Why Am I Not Gaining Weight During Pregnancy? Causes & Solutions

Quick take: Not gaining weight during pregnancy can feel worrying, but it’s not always a cause for concern. In the first trimester, many women lose or maintain weight due to nausea, and some may even gain less than expected later on. However, very low weight gain—especially in the second and third trimesters—can sometimes signal an underlying issue or affect your baby’s growth. The key is to focus on eating nutrient-dense foods, tracking your progress with your provider, and seeking help if you notice red flags like persistent nausea, fatigue, or your baby’s movements slowing down.

You step on the scale at your prenatal checkup, bracing yourself for the number. Again, it hasn’t budged—or worse, it’s dropped. Your mind races: Is my baby getting enough? Am I doing something wrong? Should I be eating more? If this sounds familiar, you’re not alone. Many women spend pregnancy hyper-aware of every pound, and when the scale doesn’t cooperate, it can feel like a personal failure.

Here’s the truth: weight gain in pregnancy isn’t one-size-fits-all. Some women gain steadily, while others plateau or even lose weight early on. What matters most isn’t the number on the scale, but whether you and your baby are getting the nutrients you need. Still, it’s natural to wonder: When is low weight gain normal, and when should I be concerned?

In this guide, we’ll walk through what’s typical, what might be causing your weight to stall, and when to reach out to your provider. You’ll find practical tips for nourishing yourself (even when food feels impossible), a clear breakdown of risks, and answers to the questions keeping you up at night. Let’s start with what’s actually happening in your body—and why the scale might not be telling the whole story.

Why Am I Not Gaining Weight in My Second Trimester?

The second trimester is often called the "honeymoon phase" of pregnancy—nausea fades, energy returns, and many women start to feel like themselves again. So when the scale still doesn’t move, it can feel like a letdown. If this is you, take a deep breath: it’s more common than you think.

For some women, weight gain in the second trimester is slow because their bodies are still catching up from the first trimester. If you lost weight early on due to morning sickness or food aversions, your body might prioritize replenishing your own stores before adding baby weight. Others simply have a faster metabolism, especially if they’re active or naturally petite. And let’s be honest: pregnancy hunger isn’t a guarantee. Some women still struggle with appetite, especially if they’re dealing with heartburn, bloating, or stress.

One reader, Sarah, described her second trimester like this: "I was finally eating normally again, but the scale barely moved. My midwife told me not to stress—as long as my baby was growing on the ultrasound, we were on track. Turns out, my body just needed time to adjust."

That said, if you’re not gaining any weight by the mid-second trimester (around 20 weeks), or if you’re losing weight, it’s worth checking in with your provider. They can rule out issues like hyperemesis gravidarum (severe pregnancy nausea) or thyroid problems, and help you make a plan to support your baby’s growth.

What’s "Normal" Weight Gain in the Second Trimester?

Most guidelines suggest gaining about 1 pound per week in the second trimester, but this is a rough estimate. The American College of Obstetricians and Gynecologists (ACOG) notes that weight gain varies widely, and some women gain more slowly without any issues. Here’s a general breakdown:

Remember: these are averages. If you’re gaining less but your baby is growing well on ultrasounds, your provider will likely reassure you. The goal isn’t to hit a specific number, but to ensure you’re both thriving.

When to Talk to Your Provider

While slow weight gain isn’t always a problem, there are a few signs that warrant a conversation with your doctor or midwife:

• You’re not gaining any weight by 20 weeks (or losing weight).
• You’re struggling to keep food down due to nausea or vomiting.
• You feel weak, dizzy, or fatigued all the time.
• Your baby’s movements have slowed or changed.
• You have other symptoms like rapid heartbeat, excessive thirst, or swelling (which could signal thyroid issues or other conditions).

If any of these sound familiar, don’t wait for your next appointment. A quick check-in can give you peace of mind—or help you catch and address an issue early.

Can I Be Healthy If I Don’t Gain Weight During Pregnancy?

