diabetes screening test at the first prenatal visit and then again at 24 to 28 weeks if the result is negative.  A positive test result does not necessarily mean that the mother has gestational diabetes, but she will need to take a longer follow-up test for a diagnosis.  

If the mother is diagnosed with diabetes early in her pregnancy, she was probably diabetic before she conceived.  In this case, the provider usually orders a fetal echocardiogram (an ultrasound of the baby's heart), because the risk of birth defects, especially in the heart, are increased if the mother's blood sugar was high in the first eight weeks of pregnancy.    

If the mother has gestational diabetes, her practitioner is likely to monitor the baby more intensively during the last two to three months of pregnancy.  She will also ask the mother to pay close attention to the baby's movements during the third trimester, and contact her immediately if she senses less activity.   If the pregnancy is high risk or if the mother is taking insulin, she will also receive fetal heart monitoring, in the form of nonstress tests or periodic ultrasounds, and a biophysical profile around 32 weeks into the pregnancy.  If the baby is getting too big as early as the 29th to 32nd week, the practitioner will probably prescribe insulin, and either induce labor before the mother's due date, or recommend a C-section.  Despite all these potential complications, most mothers who are getting treatment for gestational diabetes give birth to normal babies.   

The baby may be born hypoglycemic  (with low blood sugar) because it has been compensating for the mother's high levels of glucose by making more insulin.  Hence, the delivery team tests the newborn baby's blood sugar.   If it's too low,  the baby needs to be fed immediately,  with breastfeeding, formula or sugar water.   It may also be at abnormally high risk for jaundice, polycythemia (an increase in the number of red cells in the blood), or hypocalcemia (low calcium in the blood).  It bears repeating, however, that  most babies of mothers with controlled gestational diabetes are born healthy and strong and will not suffer any complications from the mother's condition.

*This article is based on the information at http://diabetes.niddk.nih.gov, http://www.mayoclinic.com and ttp://www.babycenter.com