Fact Explanation
Presenting with a history of pre-existing diabetes Chronic diabetes in pregnancy is increasing in incidence due to a higher incidence of pregnancies in advanced maternal age. Both type 1 and 2 diabetes mellitus may complicate pregnancy. The majority of patients diagnosed with glucose tolerance are gestational diabetics while type 1 diabetes accounts for 7.5% and type 2 diabetes accounts for 5% of patients.[1] Pregnancy itself is a diabetogenic state.The pregnancy worsens the diabetic state. The maternal carbohydrate metabolism is modified to increase fetal supply of glucose. Hormones produced during pregnancy – estrogen, progesterone, prolactin, Human placental lactogen (hPL) have anti-insulin properties. The insulin action is resisted. Body lipids and proteins are mobilized. Free fatty acids and amino-acids are used for maternal energy needs while maintaining an adequate supply of glucose to the fetus. Gather information regarding the duration, control, current treatment and complications of diabetes mellitus.
Polyuria, polydipsia and nocturia These features can be present in women with poor control of diabetes. These symptoms and diabetic complications are more prominent in type 1 diabetes patients.
Difficulty in controlling blood glucose / Ketosis Pre-pregnancy pancreatic insufficiency is worsened during pregnancy. Control of blood glucose is difficult and often requires higher doses of insulin.
Diagnosis during screening Blood glucose screening during the antenatal period identifies a majority of patients. Suspect pregestational diabetes in patients who are diagnosed early in their pregnancies.
Identified during physical examination of the mother Pregnant women with pregestational diabetes have an increased risk of macrosomia and polyhydramnios. Increased symphysio-fundal height and increased estimated fetal weight may be detected during abdominal examination.
Presentation with maternal complications Pre-eclampsia is frequently associated with diabetic women. In addition to chronic diabetes the patient may be hypertensive. The patient may present with non-specific symptoms such as headache, vomiting, visual disturbances and frothy urine. These patients have a significant risk of eclampsia and other complications – acute renal failure, DIC.[2] Infections are common due to impaired immunity. Vaginal Candidiasis presents with a thick curd like discharge with vulval symptoms such as soreness, pruritus etc. Urinary tract infections are common infections in diabetic patients. It may be complicated by acute pyelonephritis. Pre-existing vasculopathy (retinopathy, nephropathy and neuropathy) usually does not worsen during pregnancy. Postpartum thyroiditis is a known complication in type 1 diabetic women.[3]
Assess other cardiovascular risk factors Look for evidence of hypertension, hyperlipidaemia and cardiovascular disease.
  1. Diabetes in pregnancy. National institute of health and clinical excellence, 2008 [Viewed on 2014 August 16]. Available from : http://www.nice.org.uk/guidance/cg63/resources/guidance-diabetes-in-pregnancy-pdf
  2. EL MALLAH KO, NARCHI H, KULAYLAT NA, SHABAN MS. Gestational and pre-gestational diabetes: comparison of maternal and fetal characteristics and outcome. Int J Gynaecol Obstet [online] 1997 Aug, 58(2):203-9 [viewed 19 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/9252256
  3. TAGNARO-GREEN A. Approach to the patient with postpartum thyroiditis. J Clin Endocrinol Metab [online] 2012 Feb, 97(2):334-42 [viewed 19 August 2014] Available from: doi:10.1210/jc.2011-2576


Fact Explanation
Physical examination of the mother Usually normal.
Obstetric abdominal examination : Increased estimated fetal weight Maternal hyperglycaemia leads to increased glucose supply to the fetus. Increased glucose, amino-acid supply to the fetus stimulates growth. In addition the resulting fetal hyperinsulinaemia further promotes fetal growth due to the growth factor like action of insulin. Pre-existing vasculopathy may even cause intra-uterine growth restriction.[1]
Obstetric abdominal examination : Features of polyhydramnios Polyhydramnios is a complication of diabetic pregnancies. The fetal hyperglycaemia promotes osmotic dieresis and increased urine production by the fetal kidneys. This results in excess amniotic fluid. The abdomen appears tense. The symphysio-fundal height is increased and the fetal parts are difficult to palpate.
  1. VAMBERGUE A, FAJARDY I. Consequences of gestational and pregestational diabetes on placental function and birth weight World J Diabetes [online] 2011 Nov 15, 2(11):196-203 [viewed 19 August 2014] Available from: doi:10.4239/wjd.v2.i11.196

