Diet and Exercise in Pregnancy

A healthy diet and continued exercise are important in pregnancy. The advice below applies to low-risk women- if you have underlying health issues or pregnancy risk factors, please speak to your doctor.

Diet 

There is no need to make changes to your diet if you have a healthy and varied diet  except to:  limit the intake of certain types of fish with a high Mercury content, avoid foods that may cause Listeria (like pre-prepared foods and salads, cold meats and soft cheeses) and avoid undercooked meat that can cause toxoplasmosis.

Further information can be obtained here:  Food and Nutrition in Pregnancy, The Royal Women’s Hospital, Melbourne

Supplements

All women should take Folic acid (0.5mg/day) and Iodine (150mcg/day) supplements for at least three months before pregnancy. Folic acid should be continued till 12 weeks of pregnancy and Iodine throughout pregnancy and whilst breastfeeding. 

Other supplements that are often prescribed are iron (for  iron deficiency - more common in vegans and vegetarians), Vitamin D (for known to be deficiency) and Vitamin B12 (for known deficiency and for Vegans).

Pregnancy multivitamins could make morning sickness worse.

We discourage the use of probiotics as it may increase the risk  of developing pre-eclampsia.

Weight gain in pregnancy

Recommended weight gain depends on pre-pregnancy body mass index (BMI). BMI is calculated by dividing weight (in kilogram) by height (in metres) squared. Tables with BMI calculations are readily available.

Pre-pregnancy BMI and Recommended weight gain during 2nd and 3rd trimester of pregnancy:

• Underweight: BMI Less than 18.5 - Weight gain 12.5 to 18kg
• Normal weight: BMI 18.5–24 (European) 18.5 to 22.9 or (Asian) - Weight gain 11.5 to 16.0kg
• Overweight: BMI 25- 29(European) or 23 - 27.5 (Asian) - Weight gain 7 to 11.5kg
• Obese: BMI Above 30(European) or Above 27.5 (Asian) - Weight gain 5 to 9kg

Dieting is not usually recommended in pregnancy, instead limit the intake of high fat and high carbohydrate foods and do daily exercise such as walking.

Healthy weight gain in pregnancy, The Royal Women’s Hospital, Melbourne

Exercise in pregnancy

Women with an uncomplicated pregnancies should do regular aerobic and strength conditioning exercise. If you are not regular exerciser, start slow and increase the frequency and duration of exercise over weeks. Regular exercise may prevent excessive weight gain, reduce pregnancy symptoms and the risk of depression. It may prevent diseases such as gestational diabetes and pre-eclampsia. Exercise in pregnancy may also cause a shorter and less complicated labour and fewer complications in new born babies although the evidence is not conclusive.

There is no evidence to suggest that regular exercise during pregnancy is detrimental to a woman or her fetus. 

Pelvic floor exercises during and after pregnancy is also important to reduce the risk of urinary incontinence.

The following tips could be helpful:

• How often? Be physically active on most days of the week.
  
• How much? 150 to 300 minutes of moderate-intensity physical activity each week. Ideally, do at least 30 min of exercise on most days of the week.
• At what intensity? It depends on the baseline level of fitness and previous exercise routine. If previously inactive, aim for moderate intensity exercise. Continue with moderate-intensity exercise. If used to high-intensity exercise, continue with it but adjust your routine based on changes in comfort and tolerance. Special attention should also be paid to ensure adequate nutrition, hydration and avoidance of overheating.
• What is moderate intensity exercise? During 'moderate exercise' you can comfortably hold a conversation during exercise. During ‘vigorous exercise’ you need to pause for breath during exercise. If you prefer to monitor your heart rate aim for a zone of 60- 80% of your maximal aerobic capacity is recommended for normal-weight pregnant women. (see below)
• What type of exercise? Ideally both aerobic and strengthening exercises.
• Walking at a brisk pace is a practical mode of aerobic exercise during pregnancy. Other options include stationary cycling and swimming. Swimming and other water-based activities may reduce leg swelling. Water-based aerobics lasting 45 min in water temperatures up to 33.4 degrees Celsius is unlikely to raise maternal core temperature above 38 degrees Celsius (39 degrees Celsius considered the teratogenic threshold). Immersion in heated spas and hydrotherapy pools should be limited in duration. Women who were running prior to pregnancy may continue to do so.
• Two sessions of strengthening exercises per week on non-consecutive days is ideal. Women without prior experience of resistance training can aim to perform 1 – 2 sets of 12 – 15 repetitions for each exercise. Avoid heavy weight-lifting and activities that involve straining, holding breath, or that are isometric (like planking). Exercises should not be performed lying flat on the back after the first trimester and walking lunges are best avoided to prevent injury to pelvic connective tissue.

Warning signs to stop  exercise and seek medical attention include:

• chest pain
• unexplained shortness of breath
• dizziness
• feeling faint or headache
• muscle weakness
• calf pain, swelling or redness
• sudden swelling of the ankles, hands or face
• vaginal bleeding or amniotic fluid loss
• decreased fetal movement
• uterine contractions or pain in the lower back, pelvic area or abdomen (potentially indicating pre-term labour)

Target heart rate during excercise zones for normal-weight pregnant women: