Author: Rachel Tinius

Strength training is a beneficial component of a prenatal fitness program. It can help your body compensate for all the physical changes of pregnancy and provide the strength needed for baby lifting postpartum. The changes in your body weight and posture during pregnancy can create stress on joints, but strong muscles can help prevent the development of pain and injury.

If you’re new to strength training, start with a low weight or resistance band routine that focuses on major muscle groups.  You’ll be way ahead of the game by starting a strength training program during pregnancy, and better able to safely do all the lifting required once you have your baby.

Whether you’re new to strength training or have included it in your fitness program before your pregnancy, take a look at the tips listed below to help keep your routine safe and effective.  It’s essential to listen to your body and incorporate modification (such as a reduced weight/resistance, repetitions, and sets, or lift positioning) if exercises become uncomfortable. 

• Before starting any fitness routine, check with your healthcare provider to make sure exercise is safe during your pregnancy.
• You can continue your pre-pregnancy weight-training program once you become pregnant, but carefully monitor how you feel during and after training, and modify or eliminate exercises that cause pain or increased muscle soreness. 
• If you’re starting a strength-training program during pregnancy, begin with weight level or resistance that allows for one set of 10-12 repetitions without excessive strain. The weight amount and number of sets can be increased as the repetitions become easier. 
• Avoid maximal lifts. The force needed to perform maximal lifts makes this type of exercise unsafe during pregnancy. 
• Don’t hold your breath and bear down while doing your lifts. Always exhaling as you lift and inhale when returning to start position. 
• You can use strength training machines, free weights, resistance bands, or bodyweight in your routine. Use what’s readily available and within your budget.
• Modification of weight training exercises (such as dropping down in weight level and repetitions and sets, or adjusting positioning) may be needed as the pregnancy progresses.
• If a particular exercise causes pain or discomfort even after you’ve tried using modifications, it should be discontinued.  If pain persists, stop your strength training routine and consult with your healthcare provider.
• Avoid doing any strength training exercises while lying flat on your back (supine) after the first trimester. When you’re lying flat on your back, a large blood vessel that spans your abdomen can be compressed by the weight of your growing baby and can cause you to feel lightheaded and dizzy.  Modify supine positions by using a wedge or pillows to raise your upper body so you’re not flat on the floor.

© WKU {2022} All rights reserved.

Caloric intake should increase by approximately 300 kcal/day during pregnancy. This value is derived from an estimate of 80,000 kcal needed to support a full-term pregnancy and accounts not only for increased maternal and fetal metabolism but for fetal and placental growth. Dividing the gross energy cost by the mean pregnancy duration (250 days after the first month) yields the 300 kcal/day estimate for the entire pregnancy.^1,2 However, energy requirements are generally the same as non-pregnant women in the first trimester and then increase in the second trimester, estimated at 340 kcal and 452 kcal per day in the second and third trimesters, respectively. Furthermore, energy requirements vary significantly depending on a woman’s age, BMI, and activity level. Caloric intake should therefore be individualized based on these factors.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5104202

Macronutrients during pregnancy 

Concerning protein, the recommended dietary allowance is 71 grams per day, but realistically, 1.1 g/kg body weight is more accurate. Carbohydrates should comprise 45-64% of daily calories and this includes approximately 6-9 servings of whole grain daily. Total fat intake should comprise 20-35% of daily calories, similar to non-pregnant women.

Nutrition Postpartum when breastfeeding 

When breastfeeding your baby, kilocalorie needs are 500 kcals for the first six months and 400 kcals for the second six months (Academy of Nutrition and Dietetics, n.d.). This amount could be a little less or a little more depending on how much milk you are producing. For example, if you doing a combination of formula-feeding and breastfeeding your baby, you likely do not need the full 500 calories; Or, if you are breastfeeding your baby and also pumping additional milk, you may need more than 500 extra calories. Try to get the extra calories from high-quality food sources (See list below). 

It is also important to remember than when producing milk, your body may want you to keep a couple of extra pounds on you in order maintain milk supply. Do not worry about a few extra pounds! It is also not unusual for some women to lose weight when breastfeeding. Everyone is different. Don’t compare yourself to anyone else! Focus on keeping a healthy weight for you and your baby! 

List of important nutrients for breastfeeding, and where to find them. 

• Calcium: milk; cheese; yogurt; fish with edible bones; tofu processed with calcium sulfate; bok choy; broccoli; kale; collard, mustard, and turnip greens; breads made with milk.
• Zinc: meat, poultry, seafood, eggs, seeds, legumes, yogurt, whole grains (bioavailability from this source is variable).
• Magnesium: nuts, seeds, legumes, whole grains, green vegetables, scallops, and oysters (in general, this mineral is widely distributed in food rather than concentrated in a small number of foods).
• Vitamin B₆: bananas, poultry, meat, fish, potatoes, sweet potatoes, spinach, prunes, watermelon, some legumes, fortified cereals, and nuts.
• Thiamin: pork, fish, whole grains, organ meats, legumes, corn, peas, seeds, nuts, fortified cereal grain (widely distributed in foods).
• Folate: leafy vegetables, fruit, liver, green beans, fortified cereals, legumes, and whole-grain cereals.

https://www.ncbi.nlm.nih.gov/books/NBK235579

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5104202

Women who breastfeed require approximately 500 additional kcal/day beyond what is recommended for non-pregnant women.⁶⁸ The estimate is derived from the mean volume of breast milk produced per day (mean 780 mL, range 450-1200 mL) and the energy content of milk (67 kcal/100 mL).⁶⁹ During pregnancy, most women store an extra 2 to 5 kg (19,000 to 48,000 kcal) in tissue, mainly as fat, in physiologic preparation for lactation. If women do not consume the extra calories, then body stores are used to maintain lactation. It is not unusual for lactating women to lose 0.5-1.0 kg/month after the first postpartum month.⁷⁰

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5104202

Macronutrients during pregnancy 

There are even less evidence-based recommendations for nutrient intake during breastfeeding compared to pregnancy. Lactation is considered successful when the breast-fed infant is gaining an appropriate amount of weight. The recommended daily allowance for protein during lactation is an additional 25 g/day. 

Maternal factors such as stress, anxiety, and smoking can decrease milk production, but the quantitative and caloric value of breast milk does not change with dieting and exercise.^76–83 Moreover, a woman’s weight, BMI, body fat percentage, and weight gain during pregnancy do not influence milk production.^84–86

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5104202

Reviewed and edited by Heather Emerson-Payne, RD, PhD, 2023.

References

Academy of Nutrition and Dietetics. Nutrition Care Manual. Comparative Standards, Breastfeeding/Lactation. https://www-nutritioncaremanual-org.wku.idm.oclc.org/topic.cfm?ncm_category_id=1&lv1=272980&lv2=144973&lv3=269509&ncm_toc_id=269509&ncm_heading=Normal%20Nutrition. Accessed July 12, 2023.

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