Diabetes mellitus and pregnancy

For pregnant women with diabetes mellitus some particular challenges for both mother and child. If the woman has diabetes as an intercurrent disease in pregnancy, it can cause early labor, birth defects, and very large babies.

Planning in advance is emphasized if one wants to have a baby and has type 1 diabetes mellitus or type 2 diabetes mellitus. Pregnancy management for diabetics needs stringent blood glucose control even in advance of having pregnancy.

Physiology

During a normal pregnancy, many physiological changes occur such as increased hormonal secretions that regulate blood glucose levels, such as a glucose-'drain' to the fetus, slowed emptying of the stomach, increased excretion of glucose by the kidneys and resistance of cells to insulin.

Risks for the child

The risks of maternal diabetes to the developing fetus include miscarriage, growth restriction, growth acceleration, fetal obesity (macrosomia), mild neurological deficits,^[1] polyhydramnios and birth defects. A hyperglycemic maternal environment has also been associated with neonates that are at greater risk for development of negative health outcomes such as future obesity, insulin resistance, type 2 diabetes mellitus, and metabolic syndrome.^[2]

Mild neurological and cognitive deficits in offspring — including increased symptoms of ADHD, impaired fine and gross motor skills, and impaired explicit memory performance — have been linked to pregestational type 1 diabetes and gestational diabetes.^[3][4][5] Prenatal iron deficiency has been suggested as a possible mechanism for these problems.^[6]

Birth defects are not currently an identified risk for the child of women with gestational diabetes, since those primarily occur in the latter part of pregnancy, where vital organs already have taken their most essential shape.

Having diabetes type I or II prior to pregnancy has a 2- to 3-fold^[7] increase in risk of birth defects. The cause is, e.g., oxidative stress, by activating protein kinase C^[7] and lead to apoptosis of some cells.^[7]

Importance of blood glucose level during pregnancy

High blood sugar level is harmful to the mother and her fetus. Experts advise diabetics to maintain blood sugar level close to normal range for 2 to 3 months before planning for pregnancy. Managing blood sugar close to normal before and during pregnancy helps to protect the health of mother and the baby.

Insulin may be needed for type 2 diabetics instead of oral diabetes medication. Extra insulin may be needed for type 1 diabetics during pregnancy. Doctors may advise to check blood sugar more often to maintain near-normal blood sugar levels.

Diabetes pregnancy management

Diabetes mellitus may be effectively managed by appropriate meal planning, increased physical activity and properly-instituted insulin treatment. Some tips for controlling diabetes in pregnancy include:

• Meals – Cut down sweets, eats three small meals and one to three snacks a day, maintain proper mealtimes, and include balanced fiber intake in the form of fruits, vegetables and whole-grains.
• Increased physical activity - walking, swimming/aquaerobics, etc.
• Monitor blood sugar level frequently, doctors may ask to check the blood glucose more often than usual.
• The blood sugar level should be below 95 mg/dl (5.3 mmol/l) on awakening, below 140 mg/dl (7.8 mmol/l) one hour after a meal and below 120 mg/dl (6.7 mmol/l) two hours after a meal.
• Each time when checking the blood sugar level, keep a proper record of the results and present to the health care team for evaluation and modification of the treatment. If blood sugar levels are above targets, a perinatal diabetes management team may suggest ways to achieve targets.
• Many may need extra insulin during pregnancy to reach their blood sugar target. Insulin is not harmful for the baby.

Breast feeding

Breast feeding is good for the child even with a mother with diabetes mellitus. Some women wonder whether breast feeding is recommended after they have been diagnosed with diabetes mellitus. Breast feeding is recommended for most babies, including when mothers may be diabetic. In fact, the child’s risk for developing type 2 diabetes mellitus later in life may be lower if the baby was breast-fed. It also helps the child to maintain a healthy body weight during infancy. However, the breastmilk of mothers with diabetes has been demonstrated to have a different composition than that of non-diabetic mothers, containing elevated levels of glucose and insulin and decreased polyunsaturated fatty acids.^[8] Although benefits of breast-feeding for the children of diabetic mothers have been documented, ingestion of diabetic breast milk has also been linked to delayed language development on a dose-dependent basis.^[8]

Classification

The White classification, named after Priscilla White^[9] who pioneered research on the effect of diabetes types on perinatal outcome, is widely used to assess maternal and fetal risk. It distinguishes between gestational diabetes (type A) and diabetes that existed before pregnancy (pregestational diabetes). These two groups are further subdivided according to their associated risks and management.^[10]

There are 2 classes of gestational diabetes (diabetes which began during pregnancy):

• Class A₁: gestational diabetes; diet controlled
• Class A₂: gestational diabetes; medication controlled

The second group of diabetes which existed before pregnancy can be split up into these classes:

• Class B: onset at age 20 or older or with duration of less than 10 years
• Class C: onset at age 10-19 or duration of 10–19 years
• Class D: onset before age 10 or duration greater than 20 years
• Class E: overt diabetes mellitus with calcified pelvic vessels
• Class F: diabetic nephropathy
• Class R: proliferative retinopathy
• Class RF: retinopathy and nephropathy
• Class H: ischemic heart disease
• Class T: prior kidney transplant

An early age of onset or long-standing disease comes with greater risks, hence the first three subtypes.

Treatment of pregnant women with diabetes

Blood glucose levels in pregnant woman should be regulated as strictly as possible. Higher levels of glucose early in pregnancy are associated with teratogenic effects on the developing fetus.^[11] A Cochrane review published in 2016 was designed to find out the most effective blood sugar range to guide treatment for women who develop gestational diabetes mellitus in their pregnancy. The review concluded that quality scientific evidence is not yet available to determine the best blood sugar range for improving health for pregnant women with diabetes and their babies.^[12]

See also

• Diabetes mellitus
• Gestational diabetes
• Pregnancy

Footnotes

External links

• CDC’s National Center on Birth Defects and Developmental Disabilities