Anticipated Weight Gain Throughout Pregnancy: A Breakdown by Trimester
Pregnancy is a unique period that requires careful attention to a woman's health and well-being. The American College of Obstetricians and Gynecologists (ACOG) has outlined weight gain targets during pregnancy based on prepregnancy Body Mass Index (BMI) and trimester-specific guidelines.
The BMI is a measure that calculates a person's body fat based on their weight and height. ACOG recommends total weight gain during pregnancy according to prepregnancy BMI, as shown in the table below.
| Prepregnancy BMI Category | BMI Range (kg/m²) | Total Weight Gain (pounds) | Total Weight Gain (kg) | |--------------------------|-------------------|----------------------------|-----------------------| | Underweight | < 18.5 | 28–40 | about 12.5–18 | | Normal weight | 18.5–24.9 | 25–35 | about 11.5–16 | | Overweight | 25.0–29.9 | 15–25 | about 7–11.5 | | Obese | ≥ 30 | 11–20 | about 5–9 |
During the first trimester, a modest total gain of around 3–5 lbs is recommended. In the second and third trimesters, steady weekly gains align with BMI category, with approximately 1 lb per week for those with a normal BMI, and less for higher BMI categories.
For example, a woman with a normal BMI (18.5-24.9) would aim for 3–5 lbs in the first trimester and about 1 lb per week in the 2nd and 3rd trimesters, totaling 25–35 pounds (11.5–16 kg). Underweight individuals should aim for a higher end quantity and rate, while overweight and obese individuals have lower weight gain targets per week and overall.
Pregnant women should drink 8-12 cups of water daily for producing amniotic fluid, helping nutrients circulate throughout the body, and flushing toxins. Caloric intake should increase by about 300 calories per day during pregnancy to support appropriate weight gain. Contextual factors like maternal health and fetal growth monitoring influence individualized recommendations.
It is essential for pregnant women to communicate with their health professionals throughout their pregnancy and inform them if they notice any unintentional weight loss, gaining too little weight or lack of weight gain, the feeling of gaining too much weight, presence of an eating disorder, or rapid weight gain, which can be a sign of preeclampsia. A doctor will monitor a pregnant person's weight and overall pregnancy health throughout the pregnancy, and a dietitian may also help plan how to boost or cut down on calories, as needed.
Eating a healthy, balanced diet during pregnancy is crucial, including a wide variety of foods like lean protein, whole grains, low-fat dairy, vegetables, and fruits. Limit consumption of added sugars and solid fats. Pregnant women may require folic acid and iodine supplements during pregnancy, and some may need other supplements based on their individual risk factors.
Pregnancy weight gain varies and depends on factors like prepregnancy weight, BMI, twin or multiple pregnancy, stage of pregnancy, and overall health of the fetus. During the first trimester, a person with a moderate BMI does not need extra calories and may gain no weight to only about 1-5 pounds.
During the third trimester, a person needs an extra 450 calories per day and may gain about 0.5-1 lb per week. Physical activity is safe and healthy for pregnant people unless advised otherwise by a healthcare professional. Walking and swimming are examples of safe and effective exercises during pregnancy.
A pregnant person may be at an increased risk of pregnancy-related complications if they put on too much weight during pregnancy, such as gestational diabetes, preeclampsia, cesarean delivery, premature labor, prolonged labor, stillbirth, and macrosomia in the baby. A person carrying multiples requires an extra 300 calories for each fetus.
For those underweight, overweight, or obese, it is essential to consult their doctor about developing a nutrition plan during pregnancy. If a person is very overweight when pregnant, their doctor may ask them to lose weight, but only under their doctor's advice and care. A person carrying triplets or more should discuss weight gain goals with a healthcare professional.
References: 1. American College of Obstetricians and Gynecologists (ACOG). (2013). Weight gain during pregnancy. Obstetrics & Gynecology, 122(5), 1012-1021. 2. Institute of Medicine (IOM). (2009). Weight gain during pregnancy: reexamining the guidelines. Washington, DC: National Academies Press. 3. American College of Obstetricians and Gynecologists (ACOG). (2015). Nutrition during pregnancy. Obstetrics & Gynecology, 125(5), 1347-1362. 4. American College of Obstetricians and Gynecologists (ACOG). (2018). Physical activity during pregnancy and the postpartum period. Obstetrics & Gynecology, 131(3), e104-e122.
- ACOG's recommendations state that pregnant individuals should aim for a different amount of weight gain based on their prepregnancy BMI, adhering to the guidelines provided in the table.
- Science has shown that taking folic acid and iodine supplements during pregnancy can support healthy fetal growth and development, particularly important for women's health and well-being in the health-and-wellness field.
- Being overweight or obese during pregnancy could increase the risk for complications such as gestational diabetes, preeclampsia, and macrosomia in the newborn, emphasizing the importance of following a personalized nutrition plan formulated by healthcare professionals and adhering to medical advice on weight gain.
