Chapter 14 NUTRITION DURING PREGNANCY AND LACTATION.

Chapter 14NUTRITION DURING PREGNANCY AND LACTATION

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)

Copyright 2012, John Wiley & Sons Canada, Ltd.

Recommendations for Weight Gain during Pregnancy


Distribution of Weight during Pregnancy


Pattern of Weight Gain during Pregnancy


Maternal Weight Gain and Birth Weight


Weight Gain of Canadian Women during Pregnancy


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.


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.


Physical Activity during Pregnancy (continued)


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


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


Nutritional Needs during Pregnancy


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%.


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


What is in a Prenatal Supplement?


Factors that Increase Pregnancy Risk


Factors that Increase Pregnancy Risk (continued)


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.


Micronutrient Needs of Pregnant Teens


Fetal Development


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.


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.”


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.


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.


Reaching Canadian Mothers at Risk (continued)


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.


Physiology of Lactation


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.


Nutritional Needs of Infants


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.


Nutritional Needs of Infants


Assessing Infant Growth


Comparing Breast Milk and Formula


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


Breastfeeding in Canada (continued)


Breast Pumps Can Be Used for Bottle Feedings


Position of Bottle is Important


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.


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.


Copyright

Copyright © 2012 John Wiley & Sons Canada, Ltd.

All rights reserved. Reproduction or translation of this work beyond that permitted by Access Copyright (The Canadian Copyright Licensing Agency) is unlawful. Requests for further information should be addressed to the Permissions Department, John Wiley & Sons Canada, Ltd. The purchaser may make back-up copies for his or her own use only and not for distribution or resale. The author and the publisher assume no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information contained herein.

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Chapter 14 NUTRITION DURING PREGNANCY AND LACTATION.

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