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What Pregnant Women Need To Know About Gestational Diabetes

Updated May 8, 2023

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In 1964, Dr. John B. O’Sullivan, at the NIH, developed a screening test for what is now known as gestational diabetes. The test was developed once it was determined that abnormal carbohydrate metabolism occurred during pregnancy.

This alteration in carbohydrate metabolism was also found to be associated with higher birth weights and perinatal complications.


What about individuals with diabetes or risk factors for diabetes?

Before any further discussion about … What is gestational diabetes? …. it is important to address those with a diagnosis of diabetes or those who have risk factors for preexisting diabetes.

For individuals with diabetes, it is important to control blood sugar prior to conception. Poorly controlled blood sugar at the time of conception is associated with a significant increase in the development of fetal deformities.

If one has risk factors for diabetes at their first prenatal visit, it is important to check a hemoglobin A1C to screen for diabetes early in pregnancy.

* If there is a concern about high blood sugar, the hemoglobin A1C blood test must be drawn at your first prenatal visit. This blood test indicates what your blood sugar level was over the prior three months. This information is extremely valuable, as it will allow your provider to know how well controlled your blood sugar was during early fetal development.

You WANT to know what your HgBA1C is, to both, diagnose gestational diabetes and manage it appropriately during pregnancy.

What can a HgBA1C do for you?

  • Diagnose diabetes
  • Estimate your blood sugar range at the time of conception
  • Predict the risk of fetal deformities

Blood tests used to diagnose Gestational Diabetes: 1-hour screen and 3-hour glucose tolerance test

Value for 1 Hour Glucose Screen: ( 50 GM Glucose)

  • The cut-off point is set at 140

Values for positive 3-hour Glucose Tolerance Test: (100 GM Glucose) **

  • Fasting blood sugar level ≥95
  • 1 hr blood glucose level ≥180
  • 2 hr blood glucose level ≥155
  • 3 hr blood glucose level ≥140

 The 3-hour test confirms gestational diabetes and is positive if two or more of the above numbers are abnormal.

I have explained What is gestational diabetes?…..and how it is diagnosed because there are individuals who are skeptical of the diagnosis. I want to emphasize that there are other medical conditions that are found using screening techniques. (Perhaps the most widespread example is a cardiac stress test for heart disease.)

What are the maternal risk factors and causes of gestational diabetes?

  • Pregnant woman over age 25
  • Family history of diabetes
  • Overweight woman with a BMI of 30 or higher *
  • Woman with the polycystic ovarian syndrome
  • HPL (Human Placental Lactogen)

HPL is produced by the placenta and affects maternal sensitivity to insulin. It affects the body’s ability to use blood sugar. This discovery was a major advancement in the understanding of …  what is now known as gestational diabetes.

* Calculate your Body’s Mass Index (BMI): CLICK HERE (Courtesy of calculator. net)

[wps_icon icon=”check” background=”#31b522″ color=”#ffffff” size=”22″ padding=”6″ radius=”0″]Maternal management of Gestational Diabetes: 

  • Blood sugar monitoring
  • Three small meals and snacks
  • Calculate calories by nutritionist
  • Exercise program

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The following medical supplies are needed to monitor and manage your blood sugar: 

  • Blood sugar monitor
  • Blood sugar test strips
  • Lancets
  • Urine test strips for ketones
  • Journal to log results

* If insulin is required, other supplies will be needed (syringes, etc.)

Training by medical staff:

  • Calibrating and use of blood sugar monitor
  • Urine testing
  • Injecting insulin (if needed)
  • Logging blood sugar values to adjust management

[wps_alert type=”note”][wps_icon icon=”check” background=”#31b522″ color=”#ffffff” size=”18″ padding=”6″ radius=”0″]Fortunately, gestational diabetes most often resolves immediately after delivery of the placenta. This is largely due to the cessation of the production of human placental lactogen (see above). However, individuals with gestational diabetes are at risk to develop adult-onset diabetes later in life.[/wps_alert]

Diabetes test. Pregnant women checking sugar level with glucometer.Gestational diabetes.

Fetal management when the mother has Gestational Diabetes:

Since diabetes during pregnancy is associated with increased birth weights, delayed lung maturation, toxemia, etc.. there are a number of prenatal tests that are routinely performed to ensure fetal well-being, especially as your pregnancy approaches term. (fetal monitoring, ultrasound, etc.)

*I hope this information is helpful. It is not intended to diagnose, treat, cure or prevent any condition; however, the more one understands… What is gestational diabetes? …the more proactive one can be about the management.

How does gestational diabetes affect the baby?

Elevated blood sugar during pregnancy can result in increased birth weight. Elevated blood sugar can make the infant at risk for low blood sugar at birth. When this occurs the baby’s blood sugar is monitored. Other fetal complications can include a greater risk of jaundice and respiratory distress syndrome. Most problems with mother and baby will return to normal after delivery.

[wps_alert type=”note”][wps_icon icon=”check” background=”#31b522″ color=”#ffffff” size=”18″ padding=”6″ radius=”0″]Fetal lung maturity is delayed in diabetic pregnancies.[/wps_alert]

Which could be an issue in the case where a mother has both gestational diabetes and preterm labor.

How does gestational diabetes affect the mother?

  • Due to the larger size of babies born to diabetic mothers, there is an increased risk of cesarean delivery.
  • Gestational diabetes may also increase the risk of the mother developing preeclampsia (elevated blood pressure).

Diet for gestational diabetes?

Gestational Diabetes Diet

Photo Credit: Maternity Comfort Solutions

  • A nutritionist can help design an appropriate diet if you have gestational diabetes.
  • A diet of three small meals with snacks is what can help maintain stable blood sugar.
  • The carbohydrates should be complex and not simple sugars.

* By learning what is gestational diabetes you will better understand why it is so important to make lifestyle changes before and after pregnancy!


  • Doug Penta MD OB/GYN

    Dr. Doug Penta, MD - Co-Founder of Maternity Comfort Solutions Dr. Doug Penta, is a seasoned Obstetrician and Gynecologist with over 38 years of practice, co-founded Maternity Comfort Solutions to provide evidence-based pregnancy and parenting information. A Boston University alum and former Clinical Professor at Harvard, his articles on Maternity Comfort Solutions offer expectant mothers invaluable nutritional insights.

  • Sue Winters RN

    Sue Winters, RN - Co-Founder of Maternity Comfort Solutions Sue combines 20 years of nursing with a rich background in early childhood education. Co-founder of Maternity Comfort Solutions, her articles provide creative toddler activities and practical tips on pregnancy nutrition and baby shower planning, embodying her commitment to supporting families through early parenthood.

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