Pregnancy in women with diabetes
Author: Dr Sorin Ioacara | Last update: November 9th, 2020
Discover here: Metabolic changes | Increased blood sugar | Low blood sugar | Retinopathy | Chronic kidney disease | Cardiovascular complications | Thyroid problems | 1st trimester | 2nd trimester | 3rd trimester | The birth | Postpartum period | Pregnancy or gestational diabetes | The effects of diabetes on pregnancy
Pregnancy in a woman with diabetes can become a dangerous situation for both mother and child. Pregnancy preparation is essential in the presence of diabetes. It takes two glycosylated hemoglobin values below 7% (53 mmol/mol), measured three months apart to start conception safely. Unfortunately, pregnancy in adolescents with diabetes always occurs unexpectedly, i.e. without prior preparation.
We will further discuss the metabolic changes that occur in pregnancy. Then, we will see what are the principles of diabetes care during pregnancy and what gestational diabetes is. Finally, we will study how diabetes influences pregnancy and how pregnancy influences diabetes.
Metabolic changes in pregnancy
During pregnancy, several metabolic changes occur in the mother’s body. They have the role of ensuring optimal fetal growth. Maternal blood glucose is essential for the fetus. The mother’s body sacrifices itself and gives up glucose utilization so that it will be sufficient for the fetus. After two months of pregnancy, fasting blood sugar drops significantly and might not stop falling until the end of the 4th month of pregnancy.
Physiological resistance to the action of insulin
For enough glucose to reach the growing fetus, insulin resistance will appear in the mother’s body. In this way, the insulin will no longer be able to introduce glucose into the mother’s cells to be consumed here. As a result, blood sugar after meals will increase more than before pregnancy. The reason is that insulin will no longer cope with the demand, having its effect partially blocked.
This additional increase in maternal blood sugar after meals is beneficial for the fetus. It will thus have the ideal fuel for its growth. The mother’s body increases the liver’s production of glucose so that it will be readily available in between meals.
Insulin resistance in the liver is responsible for the increase in glucose production. Note that insulin typically reduces glucose production in the liver.
The mother’s pancreas feels that the insulin it secretes does not work as it did before pregnancy. Therefore, he will decide to secrete more insulin. The goal is to overcome pregnancy-induced insulin resistance in this way.
This resistance to insulin increases significantly in the second half of pregnancy. At birth, the mother has more insulin-secreting cells in her pancreas. The increase is not only in their number, but also the volume of each cell.
Adipose tissue in pregnancy
In the first part of pregnancy, the mother’s body will gather as much fat as it can. In the second part of pregnancy, it will have to decrease the glucose burning, which transfers to the fetus. Consequently, the mother’s body will switch to the preferential burning of previously accumulated fats.
Typically, insulin opposes the release of fat from stores. This opposition is no longer effective in the second half of pregnancy due to insulin resistance. All these changes in the mother’s metabolism are natural. They are especially useful for expected fetal growth.
Metabolic changes during pregnancy in women without diabetes are also present in women with diabetes. These are associated with several features related to the presence of diabetes. Pregnancy preparation in a diabetic patient is critical.
Metabolic changes in pregnancy with type 1 diabetes
In type 1 diabetes, insulin requirements will decrease slightly in the first trimester. Subsequently, insulin requirements will increase to higher than before pregnancy. The reason for this increase is the fact that a state of resistance to the action of insulin gradually appears in the whole maternal organism.
Due to the preferential consumption of lipids in the second half of pregnancy, the risk of excessive production of ketone bodies increases significantly. Consequently, the susceptibility to diabetic ketoacidosis also increases.
Diabetic ketoacidosis can occur at moderately elevated blood glucose levels, such as 360 mg/dl (20 mmol/l). Sometimes, ketoacidosis occurs completely unexpectedly in a teenage or young woman previously known to have type 2 diabetes.
As we will see below, caring for a woman with diabetes during pregnancy can be exceedingly complicated.
Metabolic changes in pregnancy with type 2 diabetes
In type 2 diabetes, there is already a state of resistance to the action of insulin even before pregnancy. This insulin resistance will get worse during pregnancy. It would be best if you didn’t use diabetes pills in pregnancy. Therefore, you should use insulin if diet alone is no longer enough for maintaining the metabolic control.
If insulin is needed instead of pills, you should use multiple daily doses. The total amount per day can be relatively high. It can exceed even those prescribed in type 1 diabetes.
