While we often hear more about the health risks involved in being overweight, being underweight also carries with it a great number of health risks. In terms of pregnancy, there are several risks involved with being underweight. Among other things, the woman who is underweight and becomes pregnant is at a higher risk for having a miscarriage.
A recent study suggested that women who are underweight before they conceive will be around 70% more likely to have a first-trimester miscarriage. This increased risk of miscarriage seems to be due to a significant deficiency in folate and iron. Women who were underweight before they conceived were able to reduce their risk of miscarriage in the first trimester simply by taking prenatal vitamins that contain folate and iron, and by eating several servings of fresh fruits and vegetables each day.
There are other risks involved with being pregnant and underweight, as well. Among the biggest risk is that, because the mother doesn’t get enough nutrients, the baby will not either. Not getting enough folic acid, for example, will put your baby at an increased risk of being born with spina bifida or another neural tube defect. It is recommended that a pregnant woman get between 600 and 800 mcg of folic acid each day.
It is also important that a woman who is underweight when she becomes pregnant to gain enough weight during pregnancy. If you do not gain a sufficient amount of weight during pregnancy, you run the risk of your baby being born prematurely. Even if you do not have a miscarriage or if your baby is not born prematurely, you run the risk of your baby being born with a condition known as "small-for-gestational-age", which means that your baby was probably malnourished while he was developing in your womb. This creates a risk of several other problems that can occur later on in life.
Researchers suggest that women who are underweight before pregnancy should gain somewhere between 30 and 40 pounds during pregnancy. In contrast, a woman who is of an average weight should gain between 25 and 35 pounds, while an overweight woman should gain between 20 and 30 pounds.
If you are underweight when becoming pregnant due to an eating disorder, which could include bulimia or anorexia, you are putting your baby at risk. You should contact your health care provider immediately. Your health care provider may be able to provide you with assistance with or a referral for someone who can help you get on track nutritionally, to help you avoid miscarriage or birth defects, and to help make sure that your pregnancy is a healthy and successful time for both you and your baby.