What Dealing With Fetal Growth Restriction Was Like

Hearing your fetus has fetal growth restriction can be scary. But here's what FGR means and how it can impact pregnancy.

Women looking at her ultrasound photos

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When I was 20 weeks pregnant, my baby was diagnosed with a condition I'd never heard of: fetal growth restriction (FGR), also known as intrauterine growth restriction (IUGR). It meant my baby wasn't growing at an expected rate. The diagnosis was confusing and overwhelming and my pregnancy left a lot to be desired.

With a bright, thriving toddler bouncing on my lap, I can assure you my story has a happy ending. But FGR was a lot to handle, especially because the causes and outcomes can be so varied. 

Here’s what it means to have an FGR diagnosis and how it may impact pregnancy.

What Is Fetal Growth Restriction?

FGR means a fetus isn’t growing as expected in the womb for its gestational age. It’s when the fetus has a weight or abdominal circumference less than the 10th percentile for gestational age.

FGR occurs in up to 10% of pregnancies. Despite it being relatively common, FGR isn’t a condition often discussed, especially in parent groups.

A small baby isn't always an issue in itself—some babies may just be constitutionally small. “About 20% of [fetuses with FGR] will be constitutionally small fetuses that will be healthy at birth with a normal outcome,” says Lynn L. Simpson, M.D., chief of maternal fetal medicine and professor of women's health at Columbia University Irving Medical Center. But FGR can point to issues for some fetuses. 

The condition can have an early or late onset, be considered symmetric (when all of the fetus is similarly small in size) or asymmetric (some parts are smaller than others), and be mild or severe. “FGR is a complex problem that is only unified by its definition,” adds Dr. Simpson.

What FGR Could Mean for Your Pregnancy

When I was diagnosed with FGR, several risks were outlined to me. My maternal fetal medicine (MFM) specialist told me I had a 1 in 3 chance of miscarriage, 1 in 3 chance that my baby could be born with a severe disability, or that my baby could be perfectly healthy. At that early stage, it was too soon to tell.

FGR has been linked to a host of complications, including perinatal morbidity and mortality. It also carries increased risks for low birth weight, issues during delivery, decreased oxygen levels, infection, low blood sugar, and breathing problems. Some studies suggest that FGR can lead to future cognitive development issues or ongoing growth restrictions. 

This can all be scary to hear. But it's important to recognize that outcomes will depend on the cause, although that’s not always easy to determine. It also doesn’t mean your baby will experience such issues by virtue of their FGR diagnosis. It can simply be an indicator. 

“Each case is different—and most importantly, favorable outcomes are possible," says Dr. Simpson. "Following the advice of one's obstetrician and MFM specialist can help optimize the outcome of pregnancies affected by FGR."

FGR Pregnancy Symptoms 

I was told about my FGR diagnosis at my 20-week scan. FGR is typically found after 20 weeks of pregnancy when a health care provider starts measuring the fundal height or the distance from the pubic bone to the top of the uterus. In simpler terms, it’s the height measurement in centimeters of one’s bump. After about 20 weeks, a pregnant person’s fundal height should be about the same as the weeks of pregnancy. So, if someone is 25 weeks, their fundal height should be about 25 centimeters. 

Many times, there will be no physical symptoms to hint at FGR other than perhaps a small bump, but this isn't always indicative of the condition. Prior to my 20-week scan there was no indication that my baby's growth was compromised, although in hindsight my bump was relatively small. This was something I put down to being a first-time mom and it wasn't flagged by medical specialists at this point.

FGR Causes

Sometimes FGR just happens and you'll never know how or why. But there are some risk factors that have been linked to the condition. "FGR can be related to maternal disease, fetal conditions, or placental dysfunction,” explains Dr. Simpson. 

These can include lifestyle choices like smoking or drug abuse, the health of the pregnant person, infections such as toxoplasmosis or cytomegalovirus, or problems with the placenta like placental dysfunction or abruption preventing the fetus from receiving enough nutrients. Chromosomal abnormalities or genetic conditions can also be present in a diagnosis of FGR. 

Angela M. Patterson, M.D. FAAP, a specialist in neonatal and perinatal medicine and board member of the National Perinatal Association, says piecing together these elements can help specialists treat FGR. She says it's beneficial to identify a cause as early as possible. "You might not be able to enhance the growth in and of itself, but you might be able to do something," she adds.

FGR Treatment

Fetuses with FGR will be referred to an MFM specialist whose job is to work out why the growth is restricted and what, if any, impact this has had or could have on the baby. Once FGR is diagnosed, no matter what the findings or cause, health care providers will continue to watch the fetus closely throughout the pregnancy.

Prenatal investigations can include ongoing fetal monitoring to measure growth, as well as to track heart rate and blood flow, screening for infections, and amniocentesis to determine, or rule out, a genetic cause. Parental tests may also be taken to check for high blood pressure or other issues that could be affecting the birthing parent. However, sometimes, these tests will do little to provide further insights, and the impact may never be truly understood, or it may not be clear until the baby arrives or even as they develop.

In some cases, even with regular check-ups, specialists will decide an FGR baby will thrive better on the outside, where the environment for the baby will be less hostile. Dr. Patterson says that’s why some FGR babies will be induced early, and may spend time in the neonatal intensive care unit (NICU). "Sometimes we have no control on the internal environment inside the uterus, but we have a little more control on the environment outside of the uterus," she explains.

Giving Birth to a Baby With FGR

My water broke at 31+6 weeks and our little one arrived eight weeks premature by emergency C-section. My doctors never confirmed what caused my FGR, although there were suspicions that my placenta either didn't implant properly, or had slightly detached during pregnancy. My son spent five weeks in NICU, mostly to build his strength as he was born below the 3rd percentile. Anticipating this was helpful, and I'm grateful to my medical team for preparing me for such outcomes.

After birth, babies who were diagnosed with FGR may face some additional challenges. Post NICU, for example, my son experienced some feeding issues. That’s not uncommon for infants with FGR, as they may have issues tolerating typical feeding volumes once they're born, says Cuyler Romeo, M.O.T., OTR/L, SCFES, IBCLC, a feeding specialist at Feeding Matters

My son also had minor delays with gross motor skills, like crawling and walking, because he needed a bit longer to build his core muscles. But more than once his pediatric team told me he was “bright as a button” and that there was nothing to worry about developmentally. 

By 12 months, he was up to the 9th percentile for weight and a huge 50th for length, making him tall-ish, but slight-ish, and very confidently healthy. Importantly, he continues to follow his growth curve. This is a far cry from the scenarios we were preparing for during our pregnancy, but will hopefully offer some comfort to those who are confused by their diagnosis like I was.

Romeo says although many children who were diagnosed with FGR catch up by the time they are 2 years old, some may need specialized support in different areas to ensure they reach their growth and developmental potential.

"This is not an indication of a future problem or delay, rather even more reason to empower families to seek support so they can make informed choices regarding their child's care," she explains. “They will learn new skills and meet their milestones; they will do so at the rate that works best for their unique body."

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  1. SMFM Consult Series #52: Diagnosis and Management of Fetal Growth Restriction, Society for Maternal-Fetal Medicine

  2. Association of Intrauterine Growth Restriction and Small for Gestational Age Status With Childhood Cognitive Outcomes, JAMA Pediatrics, 2020

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