Increased blood sugar during pregnancy
Pregnancy has multiple consequences for pre-existing or early diabetes. There are sometimes women with ordinary blood glucose before pregnancy, but at the upper limit of normal. Sometimes these blood sugar levels can be in the prediabetes area before pregnancy. These women may have a significant increase in blood sugar during pregnancy, with a consequent diagnosis of gestational diabetes.
The discovery of diabetes for the first time in the 2nd or 3rd trimester of pregnancy gives it the name of gestational (or pregnancy) diabetes. However, the diagnosis must change after birth.
In type 1 diabetes, you may improve the glycemic control by increasing the frequency of glycemic self-monitoring. Patients use glucometers and continuous blood glucose monitoring sensors. The obtained glucose values translates into constant adjustment of insulin doses in basal-bolus therapy.
In type 2 diabetes, the vast majority of women will need temporary insulin treatment during pregnancy. The main reason is that you cannot use oral antidiabetic drugs in pregnancy. Pregnancy care with gestational diabetes involves diet in the vast majority of cases and insulin in the minority.
Insulin doses in pregnancy
You must prepare the pregnancy carefully. Its appearance should not surprise neither the woman nor the doctor. Often, immediately after becoming pregnant, the woman receives information that there will be an increase in blood sugar. There is almost always a recommendation to increase insulin doses. This recommendation is not always correct.
If the glycemic control is low at the time of conception, it must indeed be improved. By default, insulin doses will be increased or multiplied. However, treatment intensity must rise slowly. A sudden drop in average blood sugar is associated with a worsening of pre-pregnancy diabetes complications. A relevant example would be retinopathy. Hence the importance of obtaining reasonable glycemic control before pregnancy.
Treatment with two doses of premixed insulin is significantly worst compared to the basal-bolus approach. Basal-bolus insulin therapy involves the presence of an insulin that provides the basal insulin level for 24 hours and another insulin, administered at meals. Prandial insulin provides the insulin needed to fight blood sugar rise after a meal.
Intensified insulin treatment in pregnancy
Basal-bolus insulin treatment using external injections generally provides the same performance as the insulin pump. Two conditions still exist, the proper training of the patient and the possibility of self-monitoring. In the presence of continuous blood glucose monitoring sensors, however, the insulin pump is a superior option.
In the case of treatment with 4-5 insulin doses, there must be careful and continuous dose adjustment. You should always consider physical effort, food intake and blood sugar.
Adjusting insulin doses during pregnancy
Pregnancy care with diabetes involves continuous adjustment of insulin doses. For basal insulin at bedtime, you may increase it by 2U if the morning blood glucose exceeds 110 mg/dl (6.1 mmol/l) for three consecutive days. You may reduce the dose by 2U if there has been hypoglycaemia overnight or morning blood glucose falls below 90 mg/dl (5 mmol/l).
The doses of insulin given at meals are best adjusted according to the 1h glycemia. Alternatively, you use blood sugar values measured at 2h or before the next meal, but with slightly inferior results.
The blood glucose target at 1h after a meal is below 140 mg/dl (7.8 mmol/l). These blood sugar targets can be relaxed provided that obtaining them is accompanied by the frequent occurrence of hypoglycemia.
Decreased blood sugar in pregnancy
If at the time of conception, there is reasonable glycemic control, then both blood glucose and insulin requirements decrease in the first trimester of pregnancy. This decrease is due to the physiological (normal) increase in the body’s sensitivity to the action of insulin. Therefore, maintaining or increasing insulin doses will inevitably be associated with hypoglycaemia.
Glucagon and catecholamines are the body’s antidote to hypoglycemia. The hormonal counter-regulatory response to hypoglycemia does not work correctly during this period. These hypoglycemias tend to occur at night and are difficult to notice. Hence, they often leads to severe hypoglycaemia. Severe hypoglycemia means that another person is the one who solves the problem because the affected woman is no longer able to take care of herself.
The risk of hypoglycemia is higher in type 1 diabetes, where 66% of women are affected, compared to type 2, where 20% of women are at risk. If the hypoglycemias constantly repeat, in addition to the usual preventive measures, it is suitable for the woman in question to avoid driving for 3-4 months.
In women with type 1 diabetes, the family should be instructed on how to administer glucagon. It can be a life-saving solution for severe hypoglycemia.
The risk of hypoglycaemia decreases significantly in the second half of pregnancy, after week 20. Women with diabetes should perform glycemic self-monitoring during pregnancy at least four times a day. This frequent testing might be both expensive and slightly unpleasant for the expectant mother. However, the benefits are much more significant.
