1. Chapter 14 NUTRITION DURING PREGNANCY AND LACTATION

2. Physiology of Pregnancy
Fallopian tubes: narrow ducts leading from the ovaries to the uterus
Amniotic sac: a membrane that surrounds the fetus containing the amniotic fluid
Placenta: an organ produced during pregnancy from maternal and embryonic tissues. The placenta secretes hormones, transfers oxygen and nutrients from maternal to fetal blood and removes wastes.
Gestation: the time between conception and birth, approximately 40 weeks in humans
Preterm or premature: an infant born before 37 weeks of gestation
Very low birth weight: a birth weight of less than 3.3 lbs (1.5 kg)
Small-for-gestational-age: a birth weight of less than 5.5 lbs
(2.5 kg)
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3. Recommendations for Weight Gain during Pregnancy
Source: From Committee to Reexamine IOM Pregnancy Weight Guidelines, Institute of Medicine, National Research Council.
Weight Gain During Pregnancy: Reexamining the Guidelines. Washington, DC: National Academies Press, 2009.These
guidelines have been adopted by Health Canada: Canadian Gestational Weight Gain recommendations: Available online at
Accessed Nov 19, 2010.
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4. Distribution of Weight during Pregnancy
Figure 14.4 Sources of weight gain in pregnancy
Weight gained during pregnancy is due to increases in the weight of the mother’s tissues, as well as the weight of the fetus, placenta, and amniotic fluid.
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5. Pattern of Weight Gain during Pregnancy
Figure 14.5 Recommended weight gain during pregnancy
The same pattern of weight gain is recommended for women who are normal weight, underweight, overweight, or obese at the start of pregnancy, but total weight gain recommendations differ.
Source: Adapted from Committee to Reexamine IOM Pregnancy Weight Guidelines, Institute of Medicine, National Research Council. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington, DC: National Academies Press, 2009.
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6. Maternal Weight Gain and Birth Weight
Figure 14.6 Relationship between maternal weight gain and birth weight
Gaining more or less than the recommended amount of weight during pregnancy increases the incidence of large-for-gestational-age and low-birth-weight babies, respectively.
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7. Weight Gain of Canadian Women during Pregnancy
Figure 14.7 Weight gain of Canadian women during pregnancy.
Some Canadian women gain less than, within or more than the recommended weight during pregnancy, but it varies depending on the woman’s pre-pregnancy BMI. The higher the mother’s pre-pregnancy BMI, the more likely her weight gain during pregnancy will exceed recommendations.
Source: Lowell, H. and Miller, D. C. Weight gain during pregnancy: Adherence to Health Canada’s guidelines. Health Reports 21(2), 1-5, Available online at Accessed November 19, 2010.
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Maternal Weight Gain
In 2006, the Public Health Agency of Canada undertook a survey of the experiences of women during and immediately after pregnancy, which included information on weight gain during pregnancy.
Results revealed that a woman’s pre-pregnancy weight is a good predictor of her weight gain during pregnancy. Women with BMIs greater than 27 gained the most weight during pregnancy, with 55% of women in this category gaining more weight than is recommended. Less weight was observed in women with normal or low body weights.
Higher than recommended weight gain was more common among women having their first baby, women who are less educated and women within the Aboriginal population.
Women who gained more weight during pregnancy were also more likely to retain that extra weight after delivery.
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9. Physical Activity during Pregnancy
Guidelines for exercise during pregnancy were put together by the Society of Obstetricians and Gynaecologists of Canada.
Researchers also developed the Physical Activity Readiness Medical Examination form, which is available to physicians.
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10. Physical Activity during Pregnancy (continued)
Guidelines for exercise during pregnancy were put together by the Society of Obstetricians and Gynaecologists of Canada.
Researchers also developed the Physical Activity Readiness Medical Examination form which is available to physicians.
Source: Davies, G. L. A., Wolfe, L. A., Mottola, M. F. et al. Joint SOGC/CSEP Clinical Practice Guideline: Exercise in pregnancy and
the postpartum period. Can. J. Appl. Physiol. 28(3): , 2003.
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11. Physical Activity during Pregnancy (continued)
Source: PARmed-X for Pregnancy: available online at from Canadian Society for Exercise Physiology: Accessed August 22, 2011.
