Should You Be Worried About Weight Gain During Pregnancy?
Pregnancy is a beautiful time to fall in love with your body. You’re growing a human (or two!), but with that joy often comes anxiety about weight gain. You might be wondering:
“Am I gaining enough weight?”
“Am I gaining too much?”
“Does eating for two (or three) mean I should just listen to my cravings?”
As a prenatal dietitian, I know firsthand how confusing this can be. Cravings, aversions, nausea and fatigue can make it hard to eat consistently, let alone meet weight gain goals. But healthy pregnancy weight gain is important, both too much and too little can come with risks for you and your baby (or babies).
In this post, you’ll learn:
The risks of gaining too much weight
The risks of gaining too little weight
General weight gain recommendations
How twin pregnancy changes the picture
Nutrition strategies for healthy weight gain
Risks of Gaining Too Much Weight
You’ve probably heard “you’re eating for two!” but in reality, nutrition during pregnancy is about quality over quantity. Excessive weight gain is associated with:
Gestational diabetes: Women with a high BMI are up to 9x more likely to develop GDM.
Preeclampsia: Risk is tripled in women with a BMI >30 due to inflammation and insulin resistance.
C-section delivery: Higher rates due to surgical complications and anesthesia risks.
Miscarriage: Women with obesity nearly double their risk compared to women with a healthy BMI.
Neural tube defects: Higher BMI is linked to increased folate needs.
Preterm birth: Overweight and obese women are 30% more likely to deliver early; the risk is even higher for very preterm birth (<32 weeks).
Risks of Gaining Too Little Weight
On the flip side, inadequate weight gain also carries risks, including:
Low birth weight (LBW): Babies born too small face higher lifetime risks of type 2 diabetes, heart disease, and obesity.
Childhood obesity risk: Poor fetal growth may disrupt hunger/fullness regulation.
Infant mortality: Underweight women with low weight gain face a 6x higher risk.
Critical first trimester: Weight gain early in pregnancy strongly predicts newborn size.
Singleton Pregnancy Weight Gain Recommendations
Underweight BMI (<18.5): 28-40 lbs
Healthy BMI (18.5–24.9): 25–35 lbs
Overweight BMI (25–29.9): 15–25 lbs
Obese BMI (30+): 11–20 lbs
Twin Pregnancy Weight Gain Recommendations
If you’re carrying twins, your weight gain needs are higher than a singleton pregnancy. Proper weight gain is one of the strongest predictors of longer gestation and healthy birthweights in twins.
Underweight BMI (<20): 50-66 lbs*
Normal BMI (20-24.9): 40-56 lbs
Overweight BMI (25-29.9): 38-47 lbs
Obese BMI (30+): 31-36 lbs
Twin pregnancies also often require earlier weight gain, especially in the first and second trimester, to support faster fetal growth and reduce the risk of preterm birth. Meeting these needs can feel challenging — especially with nausea, heartburn, or fatigue — but having a clear plan makes all the difference.
*Although a BMI of 20 is considered normal, research shows that women pregnant with twins with a lower BMI benefit from additional weight gain.
Nutrition Strategies for Healthy Weight Gain
As a prenatal dietitian, I don’t believe in obsessing over numbers on the scale. Instead, I use weight as one tool to guide nutrition interventions. With my clients, I focus on:
Estimating energy needs
Reviewing dietary patterns
Identifying gaps in protein, folate, iron, calcium and omega-3s
Offering practical meal and snack ideas that fit real life
Monitoring weight trends compassionately and without judgment
Remember: it’s not about “perfect” eating, it’s about giving your body and babies the steady fuel they need.
The Bottom Line
Healthy weight gain during pregnancy (especially in a twin pregnancy) can make a real difference for birth outcomes. While too much or too little gain comes with risks, focusing on balanced nutrition and steady growth is key. If you’re feeling overwhelmed, you don’t have to figure it out alone. Working with a prenatal dietitian can give you the tools, confidence and support you need. Want more help? My signature program, the Twice Nourished Nutrition Program was designed specifically for twin pregnancies to guide you through nutrition, prevent complications and help you feel confident in your food choices. Learn more here.
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