Pregnancy care with diabetes requires additional glycemic testing in case of hypoglycemia. Occasional blood glucose testing at three o’clock at night helps prevent nocturnal hypoglycemia. This extra glucose test is even more critical in the first trimester of pregnancy.
Antidiabetic treatment options to avoid in pregnancy
During pregnancy, several therapeutic methods are no longer available for safety reasons. However, evidence is accumulating quickly, and it is very likely that soon some new products will become available. Drugs that you cannot use during pregnancy at this moment include metformin, sulfonylureas, SGLT2 inhibitors and GLP1 analogues.
Pregnancy and diabetic retinopathy
Usually, in the third trimester of pregnancy, there is a decrease in retinal blood supply. This decrease is a consequence of a reduction in the diameter of the retinal arteries by local contraction. In pregnancy that progresses in a woman with diabetes, this phenomenon is much more pronounced. The blood of people with diabetes tends to clot much faster. This tendency is in contrast to the trend of skin wounds to heal over a more extended period.
Reduced blood flow to the retina can lead to a lack of local oxygenation. Consequently, pre-existing retinopathy lesions may worsen during pregnancy. The worsening of diabetic retinopathy occurs mostly in women with poor metabolic control before pregnancy. An additional risk factor is a sudden drop in blood sugar during pregnancy by intensifying the treatment. Fortunately, the worsening of retinopathy rarely persists on the long-term after birth.
The more advanced the retinopathy is before pregnancy, the greater the risk that it will progress during pregnancy. Women with proliferative retinopathy should do any required laser therapy before pregnancy. The goal is to prevent the progression of retinopathy during pregnancy.
Blood pressure and metabolic control reduce the risk of progression of retinopathy. It would be best if you had a strict metabolic control before pregnancy. The reason is that a sudden drop in mean blood sugar levels after the discovery of pregnancy may contribute to the temporary worsening of retinopathy.
Pregnancy and chronic diabetic kidney disease
Fortunately, pregnancy has no adverse effects on chronic diabetic kidney disease (nephropathy). If the kidney damage is already moderate, a transient worsening may occur during pregnancy. After birth, there will be a return to pre-pregnancy values. Women with a typical urinary albumin/creatinine ratio or only in the range of microalbuminuria will not have a transient worsening during pregnancy. The rate of albumin (protein) elimination in the urine is an essential indicator of kidney damage in diabetes.
Increased urinary excretion of albumin
A slight elimination of albumin in the urine, in the range of microalbuminuria (30-300 mg/g) will not worsen during pregnancy. It is, however, associated with an increased risk of pregnancy-induced hypertension, preeclampsia and premature birth.
A slightly higher elimination of albumin in the urine (macroalbuminuria), is associated with a higher risk for these complications. Therefore, you should maintain a rigorous metabolic and blood pressure control to reduce the risk of complications.
The presence of diabetic nephropathy in the stage of macroalbuminuria (urinary albumin/creatinine ratio > 300 mg/g) leads to a significant reduction in maternal life expectancy. Hence, the future mother should evaluate the psychological aspects resulting from the fact that most mothers with chronic kidney disease will not survive long enough to be with the child until the age of 18 years. Many of those who do survive that long will need dialysis in the last years of life.
Women with diabetes who have had a kidney transplant may become pregnant. There is, in this case, a slightly higher risk for complications associated with diabetic nephropathy. With professional care, the mother can complete all pregnancy-associated tasks successfully.
When, in addition to urinary excretion of albumin, there is a reduction in the renal function, the number of pregnancy complications increases even more. These complications may include low birth weight for gestational age and neonatal hypoglycemia.
Pregnancy and cardiovascular complications
The risk of ischemic heart disease in pregnant women increases with obesity, older age and diabetes. Ischemic heart disease is the main reason for deaths of cardiovascular origin during pregnancy. Women with type 1 diabetes aged 35-45 have a 15 times higher risk of heart attack or stroke compared to the same women in the general population without diabetes. For type 2 diabetes, the risk of a heart attack is five times higher.
It would be best if you do a careful assessment and cardiac care routinely to reduce these risks. Hypertension and pre-eclampsia should be sought and treated with maximum attention. Try to eliminate excess weight before conception. Besides, you should avoid gaining too much weight during pregnancy.
Pregnancy and thyroid function in diabetes
Women with type 1 diabetes have an increased risk for other autoimmune diseases, including autoimmune thyroid disease and celiac disease. Maternal hypothyroidism, even mild, can have adverse consequences on the fetus, especially in terms of neurological development. You should monitor the thyroid function carefully during pregnancy. It would be best to do thyroid tests repeatedly, every 3-4 weeks. The dose of levothyroxine will be adjusted monthly, depending on the results.
