Gestational diabetes mellitus includes diabetes that existed before pregnancy and diabetes that occurred or was first detected after pregnancy. The latter is also known as gestational diabetes mellitus (GDM).
The incidence of GDM is reported to be between 1% and 14% worldwide, and most patients with GDM recover from abnormal glucose metabolism after delivery, but have an increased chance of developing diabetes in the future. The clinical course of pregnant women with diabetes mellitus is complex, and there is a greater risk to both mother and child. It must be taken seriously.
In the early and middle stages of pregnancy, the plasma glucose of pregnant women decreases with the progress of pregnancy, and the fasting glucose decreases by about 10%. In the middle and late pregnancy, the anti-insulin-like substances in pregnant women increase, so that the sensitivity of insulin in pregnant women decreases with the increase of gestational weeks. For pregnant women with limited insulin secretion, this physiological compensatory change cannot be maintained during pregnancy and leads to an increase in blood glucose, which aggravates the existing diabetes or causes GDM.
I. Effects of pregnancy on diabetes mellitus
1. Pregnancy can make the latent diabetes become obvious, make GDM occur in pregnant women without previous diabetes, and aggravate the condition of the original diabetic patients;
2, early pregnancy fasting blood sugar is lower, insulin dosage will be reduced compared to non-pregnant period. As pregnancy progresses, anti-insulin substances increase and insulin dosage needs to be increased continuously;
3. During labor and delivery, physical exertion is high and the amount of food is low, so if insulin dosage is not reduced in time, hypoglycemia may occur;
4. After delivery, as the placenta is expelled from the body, the anti-insulin substances secreted by the placenta disappear rapidly, and the insulin dosage should be reduced immediately, otherwise hypoglycemic shock is likely to occur;
5. Due to the complex changes of glucose metabolism during pregnancy, insulin dosage should be adjusted in time, otherwise hypoglycemia or hyperglycemia may occur, which may even lead to hypoglycemic coma and ketoacidosis in serious cases.
Second, the impact of diabetes on pregnancy
(A) The effect on pregnant women
1. High blood sugar can cause abnormal development or even death of the embryo, and the incidence of miscarriage is 15% to 30%. Diabetic women should consider pregnancy after normal blood sugar control. –
2, the incidence of hypertensive disease during pregnancy in pregnant women with diabetes is 3 to 5 times that of normal women, especially when diabetes is complicated by nephropathy, the incidence of hypertensive disease during pregnancy is up to 50% or more. Once a pregnant woman with diabetes is complicated by hypertensive disease in pregnancy, the condition is more difficult to control, which is extremely unfavorable to the mother and child.
3. Diabetic pregnant women have reduced resistance and are prone to co-infections, with urinary tract infections being the most common.
4. The incidence of excessive amniotic fluid is 10 times more than that of non-diabetic pregnant women. The reason may be related to fetal hyperglycemia and hyperosmolar diuresis that increase fetal urine excretion.
5. The incidence of large babies is significantly higher, and the chances of difficult delivery, birth canal injury and surgical delivery are higher.
6. Diabetic ketoacidosis is likely to occur. Diabetic ketoacidosis is more harmful to mother and child, not only is it the main cause of maternal death, but also has teratogenic effect when it occurs in early pregnancy, and easily leads to fetal distress and fetal death in utero when it occurs in the middle and late pregnancy.
(B) Effects on fetus
1. The incidence of giant fetus is as high as 25%-42%.
2. The incidence of fetal growth restriction is 2l%. It is seen in severe diabetes with vascular lesions, such as renal and retinal vascular lesions.
3. The incidence of preterm delivery is 10%-25%. The causes of preterm delivery include excessive amniotic fluid, hypertensive disorders during pregnancy, fetal distress and other serious complications that often require early termination of pregnancy.
