Healthy PKU Pregnancy

How strict must my diet be to have a healthy pregnancy?

Women with PKU should keep their blood phenylalanine levels between 2-6 mg/dL. In other words, the diet must be extremely strict. The amount of phenylalanine and special formula needed varies from woman to woman, and nutritional counseling is very important if pregnancy is considered. In addition, the pregnant woman with PKU must make sure she is gaining the proper amount of weight during pregnancy.

How can a pregnant woman with PKU gain the proper amount of weight that she needs?

A pregnant woman with PKU must eat for two, gaining weight like any other pregnant mother to be. To gain the proper amount of weight during pregnancy, she must eat foods high in calories while low in protein. Because of the diet limitations, weight gain is often promoted with sugars and fats. Special low protein products, such as cookies, pizzas, and baked goods can also provide extra calories.

What are some difficulties a pregnant woman with maternal PKU may encounter?

The strict PKU diet and the daily intake of formula may interrupt daily activities and can be frustrating on an everyday basis.
It may be hard to follow the diet and take the formula in social situations and particularly in restaurants.
Nausea and/or vomiting (which are common in early pregnancy) may make it difficult to consume all the special formula.
PKU mothers should also resist cravings for high phenylalanine foods (peanut butter, ice cream, meat, etc.)

Yes, it can be frustrating. But, pregnancy is also a wonderful experience and these challenges are small compared to the risks that not following the diet may cause to your unborn child.

Read advice and ideas to cope with these challenges in these two sections of this Toolkit:

Also, discuss issues that arise with the PKU medical staff (nutrionist, nurse, etc) at your ob/gyn clinic or doctor's office.

Don't let the stress and responsibility for maintaining low phe levels take away the joy of bringing a new life in the world. Maintaining a strict diet and taking formula is necessary for your child’s health. But you can manage it with planning, determination and support.

Our complete Maternal PKU & Pregnancy Guide is now online!

If you are a woman with phenylketonuria (PKU), and are planning to get pregnant, or already are pregnant, we created this guide for you! Developed by metabolic and nutrition specialists at Children’s Hospital Boston, the guide includes sections on PKU, Maternal PKU, genetics, newborn health, PKU recipes, and PKU & pregnancy resources. Being pregnant with PKU is challenging, but with careful planning ahead of time, and with the right diet, health care, and information, you can experience the wonder and joy of carrying and delivering a healthy baby.

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