Differential Diagnoses

Fact Explanation
Gestational diabetes Gestational diabetes (GDM) is defined as carbohydrate intolerance of varying severity with the onset or first recognition during the current pregnancy. It affects up to affects ∼14% of pregnancies in a year in the United States.[1] Inability of the pancreas to respond to the increased insulin resistance due to production of anti-insulin hormones during pregnancy predisposes to gestational diabetes. The majority of women are asymptomatic and are identified during screening. Compared to pre-gestational diabetes the severity of blood glucose elevation is less and control is relatively easy.[2] Maternal complications are mainly from infection and due to pre-eclapmsia. Ketosis or features of vasculopathy are rare. The maternal hyperglycaemia – fetal hyperinsulinaemia model explains the complications associated with gestational diabetes. The fetus is often macrosomic and there is an increased risk of shoulder dystocia and operative delivery. During the neonatal period neonatal hypoglycaemia, respiratory distress syndrome, electrolyte changes and hyperbilirubinaemia are common complications. Patients with gestational diabetes can usually be managed with dietary control alone and only about 15% require insulin therapy. Patients with gestational diabetes have an increased risk of recurrence in subsequent pregnancies and an increased risk of type 2 diabetes in the future.
  1. KIM C., NEWTON K. M., KNOPP R. H.. Gestational Diabetes and the Incidence of Type 2 Diabetes: A systematic review. Diabetes Care [online] 2002 October, 25(10):1862-1868 [viewed 19 August 2014] Available from: doi:10.2337/diacare.25.10.1862
  2. EL MALLAH KO, NARCHI H, KULAYLAT NA, SHABAN MS. Gestational and pre-gestational diabetes: comparison of maternal and fetal characteristics and outcome. Int J Gynaecol Obstet [online] 1997 Aug, 58(2):203-9 [viewed 19 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/9252256

Investigations - for Diagnosis

Fact Explanation
Known diabetic pregnant women Patients are usually diagnosed with diabetes prior to pregnancy. Additional diagnostic investigations are not required.
Oral glucose tolerance test (OGTT) OGTT can be used to confirm the diagnosis. Both the 75g two hour OGTT and the 100g three hour OGTT are used to confirm the diagnosis. The patient is advised to consume an unrestricted diet including > 150g of carbohydrate per day for 3 days prior to the test. The test is started after an overnight fast of at least 8 hours where the patient is given the amount of glucose to consume over about 20 mins. The patient should refrain from smoking during the test. Blood glucose measurements are taken at the beginning, at 1h,2h and 3h periods. The cut off values used vary from country to country. Commonly used cut off values : fasting < 95 mg/dl, 1-hour > 180 mg/dl, 2-hour > 155 mg/dl and 3-hour > 140 mg/dl. Two or more abnormal values are required for diagnosis. The cutoff points used by the Hyperglycaemia and adverse pregnancy outcome study are – Fasting blood glucose > 92 mg/dl, 1-hour > 180 mg/dl and 2-hour > 153 mg/dl.[1]
Random blood glucose assessment High risk patients with clear symptoms of hyperglycaemia can be diagnosed by a random blood glucose assessment. The cutoff value used is > 200 mg/dl.
  1. HAPO STUDY COOPERATIVE RESEARCH GROUP. The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study. Int J Gynaecol Obstet [online] 2002 Jul, 78(1):69-77 [viewed 19 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12113977

Investigations - Followup

Fact Explanation
Blood glucose measurements Chronic diabetes women require frequent blood glucose level monitoring. Target blood sugar levels : fasting blood sugar < 108mg/dl and post-prandial blood sugar < 126mg/dl. Blood sugar series assesses the blood glucose levels before and after the main meals – breakfast, lunch and dinner. In certain instances hospital admission may be required to adjust the treatment regime and achieve blood glucose control. Home glucose monitoring improves patient participation and hence promotes better control.
HbA1c HbA1c can be used assess the blood glucose control over the last 2-3 month period. A high HbA1c level at the end of the first trimester indicates poor glucose control during the peri-conceptional period. These patients have a higher risk of fetal anomalies.
Urine for microscopy and culture To exclude asymptomatic bacteriuria and overt urinary tract infection.
Ultrasound scan First trimester fetal ultrasound scan for accurate estimation of the gestational age is important since majority of pregnancies are induced at 38 weeks. Early growth lag identified by this scan may indicate an increased risk of fetal anomalies and abortion. Fetal anomaly scan is done at 22-24 weeks. Cardiac, neural tube and renal anomalies are common in pre-getational diabetic women. Caudal regression syndrome although rare is a characteristic anomaly associated with pre-gestational diabetes. During the third trimester ultrasound scan is important to monitor for fetal macrosomia and other complications. The fetus may follow varies growth patterns. Peri-conceptional hyperglycaemia is associated with an accelerated growth which continues up to the late third trimester.[1]
Fetal echocardiography Fetal echocardiography performed during 20-24 weeks can identify cardiac anomalies. It has being shown that cardiac function abnormalities occur prior to the appearance of structural abnormalities.[2]
Doppler study of placental blood flow Assess uterine artery blood flow if vasculopathy is suspected. The fetus may show growth restriction if blood supply is limited.[3]
  1. WONG SF, CHAN FY, OATS JJ, MCINTYRE DH. Fetal growth spurt and pregestational diabetic pregnancy. Diabetes Care [online] 2002 Oct, 25(10):1681-4 [viewed 19 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/12351461
  2. RUSSELL NE, FOLEY M, KINSLEY BT, FIRTH RG, COFFEY M, MCAULIFFE FM. Effect of pregestational diabetes mellitus on fetal cardiac function and structure. Am J Obstet Gynecol [online] 2008 Sep, 199(3):312.e1-7 [viewed 19 August 2014] Available from: doi:10.1016/j.ajog.2008.07.016
  3. PIETRYGA M, BRAZERT J, WENDER-OZEGOWSKA E, BICZYSKO R, DUBIEL M, GUDMUNDSSON S. Abnormal uterine Doppler is related to vasculopathy in pregestational diabetes mellitus. Circulation [online] 2005 Oct 18, 112(16):2496-500 [viewed 19 August 2014] Available from: doi:10.1161/CIRCULATIONAHA.104.492843