Iron supplements, if prescribed to the mother, should be taken two hours before or after the administration of thyroid hormones because they can inhibit their absorption. You should very closely follow the hyperthyroidism in Graves’ disease. The reason is that antibodies that stimulate the mother’s thyroid to secrete excess hormones can cross the placenta. Thus, they can do the same to the child. Fetal or neonatal (transient) hyperthyroidism may occur.
Pregnancy care with diabetes in the first trimester
Women with diabetes who discover a pregnancy should immediately see a gynaecologist (obstetrician). The next urgent consult should be with their diabetologist. Under no circumstances should you wait for the previously scheduled diabetes consultation. You need a new appointment as soon as possible. It would be best if you do the mandatory pre-pregnancy investigations as quickly as possible if you didn’t prepare the pregnancy.
You should carefully evaluate the microvascular (retinopathy, nephropathy, neuropathy) and cardiovascular complications.
Evaluation of concomitant medication
At the first visit to the diabetologist after becoming pregnant, the woman will bring an exact list of the medications she is taking. Included here are the supplements or those that she considers to be unimportant. Drugs banned in pregnancy are much more numerous than those allowed. Your doctor can advise you in this regard.
Pay close attention to folic acid (5 mg/day), and do not miss your daily dose. Ideally, it would be best if you started the folic acid intake before conception.
Evaluation of antidiabetic treatment
Pregnancy care with diabetes necessarily involves reviewing antidiabetic treatment. Most patients with type 2 diabetes will need insulin treatment during pregnancy.
You need to update your knowledge on diet. Carbohydrates recommendations usually are in the range of 160-200g per day. Of these, 30g should be in the form of dietary fibres. The rest of them should have a low glycemic index (slow absorption) as much as possible. You should pay close attention to the risk of hypoglycemia in the first trimester.
Contrary to usual expectations, the calorie requirement in pregnancy increases very little, with only 100 kcal in the first trimester and 300 kcal in the last trimester. Weight gain throughout pregnancy should not exceed 13 kg.
The physical effort will be made within the limit of individual tolerance, with at least 30 minutes a day of moderate physical exertion. Blood glucose levels should be brought as close to normal as possible, without suddenly lowering them. A sudden drop in blood sugar could worsen the condition of microvascular complications.
Pregnancy care with diabetes in the 2nd trimester
Insulin sensitivity begins to decrease, starting with the 2nd trimester of pregnancy (weeks 13 – 27). For this reason, the need for insulin begins to increase gradually. The first thing to raise is the dose of basal insulin. You may want to titrate to the maximum tolerated carefully, without overnight hypoglycaemia or morning blood glucose <90mg/dl (5 mmol/l). The good news during this period is that the risk of hypoglycemia decreases a lot. Thus, you may increase insulin doses more easily.
Weight gain is minimal in the 1st trimester (2 Kg). It inevitably accelerates in the 2nd trimester. Be very careful with your diet and don’t forget that in the 3rd trimester you will have the most significant weight gain. The target of 13 Kg maximum weight gain in pregnancy is not easy to achieve.
Reassessment of complications associated with diabetes
At week 16, your doctor will recommend a new fundus examination if you already have retinopathy, including for those with recently discovered retinal damage in the first trimester. You should closely monitor the blood pressure if you have high blood pressure or abnormal urinary albumin excretion (micro or macroalbuminuria). Blood pressure may increase during pregnancy.
Treatment of high blood pressure in pregnancy is not straightforward (e.g. with alpha methyldopa). It would help if you started the therapy as soon as possible after diagnosis.
Women who are in their first pregnancy can typically feel the fetal movements at week 20. If you had a pregnancy before, you might feel them from week 18. In some cases, you may feel these movements even at week 16.
Gestational diabetes testing
During week 24-28, women without known diabetes should perform the glucose tolerance test. This test consists of drinking 75 g of glucose dissolved in water, with the collection of three glycemia (basal, 1h and 2h). Your doctor should interpret the results according to the new criteria derived from the HAPO study. The diagnosis of gestational diabetes is increasingly common. Therefore, you should pay attention to this issue.
Pregnancy care with diabetes in the 3rd trimester
Women with gestational diabetes have an additional pregnancy-associated risk due to diabetes. Blood pressure should be monitored frequently, especially in women with abnormal urinary protein excretion. Preeclampsia is a complication of pregnancy that occurs more regularly in the presence of diabetes. If the mother has retinopathy, she must perform a new fundus examination in the 3rd trimester.