First, let’s talk about the women who can have healthy pregnancies with little to no weight gain. These often include:

• Women who started pregnancy overweight or obese. The Institute of Medicine (IOM) notes that women with a higher pre-pregnancy BMI may need to gain less weight—or even lose a small amount—without harming their baby. In fact, gaining too much weight in this group can increase risks like gestational diabetes or preeclampsia.
• Women with hyperemesis gravidarum (HG). If you’re vomiting multiple times a day and struggling to keep food down, your body may prioritize your baby’s needs over your own weight. With proper medical support (like IV fluids or anti-nausea medication), many women with HG deliver healthy babies despite minimal weight gain.
• Women who are naturally petite or have a high metabolism. Some bodies simply don’t store extra weight easily, even during pregnancy. As long as you’re eating enough nutrients and your baby is growing well, your provider will likely monitor you closely but not push for weight gain.

One mom, Priya, shared her experience: "I barely gained 10 pounds my entire pregnancy. My doctor wasn’t worried because my baby was measuring right on track, and I was eating well. She told me, ‘Some women are just built differently—and that’s okay.’"

On the other hand, low weight gain can be a red flag if it’s due to:

• Poor nutrition. If you’re not eating enough calories or nutrients (due to food aversions, stress, or lack of access to food), your baby may not get the building blocks they need for healthy development.
• Underlying medical conditions. Thyroid disorders, digestive issues (like celiac disease or Crohn’s), or infections can interfere with weight gain and nutrient absorption.
• Excessive exercise. While staying active is great, overdoing it (like intense cardio daily) can burn more calories than you’re taking in, especially if you’re not adjusting your diet.

How Low Weight Gain Affects Your Baby

Research shows that very low weight gain (or weight loss) in pregnancy is linked to a higher risk of:

• Low birth weight (under 5.5 lbs). Babies born small are more likely to have trouble with feeding, temperature regulation, and long-term health issues like developmental delays.
• Preterm birth. A 2020 study in JAMA Pediatrics found that women with low weight gain were more likely to deliver before 37 weeks.
• Neonatal intensive care (NICU) stays. Babies who don’t grow well in the womb may need extra support after birth.

That said, it’s not all or nothing. Many women with low weight gain deliver healthy, full-term babies. The risks depend on how much weight you’re not gaining, when in pregnancy it happens, and whether you’re getting enough nutrients. For example, low weight gain in the third trimester (when your baby is doing most of their growing) is riskier than in the first trimester.

What Matters More Than the Scale

Instead of fixating on pounds, focus on these signs that you and your baby are doing well:

• Your baby’s growth on ultrasounds. Your provider will track your baby’s size at appointments. If they’re growing steadily (even if you’re not), that’s a great sign.
• Your energy levels. Do you feel strong enough to go about your day? Are you sleeping well? Fatigue is normal in pregnancy, but extreme exhaustion can signal a problem.
• Your baby’s movements. By the third trimester, you should feel regular kicks and rolls. A sudden decrease in movement is always a reason to call your provider.
• Your overall health. Are you hydrated? Are your blood pressure and blood sugar levels normal? These are better indicators of well-being than the scale.

If you’re eating a balanced diet, staying hydrated, and your baby is growing, try to give yourself grace. Pregnancy isn’t a competition, and your body knows how to prioritize your baby’s needs—even when the scale doesn’t show it.

Low Weight Gain in Pregnancy: Symptoms and Risks

If you’re not gaining weight during pregnancy, your body might be sending you signals that something’s off. Some symptoms are subtle, while others are hard to ignore. Knowing what to watch for can help you decide when to seek help—and when to relax.

Symptoms of Low Weight Gain

These signs don’t always mean there’s a problem, but they’re worth paying attention to:

• Persistent nausea or vomiting. Occasional morning sickness is normal, but if you’re throwing up multiple times a day or can’t keep food down for more than 24 hours, it could lead to dehydration and weight loss.
• Fatigue that doesn’t improve with rest. Pregnancy is tiring, but if you’re exhausted all the time—even after a full night’s sleep—it could signal a nutrient deficiency or thyroid issue.
• Dizziness or lightheadedness. This can happen if you’re not eating enough, especially if you’re also dehydrated. Low blood sugar or low blood pressure can make you feel woozy.
• Frequent headaches. While headaches can have many causes, they’re sometimes linked to dehydration or low blood sugar—both of which can go hand-in-hand with low weight gain.
• Constipation or diarrhea. Digestive issues can make it hard to eat enough or absorb nutrients. Chronic diarrhea, in particular, can lead to weight loss and dehydration.
• Food aversions that limit your diet. If you’re avoiding entire food groups (like proteins or carbs) due to nausea or texture issues, you might not be getting enough calories or nutrients.
• Your clothes feel looser. If your waistbands are suddenly baggy or your rings are slipping off, it could be a sign you’re losing weight unintentionally.