Management - General Measures

Fact Explanation
Patient education The patient should be provided information regarding the natural history of the disease, aetiology, investigations and treatment options. Counsel the patient regarding the complications to the mother and the fetus. It is important to motivate the patient to get involved in the management process.
Multi-disciplinary management Ideally these women should be managed in specific diabetic clinics. Physician, dietician, neonatologist should be involved in the management in addition to the obstetrician and midwife staff.
Dietary therapy All diabetic pregnant women require diet control. Patients with gestational diabetes are initially started on dietary therapy. Review blood sugar control after two to three weeks. If adequate control is maintained dietary therapy alone may be adequate. Patients should be encouraged to have a calory intake of 24-30kcal/kg body weight. Food items with a low glycaemic index are more suitable. The diet should contain adequate protein and fiber. Avoid sweet products and high fat food items. The calory intake should be divided among 3 main meals and 3 snacks. A night snack can prevent nocturnal hypoglycaemia. Dietary control also known as Medical nutritional therapy is the cornerstone in management of these patients and has being shown to reduce adverse pregnancy outcomes.[1]
Adequate exercise Encourage suitable aerobic exercises. Upper body exercises are safe and effective. The current recommendation is regular moderate intensity exercise for 30 minutes duration(most days of the weeks).[2]
Frequent clinic visits These patients require more frequent antenatal monitoring. Blood glucose level, blood pressure, weight gain, proteinuria and fetal growth should be monitored at these visits. Monitor progression of diabetic retinopathy and diabetic nephropathy.[3] Hospitalization for adjustment of treatment may be required if blood glucose control is poor.
Continuation of good glycaemic control They should be encouraged to continue the dietary changes and exercise adopted during the pregnancy. Counseling should be provided on the risk of diabetes related complications in subsequent pregnancies.
Encourage pre-pregnancy planning for future pregnancies Pre-pregnancy counseling and adjustments to the treatment methods may improve maternal and fetal outcome. It advisable to encourage these patients to complete their families at a young age.[4] [5]
  1. JOVANOVIC L. Medical nutritional therapy in pregnant women with pregestational diabetes mellitus. J Matern Fetal Med [online] 2000 Jan-Feb, 9(1):21-8 [viewed 19 August 2014] Available from: doi:10.1002/(SICI)1520-6661(200001/02)9:1<21::AID-MFM6>3.0.CO;2-P
  2. COLBERG SR, CASTORINO K, JOVANOVIč L. Prescribing physical activity to prevent and manage gestational diabetes World J Diabetes [online] 2013 Dec 15, 4(6):256-262 [viewed 19 August 2014] Available from: doi:10.4239/wjd.v4.i6.256
  3. MATHIESEN ER, RINGHOLM L, DAMM P. Pregnancy management of women with pregestational diabetes. Endocrinol Metab Clin North Am [online] 2011 Dec, 40(4):727-38 [viewed 19 August 2014] Available from: doi:10.1016/j.ecl.2011.08.005
  4. WAHABI HA, ALZEIDAN RA, ESMAEIL SA. Pre-pregnancy care for women with pre-gestational diabetes mellitus: a systematic review and meta-analysis. BMC Public Health [online] 2012 Sep 17:792 [viewed 19 August 2014] Available from: doi:10.1186/1471-2458-12-792
  5. WILLHOITE MB, BENNERT HW JR, PALOMAKI GE, ZAREMBA MM, HERMAN WH, WILLIAMS JR, SPEAR NH. The impact of preconception counseling on pregnancy outcomes. The experience of the Maine Diabetes in Pregnancy Program. Diabetes Care [online] 1993 Feb, 16(2):450-5 [viewed 19 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/8432216