4. The rate of fetal malformation is 6% to 8%, which is higher than that of non-diabetic pregnant women.
(C) Effects on the newborn
1.Increased incidence of neonatal respiratory distress syndrome High blood sugar stimulates increased insulin secretion in the fetus, resulting in hyperinsulinemia, reduced production and secretion of fetal lung surface active substances, and delayed fetal lung maturation.
2. Neonatal hypoglycemia. After the neonate leaves the maternal hyperglycemic environment, hyperinsulinemia still exists, and if sugar is not supplemented in time, hypoglycemia is prone to occur, which endangers the life of the neonate in serious cases.
III. Diagnosis
In patients with pre-existing diabetes, generally diabetes has been diagnosed before pregnancy or there are typical symptoms of diabetes, so it is easy to diagnose during pregnancy. However, pregnant women with GDM often have no obvious symptoms, and fasting blood sugar may sometimes be normal, which can easily lead to missed diagnosis and delayed treatment. The main points of diagnosis are as follows.
1, medical history and clinical manifestations The high-risk factors for GDM are as follows.
1)Family history of diabetes mellitus;
2) Positive urine glucose test several times during pregnancy
3)Age >30 years old, maternal weight >90kg;
4) Recurrent vulvovaginal pseudomarginal yeast disease;
5) history of recurrent spontaneous abortion, stillbirth or delivery of full-term RDS baby, history of delivery of huge baby or malformed baby;
6) Large fetus or excessive amniotic fluid in this pregnancy.
2. Laboratory tests
1) Blood glucose measurement: two or more times fasting blood glucose ≥ 5.8 mmol/L can be diagnosed as diabetes.
2) Glucose screening test: Most scholars now recommend screening for GDM at 24 to 28 weeks of gestation.
Method: 50g of glucose powder, dissolved in 200ml of water, taken within 5 minutes, followed by 1 hour measurement of blood glucose value ≥7.8mmol/L, is abnormal for glucose screening. If.
①Pregnant women with 50g of glucose screening ≥11.2mmol/L have a high probability of GDM.
②An abnormal fasting glucose check for pregnant women with abnormal glucose screening can be diagnosed as diabetes mellitus;
③Fasting glucose is normal, then further glucose tolerance test (OGTT) is performed.
3) OGTT: 75g glucose tolerance test is mostly used in China. The diagnostic criteria: ① 5.6mmol/L fasting, 10.3mmol/L at 1 hour, 8.6mmol/L at 2 hours, 6.7mmol/L at 3 hours, ② 2 or more of these items reach or exceed the normal value, can be diagnosed as gestational diabetes. ③Only 1 item is higher than the normal value, the diagnosis is abnormal glucose tolerance.
Staging of gestational diabetes mellitus
Staging (White’s classification) is based on the patient’s age at the onset of diabetes, the duration of the disease and the presence of vascular complications, which helps to determine the severity of the disease and its prognosis.
Grade A: Diabetes present or detected during pregnancy.
Grade A1: controlled by diet, fasting blood glucose <5.8 mmol/L and 2 hours postprandial blood glucose <6.7 mmol/L.
Grade A2: With dietary control, fasting blood glucose ≥5.8mmol/L and 2 hours postprandial blood glucose ≥6.7mmol/L.
Grade B: dominant diabetes mellitus, onset after 20 years of age, duration of disease <10 years.
Grade C: Onset at 10-19 years of age, or disease duration of 10-19 years.
Grade D: Onset before 10 years of age, or disease duration ≥20 years, or combined with simple retinopathy.
Grade F: diabetic nephropathy.
Grade R: Proliferative retinopathy or vitreous hemorrhage in the fundus.
Grade H: Coronary atherosclerotic heart disease.
Grade T: history of renal transplantation.
V. Treatment
(A) Indicators of whether a diabetic patient can be pregnant
The severity of diabetes mellitus should be determined before pregnancy, and once a woman with grade D, F or R diabetes mellitus becomes pregnant, the risk to the mother and child is greater. If the pregnancy has been terminated, it should be terminated as soon as possible.