One mom, Lisa, noticed her energy plummeting in her second trimester: "I was so tired I could barely get through the day. My doctor checked my iron levels and found I was severely anemic. Once we treated that, I started gaining weight—and feeling like myself again."

Risks of Low Weight Gain

While some women have healthy pregnancies with minimal weight gain, very low weight gain (or weight loss) can pose risks for both you and your baby. Here’s what the research says:

Risks to You

• Nutrient deficiencies. If you’re not eating enough, you might not get enough iron, folate, calcium, or other nutrients critical for your health. This can lead to anemia, bone loss, or fatigue.
• Weakened immune system. Pregnancy already puts extra demands on your body. Not getting enough calories or nutrients can make you more susceptible to infections.
• Muscle loss. If your body isn’t getting enough calories, it may start breaking down muscle for energy. This can leave you feeling weak and make it harder to recover after delivery.
• Increased risk of complications. Some studies link low weight gain to a higher risk of preterm labor or preeclampsia, though the evidence isn’t conclusive.

Risks to Your Baby

• Low birth weight. Babies born weighing less than 5.5 pounds are at higher risk for breathing problems, infections, and developmental delays. A 2019 study in Obstetrics & Gynecology found that women with low weight gain were twice as likely to have a low-birth-weight baby.
• Preterm birth. Babies born before 37 weeks may need extra support to breathe, eat, and stay warm. Low weight gain is one of several factors that can increase this risk.
• Poor growth in the womb. If your baby isn’t getting enough nutrients, they may grow more slowly than expected. This is called intrauterine growth restriction (IUGR), and it can lead to complications during delivery or after birth.
• Long-term health risks. Some research suggests that babies born small may be at higher risk for conditions like diabetes, heart disease, or obesity later in life. However, these risks depend on many factors, and not all small babies will have long-term issues.

It’s important to note that these risks are more likely if you’re not gaining any weight at all or if you’re losing weight. If you’re gaining some weight—even if it’s less than the guidelines—your baby may still be growing well. Your provider will monitor your baby’s size with ultrasounds and adjust your care plan as needed.

When to Worry (and When to Relax)

Not all low weight gain is cause for concern. Here’s how to tell the difference:

If you’re ever unsure, err on the side of checking in with your provider. A quick conversation can give you peace of mind—or help you catch and address an issue early.

What Causes Lack of Weight Gain in Early Pregnancy?

The first trimester is notorious for throwing curveballs—nausea, exhaustion, food aversions—all of which can make it hard to eat, let alone gain weight. In fact, it’s normal to lose a few pounds (or stay the same) in the first 12 weeks. But what’s behind this weight rollercoaster, and when should you be concerned?

The Usual Suspects: Why You Might Not Be Gaining

Here are the most common reasons for low weight gain (or weight loss) in early pregnancy:

1. Morning Sickness (or All-Day Sickness)

Up to 70% of pregnant women experience nausea and vomiting in the first trimester. For some, it’s mild and manageable. For others, it’s severe enough to interfere with eating and drinking. If you’re throwing up frequently, you might not be keeping enough food down to gain weight—and you could even lose a few pounds.

One mom, Emma, described her first trimester like this: "I couldn’t even look at food without feeling sick. I lived on crackers and ginger ale for weeks. By my 12-week appointment, I’d lost 5 pounds. My doctor wasn’t worried because my baby was growing fine, but I was relieved when the nausea finally lifted."

2. Food Aversions

Pregnancy can turn your favorite foods into your worst enemies. Suddenly, the smell of coffee, meat, or even vegetables might make you gag. If you’re avoiding entire food groups (like proteins or carbs), you might not be getting enough calories or nutrients to gain weight.

3. Fatigue

Growing a baby is exhausting, and many women find themselves too tired to cook or eat full meals in the first trimester. If you’re napping instead of eating, or grabbing quick (but not nutritious) snacks, you might not be taking in enough calories.

4. Increased Metabolism

Your body is working overtime to support your baby’s early development, and that can rev up your metabolism. Some women burn more calories than they’re taking in, especially if they’re still active or have a naturally fast metabolism.

