Nutritional Intake
Many nutrients are needed to form the placenta, to increase the size of the uterus and breast tissue, and to create amniotic fluid. A mother's blood volume increases by 25–50%, and more fluids, iron, B vitamins, folic acid, zinc and copper, calcium, magnesium, and proteins are needed to support this new blood. Storage levels of most nutrients must be obtained from the diet as well. A nutritional consult may be helpful both during and after pregnancy to ensure she sufficiently rebuilds her nutrient stores, especially while breastfeeding and before becoming pregnant again.
A dietary consult can sometimes be helpful, especially for tips on creative inclusion of nutritional foods or increasing calories with nutrient dense foods (e.g. peanut butter).
Nutritional Assessment
For most women with HG, intake of adequate food and fluids is practically impossible for weeks or even months. Standardized nutritional assessment tools are not scaled for pregnant women, yet many women with HG would still show severe risk of malnutrition. However, less than 20% of women get nutritional support.
Food Aversions and Cravings
It is very typical for those with HG to have very strong aversions and cravings that prohibit a well-balanced diet for much of their pregnancies, and these preferences may change frequently until delivery. It may be the smell, texture, appearance or taste that leads to nausea and vomiting.
It is common to find aversions to protein foods and vegetables for much of the first trimester, if not longer. Even when women can eat, it might be less than healthy foods with little variety. This can cause guilt and frustration, as well as significant nutritional deficiencies. Women should be reassured and encouraged to make the best decisions possible but focus on increasing fluid and calorie intake any way possible.
Common Triggers
The cause is likely a complex interaction of endocrine (hormone) changes related to pregnancy, nutrient deficiencies, mechanical changes in the body, gastrointestinal dysfunction (e.g. reflux), and changes in neurochemicals. The intensity of cravings and aversions can be very high and trigger repeated bouts of severe nausea and/or vomiting.
Thinking about foods, smelling them, or even just seeing food on the television is enough to trigger vomiting for many. She may crave very specific combinations of food characteristics, such as salty and crunchy, or sweet and soft.
Entering a grocery store, opening the refrigerator, or even contemplating food preparation are usually intolerable for at least the first trimester. There is very strong evidence this is caused by certain genes. This has a significant impact both on her and her family and is not something she can control. Finding foods that meet these criteria are crucial to prevent malnutrition.
Support and Understanding
These issues must be acknowledged, supported, and accepted by her family and care providers. It's impossible to fully understand the unusual dietary preferences of HG unless you have experienced it for yourself. Trying to force other foods that are aversive will typically result in vomiting and greater anxiety for the mother.
With HG, any calorie is a good calorie. Any food a mother can tolerate should be offered as soon as possible.
Monitor for Refeeding Syndrome
Women with poor nutritional intake for more than 10 days, weight loss exceeding 15% of preconception weight, electrolyte loss, and low serum magnesium levels are at high risk for refeeding syndrome. Methodical and gradual initiation of nutritional support, starting at 25% of needed nutrition and slowly increasing to goal as tolerated at a controlled rate, is imperative to prevent severe electrolyte and fluid shifts that can be life-threatening.
Daily monitoring of laboratory results, such as phosphorus, magnesium, sodium, calcium, glucose, and potassium, are important over the first week of refeeding. Close monitoring should be continued for at least 10 days, or until electrolytes are stable.
Nutritional Deficiencies and Hyperemesis
Women with HG may vomit or have severe nausea for months that will leave her exhausted and very depleted. It is imperative that women losing weight rapidly and not responding to medications be given nutritional support to prevent significant nutrient depletion in these women. Vitamins, especially B vitamins, are depleted very quickly and if not replaced can worsen her symptoms or put her at risk for life-threatening neurological disorders like Wernicke's Encephalopathy.
Deficiencies left uncorrected may have numerous adverse effects on the breastfeeding child, such as bleeding and neurodevelopmental disorders, especially if a mother had prolonged HG.