Tracking the child’s growth rate
In the 3rd trimester, there is a critical weight gain of both the mother and the fetus. Frequently, children from mothers with diabetes weight over 4000g at birth. They are called macrosomes. Their large size can prevent a natural birth and sometimes impose a cesarean section.
Unbalanced diabetes increases the risk of giving birth to a macrosome fetus. Pay close attention to glycemic control. In the 3rd trimester, it is necessary to check the fetal growth rate and the amniotic fluid by serial ultrasounds.
Birth in a woman with diabetes
Often, the child in a mother with diabetes is more massive than expected for gestational age. He may suffer shoulder injuries during childbirth. As a consequence, natural birth is often not possible. Indeed, cesarean delivery is much more common in the presence of diabetes. Poor glycemic control in the last trimester leads to an accelerated weight gain of the child. For these reasons, you may have an induced premature birth. If the situation requires it, premature birth takes place usually after 38 weeks of gestation. However, up to a third of women with diabetes will have a premature birth before 37 weeks.
Risk factors for preterm birth are:
- high blood sugar before birth
If an ultrasound evaluation of the baby’s weight and size shows that the chances of a natural birth without complications are low, you may get a cesarean section.
Insufficient development of the lungs
Women at risk of preterm birth will receive corticosteroids in the form of two intramuscular injections on two consecutive days. The purpose of these injections is to stimulate the development of the baby’s lungs. Administered corticosteroids will increase insulin requirements. The mother should monitor her blood sugar more often during this period. If necessary, increase the doses of insulin, especially the basal one.
Hypoglycemia and glycemic targets
Poor glycemic control during birth (starting with contractions) can lead to hypoglycemia in the baby immediately after birth. To have reasonable glycemic control during childbirth, women with type 1 diabetes will receive an insulin infusion. The doctor will closely monitor the blood glucose levels for appropriate adjustments in intravenous insulin debit.
The goal is to maintain blood glucose levels below 144 mg/dl (8 mmol/l). If you can obtain an excellent metabolic control during late pregnancy by diet alone, most often there will be no need for insulin treatment during birth. Blood glucose should be checked carefully in this case, as well.
Immediately after birth, the need for insulin decreases a lot, reaching even lower values than before she became pregnant. You should pay attention to the risk of hypoglycaemia if you don’t lower your insulin doses significantly after birth. Hourly glycemic self-monitoring plays an essential role in this situation.
Postpartum care for women with diabetes
Immediately after birth, the need for insulin decreases suddenly. In the absence of insulin dose adjustment according to blood glucose levels determined by self-monitoring, hypoglycemia may occur. Any woman with diabetes who has given birth should be encouraged to breastfeed. There are a lot of benefits for both the mother and baby after breastfeeding. All these benefits are still there in women with diabetes. In women with type 1 diabetes, there is a risk of hypoglycaemia during breastfeeding. For this reason, they should take a small snack before or during breastfeeding. In the absence of insulin treatment, the risk of hypoglycaemia is low after birth.
Pay attention to the need to reduce the insulin doses after birth. Total daily insulin requirement can reach levels even lower than before the pregnancy. Women who do not need insulin may use a diet-only approach to keep their blood sugar levels in check.
Antidiabetic drugs after birth
Regarding diabetes pills, they are still formally contraindicated. Metformin and glibenclamide are the only ones not significantly found in the breast milk. For this reason, they might receive approval to be used officially during breastfeeding sometimes in the future.
What happens to gestational diabetes after birth
In women with diabetes discovered during pregnancy, the diagnosis of gestational diabetes stops at birth. There are two options:
- Persistence of glycemia in the diabetes range
- Return to normal blood glucose levels
In the case of persistent diabetes after birth, it is most often type 2, but there will also be some cases of type 1 diabetes, with insulin required for survival.
Gestational (pregnancy) diabetes has a dedicated chapter. Gestational diabetes is also called pregnancy diabetes. Any blood glucose higher than usual, found starting with the 2nd trimester of pregnancy diagnoses gestational diabetes. Although questionable, diabetes that occurred during the 2nd and 3rd trimesters of pregnancy, given that it previously existed during a previous pregnancy, will also be called gestational diabetes.
The effect of diabetes on pregnancy
The impact of diabetes on pregnancy has a dedicated chapter. Diabetes can increase the number of red blood cells through local hypoxia and hyperinsulinemia. Respiratory distress syndrome (the newborn suffocates) occurs more often due to the association of premature birth and cesarean section. Diabetes has adverse effects on pregnancy just as pregnancy has negative effects on diabetes.