Is Weight Loss Normal in Early Pregnancy? Understanding Causes and Concerns

Losing weight during pregnancy can raise concerns, as adequate weight gain is typically associated with a healthy developing baby. Generally, intentionally losing weight while pregnant is not recommended because it can deprive both you and your baby of essential nutrients. However, many expectant mothers wonder: Is Weight Loss Normal In Early Pregnancy? For some, experiencing a slight drop in weight during the first trimester can be a normal occurrence due to various factors, though significant or prolonged weight loss always warrants discussion with a healthcare provider.

Why Intentional Weight Loss During Pregnancy Is Generally Unsafe

Regardless of your starting weight, deliberately trying to lose weight during pregnancy is not considered safe, with the potential exception of some minor, unintentional loss in the very early weeks. Experts continue to study the complex relationship between maternal weight changes and fetal health, but current understanding indicates that active weight loss isn’t conducive to supporting optimal fetal growth. Dieting or restricting calories could mean missing out on vital nutrients necessary for your baby’s development and your own well-being.

Furthermore, while carrying excess weight during pregnancy is linked to certain complications, attempting to lose weight can introduce different risks, such as having a baby who is small for their gestational age (SGA) or increasing the likelihood of preterm birth.

Is Weight Loss Normal in Early Pregnancy? Common Causes

Experiencing some weight loss in the first trimester can be perfectly normal and is often attributed to:

• Morning Sickness: Nausea and vomiting, common symptoms in early pregnancy collectively known as morning sickness, can significantly reduce appetite and lead to calorie loss. In most cases, this temporary weight dip doesn’t harm the baby, who will still receive the necessary nutrients during this early stage.
• Utilizing Fat Reserves: Women who start pregnancy overweight have additional calorie reserves stored as fat. As the baby begins to grow, drawing on these reserves might lead to maintaining or even slightly losing weight initially without adverse effects.
• Lifestyle Improvements: Sometimes, weight loss occurs simply because pregnancy motivates healthier habits. Adopting a more nutritious diet or starting a safe exercise routine can naturally lead to shedding a few pounds early on.

In most instances, this early weight loss is not dangerous. However, if you’re losing a substantial amount of weight or suspect you might have hyperemesis gravidarum (a severe form of morning sickness), it’s crucial to contact your healthcare provider immediately.

Pregnant woman sitting comfortably on a park bench looking at her smartphone, considering health information related to early pregnancy.

How Much Weight Should You Gain if Overweight or Obese?

If your pre-pregnancy weight was higher than recommended for your height, you’re not alone – a significant portion of pregnant women fall into the overweight or obese categories based on Body Mass Index (BMI).

• Overweight: Pre-pregnancy BMI between 25 and 29.9.
• Obese: Pre-pregnancy BMI of 30 or greater.

Recommended pregnancy weight gain varies based on your starting BMI:

• BMI 25 to 29.9: Aim to gain between 15 and 25 pounds total, averaging about 2 to 3 pounds per month during the second and third trimesters.
• BMI 30 or higher: The recommended gain is typically 11 to 20 pounds total.

While actively losing weight is unsafe, if you are overweight or obese, gaining less than the standard guidelines might be safe, but only under the close supervision and guidance of your healthcare provider. There has been some discussion among experts regarding the Institute of Medicine (IOM) guidelines for obese women, with some research suggesting that gaining slightly less (e.g., 6 to 14 pounds) might yield similar or even better outcomes for both mother and baby compared to gaining the recommended 15 to 20 pounds.

Always discuss your individual weight gain target with your provider. If you gain less than recommended, they will monitor you and your baby closely to ensure healthy progress.

Healthy Weight Management During Pregnancy (Instead of Dieting)

Pregnancy is unequivocally not the time for weight-loss diets, regardless of your starting weight. Restricting food intake can be harmful. Your focus should be on consuming enough calories and a wide range of nutrients. Avoid restrictive diets like keto or Atkins, as the carbohydrates they limit are essential for your baby’s development, and prolonged ketosis can be dangerous.

To manage weight gain healthily during pregnancy:

• Eat balanced meals and choose nutritious snacks.
• Stay well-hydrated, aiming for about ten 8-ounce glasses of water daily.
• Opt for complex carbohydrates (beans, fruits, vegetables, whole grains) over simple ones (white bread, pasta, rice).
• Monitor your weight gain pattern with your healthcare provider.

Weight Loss During Pregnancy: Warning Signs

While minor weight loss in early pregnancy can be normal, losing weight during the second or third trimester often signals a potential issue. Although sometimes it might be due to harmless fluctuations like losing water weight after temporary retention, it’s essential to inform your provider.

Your provider will assess your diet, activity level, and inquire about symptoms like nausea, heartburn, bloating, or constipation, which can affect appetite. They may also screen for conditions like depression or fetal growth restriction. Contact your provider immediately if you experience sudden, dramatic weight loss, such as losing five pounds or more within a week.

References

ACOG. 2021. Nutrition during pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/womens-health/faqs/nutrition-during-pregnancy

ACOG. 2021. Obesity and pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/womens-health/faqs/obesity-and-pregnancy

ACOG. 2020. Weight gain during pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2013/01/weight-gain-during-pregnancy

IOM. 2009. Weight gain during pregnancy: Reexamining the guidelines. The National Academies Press, Washington D.C. https://www.ncbi.nlm.nih.gov/books/NBK32813/

Kapadia MZ et al. 2015. Weight loss instead of weight gain within the guidelines in obese women during pregnancy: A systematic review and meta-analyses of maternal and infant outcomes. PLoS One 10(7): e0132650 https://pubmed.ncbi.nlm.nih.gov/26196130/

March of Dimes. 2020. Being overweight during pregnancy. https://www.marchofdimes.org/pregnancy/being-overweight-during-pregnancy.aspx

Rasmussen KM et al. 2010. Recommendations for weight gain during pregnancy in the context of the obesity epidemic. Obstetrics & Gynecology 116(5): 1191-1195. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4288953/

Robillard PY et al 2018. Relationship between pre-pregnancy maternal BMI and optimal weight gain in singleton pregnancies. Heliyon 4(5) E00615. https://www.cell.com/heliyon/fulltext/S2405-8440(18)30300-1

Siega-Riz AM et al. 2009. A systematic review of outcomes of maternal weight gain according to the Institute of Medicine recommendations: birthweight, fetal growth, and postpartum weight retention. American Journal of Obstetrics and Gynecology 201:339. E1-14. https://pubmed.ncbi.nlm.nih.gov/19788965/