This article provides a review of updates in the management of gestational diabetes mellitus published in Standard of Care by the American Diabetes Association for the year 2023.

Preconception counselling

1. Regular diabetes care should include preconception counselling. Starting at puberty and continuing in all diabetic women and reproductive potential.
2. Family planning should be discussed, and effective contraception should be prescribed and used until a woman's treatment regimen and A1C are optimised for pregnancy which is ideally <6.5%, to reduce the risk of congenital anomalies, preeclampsia, macrosomia, and preterm birth.

Preconception care

1. Women with preexisting diabetes who are planning a pregnancy should ideally be managed beginning in preconception in a multidisciplinary clinic including an endocrinologist, internist, dietitian, nutritionist, and diabetes care and education specialist.
2. In addition to focused attention on achieving glycemic targets, standard preconception care should be augmented with extra focus on medical nutrition therapy, diabetes education, and screening for diabetes co-morbidities and complications.
3. Dilated eye examinations should ideally occur before pregnancy or in the first trimester in patients with preexisting diabetes due to the risk of development of retinopathy during pregnancy, and then patients should be monitored every trimester and for 1 year postpartum as indicated by the degree of retinopathy and as recommended by the eye care provider.

Glycemic targets in pregnancy

1. For achieving optimal glucose levels both in GDM and patients with preexisting diabetes the fasting plasma glucose (FPG) as well as postprandial glucose (PPG) levels should be checked. Some individuals with preexisting diabetes should also check blood glucose pre-prandially.

Recommended Glucose targets are:

• FPG <95 mg/dL and
• Either 1-h PPG<140 mg/dL or 2-h PPG<120 mg/dL

2. Due to increased red blood cell turnover, HbA1C is slightly lower during pregnancy in people with and without diabetes. Ideally, the HbA1C target in pregnancy is <6% if this can be achieved without significant hypoglycemia, but the target may be relaxed to <7% if necessary to prevent hypoglycemia.
3. Continuous glucose monitoring (CGM) can help to achieve the A1C target in diabetes and pregnancy. Real-time continuous glucose monitoring can reduce macrosomia and neonatal hypoglycemia in pregnancy complicated by type 1 diabetes.
4. CGM metrics may be used in addition to but should not be used as a substitute for blood glucose monitoring to achieve optimal pre- and postprandial glycemic targets.
5. Commonly used estimated AIC and glucose management indicator calculations should not be used in pregnancy as estimates of A1C.
6. Nutrition counselling should endorse a balance of macronutrients including nutrient-dense fruits, vegetables, legumes, whole grains, and healthy fats with n-3 fatty acids that include nuts and seeds and fish in the eating pattern.

Management of gestational diabetes mellitus (GDM)

1. Lifestyle behaviour change is an essential component of the management of GDM and may suffice as treatment for many individuals. Insulin should be added if needed to achieve glycemic targets.
2. After diagnosis, treatment starts with medical nutrition therapy, physical activity, and weight management, depending on pre-gestational weight. The recommended dietary reference intake for all pregnant people is a minimum of 175 g of carbohydrates, a minimum of 71 g of protein, and 28 g of fibre.
3. Insulin is the choice of medication for treating hyperglycemia in gestational diabetes mellitus. Metformin and Glyburide should not be used as first-line agents, as both cross the placenta to the fetus. Other oral and noninsulin injectable glucose-lowering medications should not be used due to a lack of long-term safety data. Pregnancy-associated with hypertension or preeclampsia or those with a risk of IUGR should not be prescribed metformin due to the potential for growth restriction or acidosis in the setting of placental insufficiency.
4. Metformin when used to treat polycystic ovary syndrome and induce ovulation, should be discontinued by the end of the first trimester.
5. Telehealth visits for pregnant people with GDM improve outcomes compared with standard in-person care.

Management of preexisting type 1 diabetes and type 2 diabetes in pregnancy - insulin use

1. Insulin remains the preferred agent for the management of type 1 and type 2 diabetes in pregnancy.
2. Either multiple daily injections or the use of insulin pumps can be used in pregnancy complicated by type 1 diabetes.

Preeclampsia and aspirin

Pregnant individuals with type 1 or type 2 diabetes should be prescribed low-dose aspirin 100-150 mg/day starting at 12 to 16 weeks of gestation to lower the risk of preeclampsia.

Pregnancy and drug considerations

1. In pregnant individuals with diabetes and chronic hypertension, a blood pressure threshold of 140/90 mmHg for initiation or titration of therapy is associated with better pregnancy outcomes than reserving treatment for severe HTN, with no increase in the risk of small for gestational age birth weight.
2. A blood pressure target of 110-135/85 mmHg is suggested in the interest of reducing the risk for accelerated maternal hypertension.
3. Potentially harmful antihypertensive drugs like ACE inhibitors/Angiotensin receptor blockers which can cause fetal renal dysplasia, oligohydramnios, pulmonary hypoplasia, and IUGR, statins should be stopped before conception and avoided in sexually active individuals of childbearing potential who are not using reliable contraception.
4. Antihypertensive Drugs known to be effective and safe in pregnancy include methyldopa, nifedipine, labetalol, diltiazem, clonidine, and prazosin.

Postpartum care

1. Insulin resistance decreases dramatically immediately postpartum, and insulin requirements need to be evaluated and adjusted as they are often roughly half the pre-pregnancy requirements for the initial few days postpartum.
2. A contraceptive plan should be discussed and implemented with all people with diabetes of reproductive potential.
3. Screen individuals with a recent history of gestational diabetes mellitus at 4-12 weeks postpartum, using the 75-g OGTT and clinically appropriate non-pregnancy diagnostic criteria. A person's lifetime absolute chance of getting diabetes following GDM rises linearly, being approximately 20% at 10 years, 30% at 20 years, 40% at 30 years, 50% at 40 years and 60% at 50 years.
4. Individuals with overweight/obesity and a history of GDM found to have pre-diabetes should receive intensive lifestyle interventions and/or metformin to prevent diabetes.
5. Breastfeeding is recommended to reduce the risk of maternal type 2 diabetes and should be considered when choosing whether to breastfeed or formula feed.
6. Individuals with a history of GDM should have lifelong screening for the development of type 2 diabetes or pre-diabetes every 1-3 years.
7. Postpartum care should include psychosocial assessment and support for self-care.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Hitesh Saraogi is a diabetologist, physician and an obesity specialist at Dhanvantari Hospital, Raj Nagar Extension, Ghaziabad.