Management - Specific Treatments

Fact Explanation
Insulin therapy Insulin therapy is required is often requires in addition to dietary therapy.[1] Increase the insulin dosage as required. A mixture of short acting and medium acting insulin is preferred. The total dose is divided into 2/3 in the morning and 1/3 in the evening. Insulin is administered 20-30 minutes prior to the meal. The regimes used differ depending on the preference of the clinician.
Oral hypoglycaemic drugs Generally avoided due to the risk of fetal hypoglycaemia after passing through the placenta. Newer evidence suggests the possibility of using metformin during pregnancy. The efficacy and safety of metformin during the antenatal period is associated with a reduction in immediate pregnancy outcome.[2] The evidence on the long term effects on the fetus is still limited. Preferably the patient should be converted to insulin prior to conception.
Time of delivery Patients with pregestational diabetes are usually induced at 38 weeks gestation. This is due to the risk of sudden intrauterine death. Both mechanical and medical methods of induction of labor can be used.
Mode of delivery Diabetes alone is not an indication for caesarian section. Caesarian section is requires more often due to macrosomia and other complications.
Management during labor Labor needs close supervision. It is important to maintain euglycaemia during labor. The morning insulin dose is skipped and an insulin+dextrose infusion is started. Blood glucose levels are monitored frequently and adjustments are made according to a sliding scale. Provide adequate pain relief to the mother by epidural anesthesia. Maintain the partogram. Monitor fetal heart rate continuously. An experienced obstetrician and pediatrician should be present at the time of delivery if fetal complications of macrosomia such as shoulder dystocia, obstructed labor, birth asphyxia, birth injuries are expected.[3]
Neonatal care Neonates require intensive monitoring during the early postpartum period. Common complications during this period are hypoglycaemia, hypothermia, metabolic changes, respiratory distress syndrome and hyperbilirubinaemia. Neonatal hypoglycaemia is an important complication. The blood glucose level should be monitored frequently. Encourage early breast feeding.[4]
Postpartum care The insulin requirement is reduced after delivery. The women may be started on her pre-pregnancy treatment. Monitor the blood glucose levels within the first 48h.
Contraception Barrier methods, low dose pills and depot preparations of progesterone are preferred. High estrogens pills are avoided due to the effect on glucose metabolism. Intra-uterine devices are also avoided due to the risk of infection.[5]
  1. KITZMILLER J. L., BLOCK J. M., BROWN F. M., CATALANO P. M., CONWAY D. L., COUSTAN D. R., GUNDERSON E. P., HERMAN W. H., HOFFMAN L. D., INTURRISI M., JOVANOVIC L. B., KJOS S. I., KNOPP R. H., MONTORO M. N., OGATA E. S., PARAMSOTHY P., READER D. M., ROSENN B. M., THOMAS A. M., KIRKMAN M. S.. Managing Preexisting Diabetes for Pregnancy: Summary of evidence and consensus recommendations for care. Diabetes Care [online] 2008 February, 31(5):1060-1079 [viewed 19 August 2014] Available from: doi:10.2337/dc08-9020
  2. FEIG D. S., MOSES R. G.. Metformin Therapy During Pregnancy: Good for the goose and good for the gosling too?. Diabetes Care [online] December, 34(10):2329-2330 [viewed 19 August 2014] Available from: doi:10.2337/dc11-1153
  3. Diabetes in pregnancy. National institute of health and clinical excellence, 2008 [Viewed on 2014 August 16]. Available from : http://www.nice.org.uk/guidance/cg63/resources/guidance-diabetes-in-pregnancy-pdf
  4. RAY JG, VERMEULEN MJ, SHAPIRO JL, KENSHOLE AB. Maternal and neonatal outcomes in pregestational and gestational diabetes mellitus, and the influence of maternal obesity and weight gain: the DEPOSIT study. Diabetes Endocrine Pregnancy Outcome Study in Toronto. QJM [online] 2001 Jul, 94(7):347-56 [viewed 19 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/11435630
  5. MøLSTED-PEDERSEN L, SKOUBY SO, DAMM P. Preconception counseling and contraception after gestational diabetes. Diabetes [online] 1991 Dec:147-50 [viewed 19 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/1748246