PERINATOLOGY.comInformation for you about your pregnancy
Patient Handout

Diabetes Before Pregnancy

Type 1 or type 2 diabetes that was present before pregnancy

You had type 1 or type 2 diabetes before pregnancy.

Your insulin needs can change while you are pregnant.

Keeping your sugar near goal helps protect you and your baby.

High sugar early can raise the risk of birth defects. Later, it can raise the risk of a large baby, birth injury, and stillbirth.

Blood sugar goals

Fasting / before meals70-95
1 hour after eating110-140
2 hours after eating100-120
A1C, if safeunder 6%
Unitsmg/dL

What problems can happen?

  • Birth defects: high sugar early can affect the heart, brain, or spine.
  • Large baby: extra sugar can make the baby grow too much.
  • Birth injury: a large baby can be harder to deliver safely.
  • Stillbirth: This means the baby dies before birth. The risk is higher when blood sugar stays too high.
  • After birth: the baby may have low sugar or trouble breathing.

How often should I check sugar?

You may check sugar when you wake up, before meals, and after meals.

If you have type 1 diabetes, ADA recommends a sugar sensor called a CGM.

A common CGM goal is 63-140 mg/dL for more than 70% of the day.

Your team may change your goals to help prevent low sugar.

Extra checks for you

  • A1C and sugar review
  • kidney and urine tests
  • eye exam
  • blood pressure checks
  • medicine and insulin review

Your doctor may ask you to take low-dose aspirin to lower the risk of a serious blood pressure problem called preeclampsia. Do not start it on your own.

Extra checks for the baby

  • 18-22 weeks: a detailed ultrasound
  • 18-22 weeks: a close look at the baby's heart (fetal echo)
  • Later: scans to check growth, often about every 4 weeks
  • About 32 weeks: NST or BPP tests, often twice a week

These tests may start sooner if your sugar is hard to control.

When will I deliver?

If your sugar is well controlled and all is going well, birth is often planned near 39 weeks.

Birth may be earlier if sugar is hard to control or other problems come up.

If the baby is very large, your doctor will talk with you about the safest way to deliver.

What can I do?

  • Take insulin and other medicine as directed.
  • Share your sugar log or CGM.
  • Eat meals and snacks on your plan.
  • Keep all doctor visits.
  • Know how to treat low blood sugar.

Common timing of extra care

Early pregnancyDating scan, A1C, kidney and urine tests, eye exam
12-16 weeksAsk if low-dose aspirin is right for you
18-22 weeksDetailed scan and baby heart scan
About 28 weeks+Growth scans may repeat every 4 weeks
About 32 weeks+NST/BPP often twice a week; plan birth near 39 weeks if all is well
Call your care team right away for vomiting, ketones, repeated low sugar, sugar that stays high, a bad headache, vision changes, or much less baby movement.
Your plan may be different. Your care team will set goals that are safe for you and your baby.
Medical references
  1. American Diabetes Association Professional Practice Committee. Standards of Care in Diabetes - 2026, Section 15: Management of Diabetes in Pregnancy.
  2. American Diabetes Association. Diabetes and Pregnancy.
  3. American College of Obstetricians and Gynecologists. Practice Bulletin No. 201: Pregestational Diabetes Mellitus. Reaffirmed 2025.
  4. American College of Obstetricians and Gynecologists. Pregnancy With Type 1 or Type 2 Diabetes.
  5. American College of Obstetricians and Gynecologists. Indications for Outpatient Antenatal Fetal Surveillance.
  6. American College of Obstetricians and Gynecologists. Low-Dose Aspirin Use During Pregnancy.
  7. American Society of Echocardiography. Guidelines and Recommendations for Performance of the Fetal Echocardiogram. 2023.