Yes, for the standard 1-hour pregnancy screening, fasting is usually not needed; follow your clinic’s specific prep if they give one.
The 1-hour pregnancy glucose screening checks how your body handles a measured sugar drink. Most clinics call it the “glucose challenge” or “screening,” and it’s a first step. You drink a 50-gram glucose beverage, wait one hour, then have a blood draw. No special diet changes are typical for this visit, and fasting isn’t standard unless your provider tells you otherwise.
What This Screening Is And Why It’s Done
This quick check looks for high blood sugar during pregnancy. If the result is above your clinic’s cut-off, you’ll be scheduled for a longer diagnostic test on a different day. That second test uses a higher sugar dose and adds multiple blood draws to confirm or rule out gestational diabetes.
Fasting Rules For The 1-Hour Glucose Screening
For most patients, fasting isn’t part of the 1-hour appointment. Many clinics encourage a normal breakfast or lunch ahead of time and ask you to avoid high-sugar snacks right before you arrive. Plan to sit during the waiting period and keep the timing tight so the blood draw lands at the one-hour mark. If your office gave written instructions, follow those first.
Why The Instructions Can Differ
Medical groups set ranges and options that clinics adapt to their workflows. Some offices prefer a standard approach for every patient. Others tailor prep based on prior results, time of day, or lab scheduling. If anything in this guide conflicts with your written prep sheet, use the sheet you received at check-in or by email.
At-A-Glance: Test Types And Prep
Use this table to compare the fast, the sugar dose, and the timeline for common tests. This helps you plan meals and transportation for each visit.
| Test | Fasting Needed | What Happens |
|---|---|---|
| 1-Hour Screening (50 g) | No, unless your clinic says so | Drink 50 g glucose, wait 60 minutes, single blood draw |
| 3-Hour Diagnostic OGTT (100 g) | Yes, usually 8–12 hours | Fasting blood draw, drink 100 g, blood draws at 1, 2, and 3 hours |
| Non-Pregnancy OGTT (75 g) | Yes, per lab protocol | Fasting blood draw, drink 75 g, timed blood draws after |
How To Prepare For The 1-Hour Visit
What To Eat
Pick a balanced meal with protein, fiber, and fat so you feel steady while you wait. Eggs with whole-grain toast, yogurt with nuts, or chicken with vegetables are simple picks. Skip candy or sugary drinks during the hour before your appointment. Bring water. You’ll likely be asked to avoid food during the waiting hour after you drink the glucose solution.
What To Bring
- A photo ID and insurance card.
- Any prep sheet your clinic provided.
- Water and a small snack for after the blood draw if you feel light-headed.
- A timer or phone alarm set for 60 minutes once you finish the drink.
Timing And Logistics
Plan to be at the lab for about 75–90 minutes. The first few minutes cover check-in and the drink. The waiting period is sixty minutes. The blood draw takes a few minutes, then you can leave. If you get queasy with sweet drinks, ask for it chilled. Many labs offer flavor options.
What The Result Means
Clinics use different cut-offs to decide who returns for the longer test. Many use 130, 135, or 140 mg/dL at the one-hour mark. Some labs flag very high values as diagnostic without the longer test. Your report will state the threshold used by that site.
If Your Screen Is Above The Cut-Off
You’ll be scheduled for the 3-hour diagnostic test. That visit requires an overnight fast, an initial blood draw, the 100-gram drink, and three more blood draws spaced an hour apart. Plan for a half-day and bring a book or music. Eat a snack afterward to settle your stomach and energy.
If Your Screen Is Below The Cut-Off
No extra testing is needed right now. Keep your routine prenatal visits. If new symptoms show up later in pregnancy, your provider may repeat screening or check at delivery per their protocol.
Step-By-Step Walkthrough Of The 1-Hour Visit
- Check in at the lab or office.
- Receive the 50-gram glucose drink. You’ll be asked to finish it within a set window, often five minutes.
- Start your timer when you take the last sip.
- Sit in the waiting area. Avoid food and avoid smoking or vaping during the hour.
- At the 60-minute mark, a phlebotomist draws your blood.
- You’re done. Ask when and how you’ll receive results.
Common Questions About Food, Drinks, And Meds
Can I Drink Coffee Before The Screening?
Black coffee can nudge blood sugar and cause jitters during the wait. A small cup may be fine if your clinic allows it, but water is a safer bet. Skip sweeteners and creamers on the morning of the test.
What If I’m Taking Prenatal Vitamins Or Iron?
Those don’t replace fasting rules when a fast is required. For the 1-hour screen, you can take them as usual unless your clinic says to hold iron due to nausea. For the longer test, ask your provider if you should take pills after the first blood draw.
What If I Feel Nauseated Or Light-Headed?
Let the staff know right away. Sitting with feet up, sipping water after the draw, and a protein snack can help. If you vomit the drink, the test is usually repeated on another day.
When The Longer Test Is Needed
The 3-hour diagnostic visit confirms or rules out gestational diabetes. It uses fasting plus three timed blood draws after a 100-gram drink. You’ll stay at the clinic the whole time. Wear comfy clothes. Bring a wrap or sweater since labs run cool.
Why Fasting Matters For The 3-Hour Test
Fasting sets a baseline so your team can compare sugar levels over time. That baseline, plus the 1-, 2-, and 3-hour values, tells the full story of how your body handles the sugar load. Meeting a set number of abnormal values leads to a diagnosis and a care plan.
Numbers At A Glance: Typical Cut-Offs
The values below are common in many U.S. practices. Your lab may use slightly different targets or flags. Your report will list the exact thresholds used for your test.
| Test Stage | Typical Threshold | What Happens |
|---|---|---|
| 1-Hour Screen (50 g) | 130–140 mg/dL cut-off; very high values may be diagnostic | At or above cut-off → schedule 3-hour test |
| 3-Hour OGTT Fasting | Clinic-specific fasting target (often <95 mg/dL) | Counts toward diagnosis if at or above target |
| 3-Hour OGTT 1/2/3 Hours | Timed values with set limits per lab | Two or more high values → diagnosis |
Tips To Make The Visit Smoother
Scheduling
Pick a time that lines up with your usual meal routine. Morning slots fit many schedules. If your office told you not to fast, eat as you normally do and arrive a bit early to settle in.
Comfort
Wear layers and short sleeves for easy blood draws. Bring a bottle of water. Plan a light snack for after the draw, especially if you’re sensitive to sugar swings.
Results
Ask how you’ll receive the report. Many clinics release it through a portal within a day or two. If your number is above the cut-off, expect a message about the longer test with clear instructions about fasting and timing.
When To Call Your Provider
- You can’t keep the drink down during the wait.
- You took the drink late or missed the 60-minute window.
- You used a sweetened beverage within the waiting hour by mistake.
- You felt faint, needed help, or had unusual symptoms afterward.
Helpful References To Read Mid-Pregnancy
For a clear walkthrough of the screening steps, see the glucose screening tests during pregnancy. For the longer visit where fasting is part of the plan, this glucose tolerance test page explains the full schedule and blood draw timing. Many labs also share prep that states fasting isn’t required for the 1-hour visit; one example is a national lab note that the one-hour specimen is drawn after a 50-gram challenge with no fasting sample needed.
Bottom Line For The 1-Hour Screen
Most patients don’t fast for the short screening. Eat a normal meal, skip sugary snacks right before you arrive, finish the drink on time, and plan for one blood draw at the hour mark. If your number is over the cut-off, the next step is the longer, fasting test on a separate day.