If you have a mild organic lesion and good glycemic control, you can continue the pregnancy under active treatment and close supervision.
3.From the beginning of pregnancy, strictly control the blood glucose value with the assistance of internal medicine physician. Ensure that the blood glucose is in the normal range before conception, during pregnancy and during delivery.
(II) Management of pregnant women with abnormal glucose metabolism
1. Satisfactory criteria for glucose control during pregnancy.
① No obvious hunger in pregnant women;
②Maintain fasting blood sugar at 3.3mmol/L~5.6mmol/L;
③30 minutes before meal: 3.3mmol/L～5.8mmol/L; 2 hours after meal: 4.4mmol/L～6.7mmol/L; night: 4.4mmol/L～6.7mmol/L.
2., diet therapy: diabetic patients in pregnancy diet control is very important. Some pregnant women with gestational diabetes require only dietary control to maintain sugar in the normal range. Objectives.
①To ensure the necessary nutrition for mother and fetus;
②Maintain normal blood sugar level;
③Prevent ketosis;
④Maintain normal weight gain.
⑤ Pregnant women with diabetes in early pregnancy need the same number of calories as before pregnancy. After mid-pregnancy, calories increase by 3% to 8% per week. Among them, carbohydrates account for 40% to 50%, protein 20% to 30%. Fat 30% to 40%.
(6) Control the blood glucose value of 1 hour after meal below 8 mmol/L. In addition, daily supplementation of calcium folic acid 5mg and iron 15mg.
3.Medication: Sulfonylurea and biguanide hypoglycemic drugs can pass through the placenta and interfere with fetal metabolism, which has the risk of fetal death or malformation. Therefore, pregnant women should not be treated with oral hypoglycemic drugs.
1) For diabetes that cannot be controlled by diet therapy, insulin is the main treatment drug.
2)According to the characteristics of insulin action, there are insulin, low concentrate protein insulin and concentrate protein zinc insulin.
3) Insulin is used when there is an urgent need to control blood sugar, correct metabolic disorders and correct ketosis, and the method is subcutaneous injection. Insulin dosage varies greatly among individuals, and there is no uniform standard for reference. The principles of dosing are as follows.
(1) Generally start with a small dose and adjust it according to the condition, the progress of pregnancy and blood glucose value. Strive to control blood sugar at normal level.
(2) Insulin should be applied in early pregnancy to reduce insulin dosage according to blood glucose monitoring. With the increase of the pregnancy week, the production of anti-insulin substances in the body increases, and the insulin dosage should be increased continuously, which can be increased by 50% to 100% or even higher than the non-pregnant period.
(3) The peak period of insulin dosage is from 32 to 36 weeks of pregnancy, after which some patients’ insulin dosage decreases in the late pregnancy. Especially at night.
(4) During the puerperium, with the expulsion of placenta, the anti-insulin substance in the body decreases sharply. The amount of insulin required decreases significantly. The insulin dosage should be reduced to 1/3 to 1/2 of the amount before delivery, and the dosage should be adjusted according to the postpartum fasting glucose value.
(5) Insulin dosage should gradually return to pre-pregnancy level in 1 to 2 weeks after delivery.
4. Treatment of gestational diabetic ketoacidosis
1) While monitoring blood gas, blood glucose, electrolytes and giving corresponding treatment, it is recommended to apply small doses of regular insulin 0.1U/(Kg-h) intravenously.
2) Monitor blood glucose every 1 to 2 hours.
3)After blood glucose >13.9mmol/L, insulin should be added to saline intravenously, and blood glucose ≤13.9mmol/L. Start to add insulin to 5% glucose sodium chloride injection intravenously, and after the ketone body turns negative, it can be changed to subcutaneous injection.
5. Maternal and child monitoring during pregnancy Pregnancy reaction in early pregnancy may bring difficulties in blood glucose control, and blood glucose changes should be closely monitored and insulin dosage should be adjusted in time to prevent hypoglycemia.
