When and why are surrogates screened for gestational diabetes?
Every surrogate is screened for gestational diabetes between 24 and 28 weeks of pregnancy, following ACOG guidance. That is the end of the second trimester, and the results are reviewed as she enters the third.
Gestational diabetes is high blood sugar that first appears in pregnancy. As the placenta grows, it makes hormones that make the body resist insulin. Most women make enough extra insulin to keep up. Some do not, and their blood sugar rises. The timing of the screen matches the point when this effect becomes strong enough to show.
It is common, and it is not a sign that the surrogate did anything wrong. The cause is the placenta's hormones.
Screening matters because gestational diabetes usually has no symptoms. Left uncontrolled, it raises the risk of a large baby, a harder delivery and low blood sugar in the newborn. Found and managed, most outcomes are good.
Some women are screened earlier as well, for example after gestational diabetes in a past pregnancy. The OB decides. Dr. Mark Silverberg's review of a candidate's prior prenatal records, before matching, notes any earlier gestational diabetes so the clinic and OB know the history from the start.
How does the glucose challenge test work?
The first step is a screening test called the glucose challenge test, or one-hour test.
- The surrogate drinks a sweet liquid containing 50 grams of glucose. She usually does not need to fast first, though some offices ask her to avoid sugary foods that morning.
- She waits one hour, usually at the lab, without eating.
- A blood sample measures her blood sugar.
The result is compared with the practice's cutoff. Common cutoffs are 130 to 140 mg/dL; a result at or above the cutoff counts as a positive screen.
A positive screen is not a diagnosis. Many women who screen positive do not have gestational diabetes. It means one more test.
Some practices use a different approach: a single two-hour test with a 75-gram drink, done fasting. The OB chooses the method.
What happens if the screen is positive?
The next step is a three-hour glucose tolerance test, which is the diagnostic test.
- She fasts overnight.
- A fasting blood sample is drawn.
- She drinks 100 grams of glucose.
- Blood is drawn again at one, two and three hours.
Gestational diabetes is usually diagnosed when two or more of the four values are above the cutoffs the practice uses.
If she is diagnosed, management usually follows a clear path:
- Diet changes come first, and for many women they are enough.
- Blood sugar checks at home, with a finger-stick meter, several times a day.
- Medication, most often insulin, if diet alone does not keep numbers in range.
- Extra monitoring of the baby, such as growth ultrasounds and, later, nonstress tests.
Gestational diabetes is a pregnancy complication. It is not a breach of the surrogacy agreement, and the agreement covers her care. It usually resolves after delivery.
Why is anemia common in the third trimester, and how is it treated?
During pregnancy, a woman's blood volume rises sharply. The fluid part of the blood increases faster than the red blood cells, so the blood is more diluted. At the same time, the baby and placenta draw on her iron stores to make their own blood supply. By the third trimester, many women are running low.
Anemia is checked with a complete blood count, a routine blood test that measures hemoglobin, the iron-carrying protein in red blood cells. In the third trimester, a hemoglobin under 11 g/dL is generally considered anemic. The OB may also order a ferritin test, which measures stored iron.
Symptoms such as tiredness, shortness of breath and dizziness overlap with ordinary late pregnancy, which is why the blood test matters.
Treatment usually starts with food and supplements:
- Iron-rich foods: lean red meat, poultry, beans, lentils, fortified cereals and leafy greens.
- Vitamin C with iron, such as citrus or tomatoes, which helps absorption.
- An iron supplement when hemoglobin stays low, taken as the OB directs, often apart from calcium, tea and coffee, which reduce absorption.
If oral iron is not enough or is not tolerated, the OB may consider other treatment.
What does Julie's third-trimester nutrition consult cover?
Every Private Label Surrogacy surrogate has at least six nutrition consults with Julie Bendix, MPH, RD, LD, CLC, a registered dietitian and certified lactation counselor. The fifth consult falls in the third trimester and is the most lab-focused. You can see the full schedule on the nutrition program page.
At this consult, Julie reviews:
- The gestational diabetes screen. If the result is normal, she reinforces habits that keep blood sugar steady. If gestational diabetes is diagnosed, she builds a meal plan with the surrogate: carbohydrates spread across meals and snacks, paired with protein and fiber, fewer sugary drinks, and a walk after meals if the OB agrees.
- The anemia labs. She recommends iron-rich foods the surrogate actually likes, pairings that improve absorption, and timing for any supplement the OB prescribes.
- Probiotics and digestion, which often come up with iron supplements.
- Delivery preparation: eating well in the last weeks, easy meals for recovery and, if she plans to pump, preparing for the extra calories and fluid that making milk takes.
Julie coordinates with the OB when a lab needs action. The OB makes the medical decisions. Julie turns them into a plan the surrogate can follow at home.
How do results affect delivery planning and the parents?
Most surrogates with normal results, or with gestational diabetes controlled by diet, follow an ordinary delivery plan.
Results can change the plan in a few ways. If gestational diabetes needs medication, the OB may add monitoring in the last weeks and may discuss the timing of delivery. If the baby is measuring large, the OB discusses the safest way to deliver; the C-section and recovery page explains what happens if a cesarean is needed. After birth, the hospital checks the newborn's blood sugar, which parents should expect when gestational diabetes was present.
Anemia matters for delivery because every birth involves some blood loss. Better iron stores going in mean an easier recovery afterward, and more energy if she pumps. The options for pumping are on the lactation and milk donation page.
For intended parents: these are routine tests, abnormal results are common, and the care that follows is well established. You hear about results through the communication plan agreed at matching. Decisions about the surrogate's care belong to her and her OB.
What other third-trimester labs and tests are done?
The glucose screen and blood count are two of several routine checks late in pregnancy. Practices vary, and the OB sets the schedule.
| Test | Timing in weeks | What is measured | Typical cutoff | Follow-up | Who reviews |
|---|---|---|---|---|---|
| Glucose challenge test | 24 to 28 | Blood sugar one hour after a 50-gram drink | Commonly 130 to 140 mg/dL | Three-hour glucose tolerance test if positive | OB; Julie at consult 5 |
| Three-hour glucose tolerance test | After a positive screen | Fasting blood sugar, then at one, two and three hours after 100 grams | Two or more values above the practice's cutoffs | Diet plan, home blood sugar checks, medication if needed | OB; Julie builds the meal plan |
| Complete blood count | Often at 24 to 28, with the glucose screen | Hemoglobin and red blood cells | Hemoglobin under 11 g/dL | Iron-rich foods, supplements | OB; Julie at consult 5 |
| Antibody screen | About 28, if her blood type is Rh negative | Antibodies to the baby's blood type | Set by the lab | An Rh immune globulin shot if indicated | OB |
| Group B strep swab | 36 to 37 | A common bacteria in the vagina and rectum | Positive or negative | Antibiotics during labor if positive | OB and hospital |
| Blood pressure and urine | Every prenatal visit | Signs of preeclampsia | Set by the OB | More monitoring if raised | OB |
PLS tracks the pregnancy through the surrogate's case manager after the fertility clinic releases her to her OB, a step explained on the early ultrasounds and OB release page. For the full range of support, see surrogate support.
This page gives general information. It is not medical advice. The surrogate's OB orders and interprets every test.
Sources
- ACOG (American College of Obstetricians and Gynecologists), practice guidance on gestational diabetes and on anemia in pregnancy. https://www.acog.org/
- CDC (Centers for Disease Control and Prevention), information on gestational diabetes. https://www.cdc.gov/