Pregnancy with diabetes

Written by: 
Dr Paola Accolai

Diabetes and pregnancy have a significant impact on one another. A woman's pre-existing diabetes can affect her pregnancy, or 'gestationIn pregnancy, the time from conception to birth.', while, the other way round, a woman who does not have diabetes can develop diabetes during pregnancy.

Gestational diabetes

Gestational diabetes is defined as a reduced ability of the body to handle glucoseA simple sugar that is an important source of energy in the body. (bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. sugar) that is first seen during pregnancy.[1]

High levels of glucoseA simple sugar that is an important source of energy in the body. in the body usually stimulate the production of insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. by the pancreas. Insulin is a hormoneA substance produced by a gland in one part of the body and carried by the blood to the organs or tissues where it has an effect. that acts to lower the levels of glucoseA simple sugar that is an important source of energy in the body. in the body, for example, by bringing about the conversion of glucoseA simple sugar that is an important source of energy in the body. into fatOne of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body..

As such, gestational diabetesAny level of glucose intolerance first detected during pregnancy. (or, in fact, any type of diabetes mellitusDisordered energy metabolism and high levels of glucose in the blood owing to a lack of insulin, or poor response of the body to insulin.) may result if inadequate insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. is being produced, or if the body is resistantA microbe, such as a type of bacteria, that is able to resist the effects of antibiotics or other drugs. to the actions of insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. - this is called 'insulin resistanceA reduced response of the body to the hormone insulin, resulting in raised blood glucose levels.'. In fact, it seems that both of these factors are important.

Although gestational diabetesAny level of glucose intolerance first detected during pregnancy. usually resolves after the birth, women who have had gestational diabetesAny level of glucose intolerance first detected during pregnancy. have a higher risk of developing diabetes later on.[2,3,4]

What causes gestational diabetes?

Insulin resistanceThe ability of a microbe, such as a type of bacteria, to resist the effects of antibiotics or other drugs. is a normal feature of any pregnancy. It seems to be caused by placental hormones, although increased fatty tissue may also have a role. Women often become more sensitive to the actions of insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. again once the placentaThe organ that nourishes the embryo during pregnancy and also eliminates waste. has been delivered.[2,4]

The pancreas usually secretes more insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. during pregnancy, to compensate for the degree of insulin resistanceA reduced response of the body to the hormone insulin, resulting in raised blood glucose levels. that happens as a matter of course. But it is thought that women who develop gestational diabetesAny level of glucose intolerance first detected during pregnancy. might already have had a degree of insulin resistanceA reduced response of the body to the hormone insulin, resulting in raised blood glucose levels. before they became pregnant. In addition, the pancreas is sometimes not able to produce insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. as efficiently. Because of this, these women are not able to produce enough insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. to compensate for the increased insulin resistanceA reduced response of the body to the hormone insulin, resulting in raised blood glucose levels. of pregnancy.[4]

Gestational diabetes is most often seen in the third trimesterA period of three months often used to describe the stage of pregnancy, where there are three - first, second and third trimesters. (the last three months of pregnancy), as the levels of placental hormones rise. Some centres screen for gestational diabetesAny level of glucose intolerance first detected during pregnancy.; it may be helpful to find out if this is standard practice in your country.[3]

The effects of diabetes on pregnancy

The health risks of diabetes for a pregnant woman increase the higher her glucoseA simple sugar that is an important source of energy in the body. levels are. The best state for the fetusAn unborn child from eight weeks of development onwards. is when the woman's glucoseA simple sugar that is an important source of energy in the body. levels are normal - not too high but, equally, not too low.[5]

The main effects of diabetes on pregnancy include an increased risk of the following: [5,6]

  • High birth weight
  • Congenital malformation and miscarriageThe spontaneous loss of pregnancy.
  • Pre-eclampsia
  • Neonatal hypoglycaemiaLow blood glucose levels.
  • Long-term health issues.

High birth weight

High levels of glucoseA simple sugar that is an important source of energy in the body. in a pregnant woman's bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. can cross the placentaThe organ that nourishes the embryo during pregnancy and also eliminates waste. to the fetusAn unborn child from eight weeks of development onwards., but insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. cannot do so. The resulting high fetal glucoseA simple sugar that is an important source of energy in the body. levels lead to increased insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. production by the fetusAn unborn child from eight weeks of development onwards. (once the pancreas has formed, that is).[3]

Insulin has a number of effects that increase the size of the fetusAn unborn child from eight weeks of development onwards., making a high birth weight more likely. A birth weight greater than 4,000g (9lb) is known as macrosomiaAbnormally large size. In the newborn baby, a birth weight greater than 4,000g.. Macrosomia becomes more likely with higher maternal glucoseA simple sugar that is an important source of energy in the body. levels.[3]

Birth injury to both baby and mother is more likely with macrosomiaAbnormally large size. In the newborn baby, a birth weight greater than 4,000g., and more of these babies are born by Caesarean section.[3,4,6]