1) Check once a week until the 10th week of pregnancy. In the middle of pregnancy, it should be checked once every 2 weeks. Generally, the insulin requirement starts to increase at 20 weeks of pregnancy, so timely adjustment is needed.
2)During this period, B-type ultrasound should be used to check fetal development and whether there are fetal malformations.
3) Monthly measurement of renal function and glycated hemoglobin level, as well as fundus examination should be performed.
4) Weekly check-ups should be performed after 32 weeks of gestation. Pay attention to blood pressure, edema and urine protein.
5)Pay attention to the monitoring of fetal development, fetal maturity, fetal placental function, etc. Early hospitalization if necessary.
6)Fetal lung maturity should be evaluated for those with possible early termination of pregnancy.
6. Timing of pregnancy termination The principle should be to postpone the timing of pregnancy termination as much as possible while strengthening maternal and child monitoring and controlling blood glucose.
1) If there is good glycemic control, no comorbidities in late pregnancy, and good intrauterine status of the fetus, the pregnancy should be terminated until the expected date of delivery (38-39 weeks).
2) If the glycemic control is unsatisfactory, accompanied by vascular lesions, combined with severe pre-eclampsia, serious infection, fetal growth restriction, fetal distress, the amniotic fluid should be extracted early to understand the maturation of fetal lung and inject dexamethasone to promote fetal lung maturation, and the pregnancy should be terminated immediately after the fetal lung maturation.
3) The intravenous application of dexamethasone for fetal lung maturation in diabetic pregnant women may cause a significant increase in blood glucose, so attention should be paid to adjusting the insulin dosage.
7.Method of delivery
1) Cesarean delivery Gestational combined diabetes is not an indication for cesarean delivery, but if there is a huge fetus, placental dysfunction, abnormal fetal position or other obstetric indications, cesarean delivery should be performed. In cases of diabetes mellitus complicated by vascular disease, early termination of pregnancy is often required and cesarean delivery is often chosen.
2) Vaginal delivery
(1) During vaginal delivery, blood glucose, urine glucose and urine ketone bodies should be monitored at all times so that blood glucose is not less than 5.6mmol/L (100mg/dl) to prevent hypoglycemia;
②Rehydration can also be given at the ratio of 1U insulin per 4g sugar.
③Contractions and fetal heart changes should be closely monitored during labor to avoid prolongation of labor;
④Delivery should be ended within 12 hours, and ketoacidosis is likely to occur in labor >16 hours.
8.Neonatal treatment
1) Cord blood should be taken from the newborn at birth to test blood sugar.
2) Regardless of the weight, the newborn should be treated as a premature baby.
3) Pay attention to heat preservation, oxygenation, early feeding of sugar water, early opening of milk.
4) Start regular drip 25% glucose solution 30 minutes after delivery.
5) Pay attention to the prevention of hypoglycemia, hypocalcemia, hyperbilirubinemia and RDS.
6) Most newborns return to normal blood glucose within 6 hours after birth. Full-term newborns with blood glucose <2.22mmol/L can be diagnosed as neonatal hypoglycemia.
7) Breastfeeding will not adversely affect the fetus in mothers receiving insulin therapy.
9. Postpartum treatment
1)After delivery, due to placental expulsion, the anti-insulin hormone drops rapidly, so the insulin dosage should be reduced to half of the original dosage within 24 hours after delivery, and reduced to 1/3 of the original dosage within 48 hours, and some patients even do not need to be treated with insulin at all.
2) GDM patients with obvious abnormal fasting glucose during pregnancy should have their fasting glucose rechecked as soon as possible after delivery, and those with abnormal glucose values should be diagnosed as diabetic combined pregnancy;
3) GDM patients with normal fasting glucose should undergo OGTT examination at 6 weeks to 12 weeks after delivery, if abnormal, it may be prenatal missed diabetes, and normal patients should also have their blood glucose checked every three years.
4) If you have another pregnancy, 60% to 70% of patients will have GDM again.