What BMI Do You Need to Be a Surrogate?

BMI is a common reason a strong applicant hears "not yet." Here's where the usual cutoff comes from, what ASRM does and doesn't say, and what to do if you're just over the line.

Published October 13, 2026

Most surrogacy programs look for a BMI under 32, and a few accept up to 35. ASRM's guidance for gestational carriers doesn't set a BMI number itself, so the exact cutoff is a program and clinic policy, and a BMI just over the line is often a "not yet" rather than a "never."

Of all the questions we hear, this one comes with the most hesitation. Women who have carried their own babies without trouble, who are healthy and active, sometimes find out that a single number sits between them and an application. It helps to understand what that number measures, why programs use it, and what you can actually do about it.

What BMI measures

Body mass index is your weight relative to your height. The CDC's adult categories are under 18.5 (underweight), 18.5 to 24.9 (healthy weight), 25 to 29.9 (overweight), and 30 or higher (obesity). The CDC is also clear about its limits: it calls BMI "a screening measure" that is "not intended to diagnose disease or illness," and one health indicator to consider alongside others.

To make the usual cutoffs concrete: for a woman who is 5'5", a BMI of 32 works out to about 192 pounds, and a BMI of 35 to about 210 pounds. At 5'4" those numbers are about 186 and 204 pounds, and at 5'6" about 198 and 217.

Why programs use a cutoff

The reason is your safety in the pregnancy you'd be carrying. The National Institute of Child Health and Human Development (NICHD) lists obesity as a pregnancy risk factor and says it "increases the risk for high blood pressure, preeclampsia, gestational diabetes, stillbirth," neural tube defects and cesarean delivery. As a surrogate, those are risks to your body, so programs and clinics set a line where they're comfortable that a pregnancy is likely to go smoothly.

That's also why a BMI limit isn't a judgment about how you look or how healthy you feel. It's a population-level risk marker, and like any cutoff it's blunt. Two women with the same BMI can be in very different health, which is exactly why the clinic's doctor reviews the whole picture.

What ASRM says, and what it doesn't

ASRM's Practice Committee guidance on gestational carriers says that before acceptance, a potential carrier should undergo a complete medical evaluation by a qualified medical professional, including preconception counseling and evaluation. Its Ethics Committee describes carriers as people who should be healthy, at least 21, with a stable social environment and at least one uncomplicated pregnancy that resulted in a healthy baby.

Neither document sets a BMI number. The figures you'll see, under 32 at most programs and up to 35 at a few, are program and clinic policy. That matters in two ways. First, the cutoff can differ from one program to the next. Second, the IVF clinic that does your medical screening usually has its own limit, and the clinic's doctor makes the final medical decision regardless of what an agency's website says.

If you're over the limit

A BMI above a program's cutoff is an eligibility issue that can change. Plenty of women apply after working toward a goal with their own doctor. A few things are worth knowing before you start:

• Plan it with your doctor, not around a deadline. A steady, sustainable change is better for you than a crash diet before a screening date, and your doctor can tell you what pace is safe.
• Weight-loss medications need a plan. The FDA label for semaglutide tells women to discontinue it at least 2 months before a planned pregnancy "due to the long washout period." If you take semaglutide or a similar medication, tell the program and the clinic, and let your prescriber decide how and when to stop. Never stop or change a medication on your own.
• Weight-loss surgery has its own timeline. ACOG advises waiting 12 to 24 months after bariatric surgery before conceiving, so your weight has stabilized. Clinics typically want your surgical records and may look closely at your nutrition and lab work.
• Expect the number to be checked again. Programs usually want you within their range when you apply and when you're screened, and clinics often recheck before transfer.

BMI and the rest of your application

BMI is one requirement among several, alongside your age, your pregnancy and delivery history, the time since your last delivery, your support at home and where you live. Meeting it doesn't guarantee a match, and missing it by a little doesn't mean the rest of your application doesn't matter. If you're unsure where you stand on any of it, our step-by-step guide walks through the full list.

How Borne handles this

Our questionnaire asks for your height and weight along with your health and pregnancy history. If your BMI is within the range our partner agencies accept, we keep going. If it's over, we'll tell you plainly, explain which programs might have more room, and you can come back when the timing is right. There's no penalty for applying again later.

The bottom line

Under 32 is the most common cutoff and up to 35 is possible at some programs. The number comes from program and clinic policy built around pregnancy risk, not from ASRM. If you're over it, treat it as a "not yet," make a plan with your doctor, and be open with us about where you are.