Congenital malformation and miscarriage

If bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. sugar is poorly controlled in the first 42 days of pregnancy, congenitalAny condition present since birth. malformations and early miscarriageThe spontaneous loss of pregnancy. may occur, although this is rare. The organs of the fetusAn unborn child from eight weeks of development onwards. are being formed during this first 6 weeks, which makes pre-conceptionThe fertilisation of an ovum by a sperm cell: the start of pregnancy. advice all the more important for women with diabetes.[3,6]

Pre-eclampsia

Pre-eclampsia is a condition that occurs during pregnancy that is associated with high bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. pressure, fluid retention and protein loss in the urine. The chances of a woman developing pre-eclampsiaA condition of pregnancy associated with high blood pressure and protein in the urine (proteinuria). are much greater if she has type 1 diabetes. This risk is even higher in women with diabetes who also have kidney problems.[1,6]

Neonatal hypoglycaemia

Some newborn babies of women with diabetes have low bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels. This is because the baby is no longer getting high bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels from its mother, yet still has the high levels of insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels.. If treatment is needed, a glucoseA simple sugar that is an important source of energy in the body. infusion is given after birth.[3,6]

Long-term health issues

Babies born to women with gestational diabetesAny level of glucose intolerance first detected during pregnancy. have a higher risk of obesityExcess accumulation of fat in the body. and diabetes in the long term.[4]

This may not be solely due to geneticRelating to the genes, the basic units of genetic material. factors; exposure of the fetusAn unborn child from eight weeks of development onwards. to high glucoseA simple sugar that is an important source of energy in the body. levels may also promote abnormal glucoseA simple sugar that is an important source of energy in the body. metabolismThe chemical reactions necessary to sustain life.. Careful control of glucoseA simple sugar that is an important source of energy in the body. levels both before conceptionThe fertilisation of an ovum by a sperm cell: the start of pregnancy. and throughout pregnancy may reduce the risk.[7,8]

The effects of pregnancy on diabetes

This section will outline the effects pregnancy can have on a woman's pre-existing diabetes, which include an increased risk of:

  • Poor glucoseA simple sugar that is an important source of energy in the body. control and a greater need for insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels.
  • Hypoglycaemia
  • Worsening of diabetic complications.

Poor glucose control and a greater need for insulin

The insulin resistanceA reduced response of the body to the hormone insulin, resulting in raised blood glucose levels. brought about by placental hormones and other factors makes dietary considerations all the more important for women with diabetes who become pregnant, and frequent insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. adjustments may be needed.[5] In fact, the need for insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. is sometimes tripled with pregnancy.[6]

Hypoglycaemia

During pregnancy, women who have diabetes have a greater risk of severe hypoglycaemiaLow blood glucose levels., and this may come on suddenly.[5] This is partly because there may be few symptoms of hypoglycaemiaLow blood glucose levels., which would usually signal danger,[6] and partly because it may be brought on by morning sickness.[9] Read more about hypoglycaemia.

Worsening of diabetic complications

Diabetic complications such as eye (retina) and kidney problems may worsen with pregnancy. The severity is related to how bad the complications were before pregnancy.[6]

Pregnancy care with diabetes

Pre-conception care

If you have diabetes and are planning to become pregnant, pre-conceptionThe fertilisation of an ovum by a sperm cell: the start of pregnancy. counselling can be helpful. An association has been found between unplanned pregnancies and poor pregnancy outcomes,[10] so it is best to be as prepared as possible.

Optimising your bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. control before conceptionThe fertilisation of an ovum by a sperm cell: the start of pregnancy. is key,[5,6] using lifestyle factors such as diet and exercise, as well as medication. It's a good idea to have your medicines reviewed because many drugs used to treat diabetes or its complications are not recommended in pregnancy; for example, statinsA class of drugs that inhibit cholesterol formation in the liver., some bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. pressure-lowering medications and most oral antidiabetic drugs.[5]

If you have diabetes and you would like to become pregnant, you should also be assessed for complications of diabetes including kidney problems and cardiovascular disease, and have your eyes tested for retinal disease.[1,5] Find out more about the complications of diabetes.

You also need to be treated for any complications of diabetes, including kidney, eye and cardiovascular problems.[5] As pregnancy may lead to worsening of diabetic retinopathy, this should be treated before pregnancy.[1] If you have any kidney problems associated with your diabetes, you will need careful blood pressure management during pregnancy.[1,6]

Any woman planning to become pregnant, whether or not she has diabetes, is usually advised to take the vitamin folic acid for at least 3 months before trying to become pregnant, and for the first three months of pregnancy, as this helps to prevent birth defects.[6]

Care during pregnancy

Close control of bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. is important throughout pregnancy.[6] In some cases, this may be achieved by diet and non-weight-bearing, non-impact exercise. However, insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. may be needed if good control of bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. levels cannot be achieved by lifestyle measures alone. Insulin resistanceThe ability of a microbe, such as a type of bacteria, to resist the effects of antibiotics or other drugs. usually increases over the course of the pregnancy, so the insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. dosage will need adjustment.[1] Find out more about insulin therapy.