5. Stress or Anxiety

Pregnancy can be an emotional time, and stress can suppress your appetite or make it hard to eat. If you’re feeling overwhelmed, you might skip meals or forget to eat—leading to weight loss or stagnation.

6. Digestive Issues

Hormonal changes can slow down your digestion, leading to constipation, bloating, or heartburn. These issues can make it uncomfortable to eat, or they might make you feel "full" even when you haven’t eaten enough.

When to Worry in the First Trimester

While low weight gain (or even weight loss) is common in the first trimester, there are a few red flags to watch for:

• You’re losing more than 5% of your pre-pregnancy weight. For example, if you weighed 150 pounds before pregnancy, losing more than 7.5 pounds could be a sign of hyperemesis gravidarum (severe pregnancy nausea).
• You can’t keep any food or liquids down for more than 24 hours. This can lead to dehydration, which is dangerous for you and your baby.
• You feel weak, dizzy, or lightheaded all the time. These could be signs of dehydration or low blood sugar.
• You’re not urinating as often as usual. This can be a sign of dehydration.
• You have other symptoms like rapid heartbeat, excessive thirst, or dark urine. These could signal an underlying issue like a thyroid disorder or infection.

If any of these sound familiar, call your provider. They can check for dehydration, nutrient deficiencies, or other issues—and help you find relief.

How to Support Your Body (Even When Food Feels Impossible)

If you’re struggling to eat in the first trimester, focus on small, frequent meals and foods that are easy to tolerate. Here are some tips to help you get the nutrients you need:

• Eat what you can, when you can. If crackers and ginger ale are the only things that stay down, that’s okay. The goal is to keep something in your stomach.
• Try bland, easy-to-digest foods. Think toast, rice, bananas, applesauce, or broth. These are gentle on your stomach and less likely to trigger nausea.
• Stay hydrated. Sip water, herbal tea, or electrolyte drinks throughout the day. If plain water makes you nauseous, try adding a slice of lemon or ginger.
• Avoid triggers. If the smell of cooking meat or coffee makes you gag, steer clear. Eat cold foods (like sandwiches or salads) if hot foods bother you.
• Take your prenatal vitamin at night. Some women find that taking their vitamin in the morning makes nausea worse. Try taking it before bed instead.
• Rest as much as you can. Fatigue can make nausea worse, so listen to your body and nap when you need to.

Remember: the first trimester is temporary. Most women start feeling better by week 12 or 14, and their appetite (and weight gain) picks up in the second trimester. Hang in there—you’ve got this.

How Many Pounds Should I Gain Each Week If I’m Not Gaining Weight?

If the scale isn’t moving, you might wonder: How much should I aim for each week? Is there a "magic number" that means I’m on track? The answer depends on your pre-pregnancy weight, your trimester, and how your baby is growing. Let’s break it down.

General Guidelines for Weekly Weight Gain

The Institute of Medicine (IOM) provides these general recommendations for weekly weight gain during pregnancy:

These are averages, not strict rules. Some weeks you might gain more, some weeks less—and that’s okay. What matters most is that you’re gaining some weight over time, and that your baby is growing well on ultrasounds.

What If I’m Not Gaining at All?

If you’re not gaining any weight (or you’re losing weight) in the second or third trimester, your provider will likely want to investigate. Here’s what they might check:

• Your baby’s growth. An ultrasound can measure your baby’s size and estimate their weight. If they’re growing steadily, your provider may not be concerned.
• Your diet. They might ask you to track what you’re eating for a few days to see if you’re getting enough calories and nutrients.
• Your symptoms. They’ll ask about nausea, vomiting, fatigue, or other issues that could be affecting your appetite or digestion.
• Your overall health. They might run blood tests to check for anemia, thyroid issues, or infections.

Based on what they find, they might recommend:

• Adjusting your diet. Adding more calorie-dense foods (like nuts, avocados, or full-fat dairy) can help you gain weight without eating more volume.
• Treating underlying issues. If you have hyperemesis gravidarum, they might prescribe anti-nausea medication. If you have a thyroid disorder, they’ll help you manage it.
• Monitoring your baby more closely. If your baby’s growth is slowing, they might schedule more frequent ultrasounds or non-stress tests to keep an eye on things.