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12. Discomforts of Pregnancy
Physiological changes during pregnancy can cause uncomfortable side effects for the mother. These can include:
Edema
Morning sickness
Heartburn
Constipation and hemorrhoids
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13. Complications of Pregnancy
Pregnancy can cause complications for the mother and the child. These can include:
Pregnancy-induced hypertension, which includes gestational hypertension, preeclampsia and eclampsia
Gestational diabetes mellitus
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14. Nutritional Needs during Pregnancy
Figure Energy and nutrient needs during pregnancy and lactation
This graph illustrates the percentage increase in recommended nutrient intakes for a 25-year-old woman during the third trimester of pregnancy and during lactation. *The RDA for iron during lactation is equal to half the RDA for nonpregnant, nonlactating women.
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Nutritional Needs during Pregnancy
Figure Using Canada’s Food Guide during pregnancy
Canada’s Food Guide’s general recommendations, when combined with the special advice given to women of child-bearing age, can be effectively
used for meal planning during pregnancy.
Source: Health Canada: Canada’s Food Guide: Get Your Copy. Available online at Accessed December 12, 2010.
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16. Nutritional Needs during Pregnancy
There is a relationship between lack of folic acid and neural tube defects.
In the early 1990s, Health Canada and other organizations advised women who could become pregnant to obtain folic acid intake from supplementation or from a diet of at least 400 micrograms daily to prevent neural tube defects.
American studies revealed only 1/3 of women were meeting the requirement. Folate fortification of white flour, cornmeal and pasta became mandatory in Canada.
The success of this program can be seen in the decline of neural tube defects by 46%.
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17. Nutritional Needs during Pregnancy (continued)
Energy and nutrient needs during pregnancy can be met by following the recommendations of Canada’s Food Guide.
Additional grains, vegetables and fruits provide energy, protein, folate, vitamin C and fibre, particularly if whole grains are chosen.
An extra serving of milk provides energy, protein, calcium, vitamin D and riboflavin.
Additional lean meat provides energy, protein, vitamins B6 and B12, iron and zinc.
Supplements are recommended even when Canada’s Food Guide is followed:
Folic acid before and during the pregnancy
Iron during the second and third trimesters
Multivitamin and mineral supplement for those with limited food choices
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18. What is in a Prenatal Supplement?
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19. Factors that Increase Pregnancy Risk
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20. Factors that Increase Pregnancy Risk (continued)
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Pregnant Teens
The rate of teen pregnancies in Canada has declined.
Teen pregnancies accounted for 6.8% of all births in 1995 and 4.8% in 2004.
Teen pregnancy remains a public health problem. The mother herself is still growing, is at higher risk for developing hypertensive disorders, and is more likely to deliver preterm and deliver a low birth weight baby.
To produce a healthy baby, a pregnant adolescent needs early medical intervention and nutritional counselling.
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22. Micronutrient Needs of Pregnant Teens
Figure Nutrient needs of pregnant girls (14 to 18 years old)
The percentage increase in micronutrient needs above nonpregnant levels is shown here for a 14- to 18-year-old girls during pregnancy.
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Fetal Development
Figure Critical periods of development
The critical periods of development are different for various body systems. Heart defects are the most common birth defect.
Source: Adapted from Moore, K., and Persaud, T. The Developing Human, 5th ed. Philadelphia: W. B. Saunders Company, 1993.
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24. Mother’s Exposure to Toxins and Fetal Development
Pregnant women need to be aware of potential toxins in their food, water and environment.
Health Canada reports that most fish in Canada have very low mercury levels. The exceptions are fresh or frozen tuna, shark, marlin, orange roughy and escolar.
Women who are planning to get pregnant or pregnant are advised to limit their fish intake to the amounts posted on the Health Canada website.
Light tuna has low levels of mercury and is of little concern. Health Canada does recommend limits on albacore tuna to 4 servings/week for women who are planning on getting pregnant, pregnant or breastfeeding.
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25. Mother’s Alcohol Intake and Fetal Development
In Canada, Public Health is very clear:
“There is no safe amount or safe time to drink alcohol during pregnancy.”
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26. Smoking during Pregnancy
The Public Health Agency of Canada recommends that all women stop smoking during pregnancy and maintain a smoke-free environment during and after pregnancy.
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27. Reaching Canadian Mothers at Risk
The Canadian Prenatal Nutrition Program (CPNP) was launched in 1995 to support and improve maternal health and nutrition during pregnancy, to reduce unhealthy birth weights and to encourage breastfeeding.