Most women who need antidiabetic treatment during pregnancy are given insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. rather than oral antidiabetic medications. This is because many such tablets can cross the placentaThe organ that nourishes the embryo during pregnancy and also eliminates waste. and affect the fetusAn unborn child from eight weeks of development onwards..[6] Recent research suggests, however, that the oral hypoglycaemic drug glibenclamide (also known as glyburide) can safely be given for gestational diabetesAny level of glucose intolerance first detected during pregnancy. in the second and third trimesters of pregnancy as it does not cross the placentaThe organ that nourishes the embryo during pregnancy and also eliminates waste..[3]

Because of the greater risk of hypoglycaemiaLow blood glucose levels. during pregnancy, you may be advised to test your bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. before driving anywhere. Also, it may help if someone close to you has a glucagonA hormone produced by the pancreas that broadly opposes the actions of insulin and so increases the blood sugar (glucose) level. kit to treat severe hypoglycaemiaLow blood glucose levels..[6] Learn more about hypoglycaemia.

In the third trimesterA period of three months often used to describe the stage of pregnancy, where there are three - first, second and third trimesters., regular ultrasound scans are advisable to assess fetal growth. This is very important to determine whether there are any adverse effectsUndesirable side-effects of medication. on the fetusAn unborn child from eight weeks of development onwards. from maternal glucoseA simple sugar that is an important source of energy in the body. levels that are too high or too low.[1,6]

One complicationA condition that is linked to, or is a consequence of, another disease or procedure. of diabetes called ketoacidosisHigh acidity of the blood and tissues combined with high levels of ketones in the blood. Ketones are produced during the breakdown of fat., which may lead to coma, is potentially dangerous for both the pregnant woman and the fetusAn unborn child from eight weeks of development onwards.. Factors that may lead to diabetic ketoacidosisCondition mainly found in type 1 diabetes, in which high levels of ketones are present; these are acidic compounds produced by fat breakdown. in pregnancy include infectionInvasion by organisms that may be harmful, for example bacteria or parasites., vomiting, insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. pump failure and some medicines such as corticosteroidsA group of hormones that are produced by the adrenal glands, which sit on top of the kidneys.. Treatment is given in hospital and includes fluid replacement, an insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. infusion, checking for and correcting any underlying causes and continual fetal monitoring.[11] Read more about diabetic ketoacidosis.

Birth

If you have diabetes, it is important to decide on a birth plan with your healthcare team. Sometimes, early delivery is advised at about 38 weeks' gestationIn pregnancy, the time from conception to birth., although the ideal timing will vary from woman to woman. If early delivery is needed, you may be given high-dose steroids to help the fetal lungs develop. Steroids may worsen insulin resistanceA reduced response of the body to the hormone insulin, resulting in raised blood glucose levels., though, so you may be given more insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. as well.[6]

It is vital that the pregnant woman's bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. glucoseA simple sugar that is an important source of energy in the body. is well-controlled over the few hours before birth to reduce the risk of neonatal hypoglycaemiaLow blood glucose levels.. Usually, a glucoseA simple sugar that is an important source of energy in the body. and insulinA hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. infusion is given.[1,6]

References: 
  1. Bottalico JN. Diabetes in pregnancy. JAOA 2001; 101: S10-13.
  2. Butte NF. Carbohydrate and lipidOne of a group of compounds that are an important energy source. metabolismThe chemical reactions necessary to sustain life. in pregnancy: normal compared with gestational diabetesAny level of glucose intolerance first detected during pregnancy. mellitus. Am J Clin Nutr 2000; 71(suppl): 1256S-61S.
  3. Kelly L, Evans L, Messenger D. Controversies around gestational diabetesAny level of glucose intolerance first detected during pregnancy.: practical information for family doctors. Can Fam Physician 2005; 51: 688-95.
  4. Buchanan TA, Xiang AH. Gestational diabetes mellitusDisordered energy metabolism and high levels of glucose in the blood owing to a lack of insulin, or poor response of the body to insulin.. J Clin Inv 2005; 115: 485-91.
  5. Kitzmiller JL, Block JM, Brown FM et al. Managing pre-existing diabetes for pregnancy. Diabetes Care 2008; 31: 1060-79.http://care.diabetesjournals.org/content/31/5/1060.full.pdf+html?sid=ffc54ca3-77d3-4979-8fb2-c6131692df36
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  8. Dabelea D. The predisposition to obesityExcess accumulation of fat in the body. and diabetes in offspring of diabetic mothers. Diabetes Care 2007; 30: S169-74.
  9. Nielsen LR, Pedersen-Bjergaard U, Thorsteinsson B et al. Hypoglycemia in pregnant women with type 1 diabetes: Predictors and role of metabolic control. Diabetes Care 2008; 31: 9-14.
  10. Griffiths F, Lowe P, Boardman F et al. Becoming pregnant: exploring the perspectives of women living with diabetes. Br J Gen Pract 2008; 58: 184-90.
  11. Kamalakannan D, Baskar V, Barton DM, Abdu TAM. Diabetic ketoacidosisHigh acidity of the blood and tissues combined with high levels of ketones in the blood. Ketones are produced during the breakdown of fat. in pregnancy. Postgrad Med J 2003; 79: 454-7.