What If I’m Gaining Too Slowly?

If you’re gaining weight, but not as much as the guidelines suggest, your provider will likely focus on two things:

1. Your baby’s growth. If your baby is measuring on track, they may not be concerned.
2. Your overall health. If you’re feeling well and your blood work looks good, they may not push for more weight gain.

That said, if you’re gaining very slowly (like 0.1–0.2 pounds per week in the second or third trimester), they might suggest:

• Adding more calories. Aim for an extra 200–300 calories per day (the equivalent of a small snack, like a banana with peanut butter).
• Focusing on nutrient-dense foods. Choose foods that pack a lot of calories and nutrients into small portions, like nuts, cheese, or smoothies.
• Reducing stress. Stress can suppress your appetite. Try relaxation techniques like deep breathing, prenatal yoga, or talking to a therapist.

What If I’m Gaining Too Quickly After a Slow Start?

If you’ve had a slow start but suddenly start gaining weight quickly, don’t panic. Your body might just be catching up. However, rapid weight gain (more than 2–3 pounds per week) can sometimes signal an issue like gestational diabetes or preeclampsia. If this happens, your provider might:

• Check your blood sugar. Gestational diabetes can cause rapid weight gain, especially in the third trimester.
• Monitor your blood pressure. Preeclampsia (a serious pregnancy complication) can cause sudden weight gain due to fluid retention.
• Adjust your diet. They might suggest reducing processed foods, sugars, or excess salt to help manage your weight.

How to Track Your Weight Gain

If you’re worried about your weight, tracking it can help you spot trends and ease your mind. Here’s how to do it:

• Weigh yourself at the same time each week. Use the same scale, and weigh yourself first thing in the morning (after peeing but before eating).
• Record your weight in a journal or app. This can help you see patterns over time. Some apps, like Ovia or What to Expect, have pregnancy weight trackers built in.
• Don’t obsess over the number. Weight fluctuates daily due to hydration, digestion, and other factors. Focus on the trend over weeks, not day-to-day changes.
• Share your concerns with your provider. If you’re not gaining weight (or gaining too much), they can help you figure out why and make a plan.

Remember: the scale is just one tool. Your provider will use ultrasounds, blood tests, and your overall health to get the full picture. If you’re eating well and your baby is growing, try not to stress about the number.

Diet Tips for Pregnant Women Who Aren’t Gaining Weight

If you’re not gaining weight during pregnancy, your diet might need a little tweaking. But here’s the good news: you don’t have to force yourself to eat huge meals or choke down foods you hate. Small, strategic changes can help you add calories and nutrients without feeling overwhelmed. Here’s how to do it.

Focus on Calorie-Dense Foods

When you’re not gaining weight, the goal is to pack more calories into smaller portions. This way, you can eat less volume but still get the energy you need. Here are some calorie-dense foods to add to your diet:

• Healthy fats: Avocados, nuts (almonds, walnuts, cashews), nut butters, seeds (chia, flax, pumpkin), olive oil, and full-fat dairy (whole milk, cheese, yogurt).
• Complex carbs: Whole grains like oats, quinoa, brown rice, and whole-wheat bread. These provide steady energy and fiber.
• Proteins: Lean meats, poultry, fish, eggs, beans, lentils, and tofu. Protein helps your baby grow and keeps you full.
• Dried fruits: Dates, raisins, apricots, and figs. These are packed with calories and natural sugars for quick energy.
• Smoothies: Blend milk or yogurt with fruit, nut butter, and a handful of spinach for a nutrient-packed drink. Add a scoop of protein powder for extra calories.

One mom, Maria, shared her go-to snack: "I kept a bag of trail mix in my purse—nuts, seeds, and dried fruit. It was easy to nibble on throughout the day, and it helped me add calories without feeling stuffed."

Eat Small, Frequent Meals

If big meals feel overwhelming, try eating smaller portions more often. Aim for 5–6 "mini-meals" or snacks throughout the day. This can help you take in more calories without feeling too full or nauseous. Here’s a sample schedule:

Time	Meal/Snack Idea	Calories (Approx.)
7:00 AM	Greek yogurt with granola and honey	250
10:00 AM	Hard-boiled egg and whole-grain toast with avocado	300
1:00 PM	Grilled chicken wrap with hummus and veggies	400
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