Between 1998 and 2003, 7% of all pregnant Canadian women accessed CNCP. These women included 60% of low-income women and 40% of pregnant teens.
The CPNP is a series of individual projects designed and implemented in communities throughout Canada to meet locally identified needs.
At the present time there are more than 300 CNCP sites servicing more that 50,000 pregnant women in 2000 communities across Canada.
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28. Reaching Canadian Mothers at Risk (continued)
Source: Public Health Agency of Canada. The Canada Prenatal Nutrition Program: A decade of promoting the health of mothers, babies, and communities, Available online at Accessed Dec 18, 2010.
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29. Reaching Canadian Mothers at Risk (continued)
Exmaples of projects include:
Buns in the Oven (Ottawa)
Health Moms, Healthy Babies (Yukon)
Prenatal Tobacco Cessation Pilot Project (Alberta)
Figure Services offered to pregnant women at CPNP projects
Source: With permission from Public Health Agency of Canada. The Canada Prenatal Nutrition Program: A decade of promoting the health of mothers, babies, and communities, Available online at Accessed December 18, 2010.
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30. Physiology of Lactation
Lactation involves the synthesis of milk components, including protein, lactose and lipids, and the movement of the milk through the milk ducts to the nipple.
Colostrum is immature milk, secreted during the first days after delivery. Colostrum is rich in protein and immune factors.
The release of milk from the glands through the ducts is referred to as let-down.
The let-down of milk is triggered by the hormone oxytocin.
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31. Physiology of Lactation
Figure Hormones of lactation
When the infant suckles, nerve receptors in the nipple send signals to the hypothalamus, which signals the release of prolactin and oxytocin.
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32. Maternal Nutrient Needs during Lactation
The need for nutrients is even greater during lactation than during pregnancy.
Human milk contains about 160 kcalories per cup (250 ml).
The EER for lactation is estimated by adding the TEE of nonlactating women and the energy in the milk and then subtracting the energy supplied by maternal fat sources.
Lactating women require approximately an additional liter of fluid a day.
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33. Nutritional Needs of Infants
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Vitamin D and Infants
The Canadian Pediatric Society recommends that all infants receive 10 micrograms/day of Vitamin D during the first year, with an increase to 20 micrograms/day between October and April north of the 55th parallel to compensate for lack of sunshine during the winter months.
Breast milk contains little vitamin D, so breast fed babies will require a supplement.
Vitamin D is added to formula to meet the needs of formula-fed babies.
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35. Nutritional Needs of Infants
Figure Kcalorie distribution in infant versus adult diets
A comparison of the proportions of kcalories from carbohydrate, fat, and protein in human milk with the proportions recommended for an adult illustrates how much more fat infants need.
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36. Assessing Infant Growth
Figure WHO Growth Charts are used to monitor infant growth
Source: c Dietitians of Canada. All rights reserved. Permission to print in its entirety. For noncommercial use only. WHO Growth Charts adapted for Canada. Available online at Accessed December 18, 2010.
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37. Comparing Breast Milk and Formula
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38. Breastfeeding in Canada
Health Canada recommends that all babies be fed only breast milk during the first 6 months of life. Infant formula and solid foods should not be introduced until after the age of 6 months.
In 2010 a study looked at the prevalence of exclusive 6-month breastfeeding among Canadian women and determined which maternal characteristics best predicted this practice:
Women who have partners
Women who do not smoke during pregnancy
Women who deliver in their home
Women who do not work
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39. Breastfeeding in Canada (continued)
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40. Breast Pumps Can Be Used for Bottle Feedings
Figure Breast pumps can be used to pump milk for bottlefeedings, relieving a mother of responsibility for all feedings.
(c istockphoto.com/Joakim Leroy)
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41. Position of Bottle is Important
Figure Proper feeding position during bottle-feeding allows the formula to be swallowed easily and prevents air from being swallowed. (istockphoto.com/Paul Kline)
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Baby Formula
Baby formula composition is described within the Canadian Food and Drug Regulations. These regulations are enforced by the Canadian Food Inspection Agency.
The regulations specify the minimum amounts of carbohydrate, fat, protein, vitamins and minerals and set limits on the amount of additives or ingredients in baby formula.
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43. Safe Baby Bottle in Canada
In 2008, Canada became the first country to ban infant bottles containing bisphenol A. This is precautionary for a vulnerable population as Health Canada concludes that exposures to bisphenol A from plastic materials is unlikely to harm human health.
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