Should You Be Worried About Weight Gain During Pregnancy?
By Annie Gager, MS, RD
December 6th, 2024
So how important is weight gain during pregnancy? Pregnancy is a beautiful time to fall in love with your body. You are growing a human, but with that joy and excitement might come anxiety.
You may be thinking… “Am I gaining enough weight?” “Am I gaining too much weight?” “I’m not worried about weight gain, I’m eating for two!”
During pregnancy, cravings, food aversions, changes in taste buds, and morning sickness can make eating anything at all really difficult for moms. So to worry about weight gain is probably not at the forefront of your thoughts during the first trimester. But as I can imagine (because you are here reading this article) you are probably curious if you should be worried about gaining too little or too much weight during pregnancy.
Well as a prenatal dietitian, I am here to tell you there are some very possible pregnancy complications that come along with gaining too little or too much weight during pregnancy. As a dietitian who supports mindful eating habits, weight or calories are not the foundation of my sessions with clients, but instead I use it as a tool to help better understand my clients and provide thorough nutrition interventions.
Keep reading and you’ll learn the risks of gaining too much weight, gaining too little weight, general recommendations for weight gain and how to implement nutrition to support your weight goals for a healthy pregnancy.
Too Much Weight Gain
Your mom or friend or grandma may be telling you to eat more because you are “eating for two." But this really should not be how we are eating or viewing food in pregnancy. If we take a look at normal weight gain for pregnancy, it varies different from person to person. It depends on pre-pregnancy weight, single pregnancy or multiples, weight gain per trimester, and the various stages of each trimester.
Excessive weight gain during pregnancy is associated with an increased risk of developing:
Gestational diabetes: Women with an obese BMI are 9x more likely to develop gestation diabetes compared to women of a healthy BMI. (1)
Preeclampsia: Prevalence is tripled in women with a BMI >30 due to increased insulin resistance and inflammation. (2)
Need for a C-section: C-sections increase surgical risks due to the greater need for anesthesia and increased risk of developing DVT’s or blood clots. (3)
Miscarriage: A study of more than 40,000 pregnant women found that women who were classified as obese has nearly double the chance of miscarriage. (4)
Neural tube defects: Women with an obese BMI have increased folate requirements which increases as BMI increases. (5-7)
Preterm birth: Women who are overweight or obese have a 30% greater risk of giving birth before 37 weeks. Additionally, women who are obese 82% more likely to have pre-term birth prior to 32 weeks compared to women with a normal BMI. (8)
I promise you, I am not at all trying to scare you but instead relay the information that is truly needed to understand the importance of normal weight gain during pregnancy. As with anything in life, the opposite end of the spectrum also has its consequences. Too little weight gain during pregnancy comes with its own risk.
Too Little Weight Gain
Inadequate weight gain during pregnancy is associated with an increased risk of:
Low birthweight baby (LBW): Children born to women exposed to famine, struggled with an ED or severe inadequate weight gain have a greater risk of developing type 2 diabetes, heart disease, obesity and renal dysfunction 40-50 years later. (9-11)
Childhood obesity: Although the research is not conclusive, it is believed that babies born underweight can have an underdeveloped part of their brain that controls hunger/fullness cues resulting in excessive weight gain later in life. (12)
Infant mortality: Women who are considered underweight prior to getting pregnancy and had inadequate weight gain during pregnancy have 6 times the risk of infant mortality than compared to women with a healthy BMI and adequate weight gain. (13)
Interestingly enough, weight gain during the first trimester strongly influences new-born size more than weight gain in the second or third trimester. Closely monitoring weight gain during the first trimester is a crucial intervention in reducing risk of low/high birth weight. (14)
So… how much weight should you gain during your pregnancy?
In the first trimester, weight gain primarily consists of fat stores, fluid and increased blood volume. It is recommended women gain no more than 4.4 pounds during the first trimester as the baby is only about the size of a plum.
After the first trimester, weight gain should increase by about 0.5-1 pound per week, but may vary depending on the recommended amount of weight gain.
