Pregnancy and diabetes: general information

During pregnancy , significant changes in carbohydrate metabolism are observed. On the one hand, there is a tendency to hypoglycemia, on the other hand, insulin resistance. Blood amino acid levels are reduced, free fatty acids, ketone bodies and triglycerides are elevated. In the morning on an empty stomach, the glucose level in pregnant women is 0.8-1.1 mmol / L (15.20 mg%) lower than in non-pregnant women. If the fasting period exceeds 12 hours, the plasma glucose level drops to 2.2-2.5 mmol / L (40.45 mg%), and an increase in the levels of beta-hydroxybutyric and acetoacetic acids is 2-4 times higher than that of non-pregnant women. Therefore, during pregnancy, diabetic ketoacidosis develops even without severe hyperglycemia.    

Maternal hormones – insulin and glucagon – do not cross the placenta, while beta-hydroxybutyric and acetoacetic acids easily enter the bloodstream of the fetus and are used by the liver and brain as energy sources.        

The energy needs of the fetus are provided by maternal glucose. However, due to the development of insulin resistance, pregnancy diabetes may occur . Insulin resistance may be due to the action of a number of hormones, including progesterone , estrogen , prolactin, and placental lactogen .          

Insulin-dependent and non-insulin-dependent diabetes mellitus. In diabetes mellitus, perinatal mortality is increased (3-5% compared with 1-2% in healthy pregnant women) and the risk of fetal malformations (6-12% compared with 2-3%). Normalizing plasma glucose levels in early pregnancy reduces this risk. A woman should explain how important it is to control glucose levels and adjust the dose of insulin independently during pregnancy and throughout its duration. Fasting plasma glucose should be within normal limits, and 1 hour after a meal, no higher than 7.8 mmol / L (140 mg%). In addition, you need to regularly determine the level of glycosylated hemoglobin. In the II trimester, an ultrasound of the fetus should be performed, and to detect defects in the development of the nervous system – at the 20th week, determine the level of alpha-fetoprotein in the mother.  

With diabetic nephropathy, the prognosis for pregnancy is favorable: the fetus is viable in 90% of cases.  

As with other kidney diseases, in the second half of pregnancy, worsening of arterial hypertension, increased proteinuria, and decreased GFR are possible . These changes can be due to either preeclampsia or an increase in hydrostatic pressure in the glomerular capillaries. It is not proven that pregnancy exacerbates the course of diabetic nephropathy, however, such patients should be monitored by an obstetrician-gynecologist with experience in managing a complicated pregnancy, neonatologist, diabetologist and nephrologist.    

In cases where insulin secretion is insufficient to provide increased demand for this hormone during pregnancy, insulin resistance contributes to the development of diabetes in pregnant women. This disease occurs in 1-3% of pregnant women. Timely diagnosis is very important, since glucose penetrates the placenta, causing increased insulin secretion in the fetus. This is fraught with the development of fetal macrosomia, an increased risk of birth injury (may require a cesarean section), and hypoglycemia in the newborn.

There are no generally accepted criteria for diagnosing pregnant diabetes, nor are there uniform recommendations for examining pregnant women with normal fasting plasma glucose. Some obstetrician-gynecologists recommend an hourly oral glucose tolerance test with 50 g of glucose for all women at 24-28 weeks gestation. If the plasma glucose level after 1 h exceeds 7.8 mmol / L (140 mg%), a three-hour oral glucose tolerance test is prescribed with 100 g glucose.

Pregnant diabetes is diagnosed with two of the following three criteria:

– the plasma glucose level after 1 h exceeds 10.5 mmol / l (190 mg%),

– after 2 h – exceeds 9.2 mmol / l (165 mg%),

– through Zch – exceeds 8 mmodi / l (145 mg%).

However, the American College of Obstetricians and Gynecologists recommends performing an oral glucose tolerance test only if there are risk factors (over 30 years old, obesity, hypertension, glucosuria ; macrosomia, fetal malformations and a history of stillbirths).  

TREATMENT. Prescribe a diet. If the plasma glucose level on an empty stomach or after a meal remains elevated, insulin therapy is started. After childbirth, carbohydrate metabolism can normalize, but more than 30% of women with pregnant diabetes develop diabetes mellitus within 5 years.