A women with a healthy BMI (18.5-25) should be aiming to gain between 25-35 pounds during her pregnancy.
Women with an overweight BMI (25-30) prior to pregnancy should gain anywhere between 15-25 pounds during her pregnancy.
Women with an obese BMI (30+) should be aiming to gain anywhere from 0-20 pounds during their pregnancy.
All of these recommendations will vastly vary from person to person so it is not a one-size fits all. As always, these are general guidelines and I recommend always seeking medical advice from your healthcare provider or Registered Dietitian. The next steps I take working with my clients to support adequate weight gain during pregnancy is to: calculate estimated energy needs, complete a full dietary analysis, estimate daily caloric intake, review micronutrient needs and provide evidence-based recommendations to support adequate weight gain for my clients.
It is important to understand the benefits and risks of pregnancy weight gain, but not to obsess on the number on the scale. At the end of the day, all you can do is your best. Seeing a pregnancy dietitian (like myself) will help your have the right tools and resources to support healthy weight gain during pregnancy. We are here as your support, providing compassionate and non-judgmental care. We want what is best for you and your baby!
Click here to book your initial nutrition consultation! I can’t wait to meet you.
— Annie
References:
Nitert MD, Foxcroft KF, Lust K, Fagermo N, Lawlor DA, O'Callaghan M, et al. Overweight and obesity knowledge prior to pregnancy: a survey study. BMC Pregnancy Childbirth. 2011;11:96.
Roberts JM, Bodnar LM, Patrick TE, Powers RW. The role of obesity in preeclampsia. Pregnancy Hypertension: An International Journal of Women's Cardiovascular Health. 2011;1(1):6-16.
Sebire NJ, Jolly M, Harris JP, Wadsworth J, Joffe M, Beard RW, et al. Maternal obesity and pregnancy outcome: a study of 287 213 pregnancies in London. International Journal of Obesity. 2001;25(8):1175-82.
Tennant PW, Rankin J, Bell R. Maternal body mass index and the risk of fetal and infant death: a cohort study from the North of England. Human reproduction (Oxford, England). 2011;26(6):1501-11.
Leddy MA, Power ML, Schulkin J. The impact of maternal obesity on maternal and fetal health. Rev Obstet Gynecol. 2008;1(4):170-8.
Rasmussen SA, Chu SY, Kim SY, Schmid CH, Lau J. Maternal obesity and risk of neural tube defects: a metaanalysis. Am J Obstet Gynecol. 2008;198(6):611-9.
Huang HY, Chen HL, Feng LP. Maternal obesity and the risk of neural tube defects in offspring: A meta-analysis. Obesity research & clinical practice. 2017;11(2):188-97.
McDonald SD, Han Z, Mulla S, Beyene J. Overweight and obesity in mothers and risk of preterm birth and low birth weight infants: systematic review and meta-analyses. 2010;341:c3428.
Organisation WH. Feto-maternal nutrition and low birth weight 2020 [Available from: https://www.who.int/nutrition/topics/feto_maternal/en/.
Roseboom T, de Rooij S, Painter R. The Dutch famine and its long-term consequences for adult health. Early human development. 2006;82(8):485-91.
Davies PSW, Funder J, Palmer DJ, Sinn J, Vickers MH, Wall CR. Early life nutrition and the opportunity to influence long-term health: an Australasian perspective. Journal of Developmental Origins of Health and Disease. 2016;7(5):440-8.
Shin B-C, Dai Y, Thamotharan M, Gibson LC, Devaskar SU. Pre- and postnatal calorie restriction perturbs early hypothalamic neuropeptide and energy balance. J Neurosci Res. 2012;90(6):1169-82.
Davis RR, Hofferth SL, Shenassa ED. Gestational weight gain and risk of infant death in the United States. Am J Public Health. 2014;104 Suppl 1(Suppl 1):S90-S5.
Brown JE, Murtaugh MA, Jacobs DR, Jr., Margellos HC. Variation in newborn size according to pregnancy weight change by trimester. The American Journal of Clinical Nutrition. 2002;76(1):205-9.
