It has been well established that body mass index (BMI), or the percentage of body fat one carries, is related to fertility in women. A BMI of between 20% and 25% is recommended for women who are planning to conceive, the average BMI in women today is 28%. A BMI of 30% or above is considered obese.
Women with a BMI lower than 20% may have irregular menstrual cycles lessening the likelihood of conception. Women who do conceive with a BMI lower than 20% run the risk of having a low birth weight baby as well as an increased risk of complications and infant death. There is an increased risk of degenerative diseases in children born to women with a BMI lower than 20%.
Women with a BMI higher than 25% also have a lower likelihood of conception, especially in women who have abdominal fat. Abdominal fat may indicate insulin resistance which also affects the levels of hormones in the body that supports the generation of a viable egg during ovulation. Women who do conceive with a BMI higher than 25% are at a greater risk for gestational diabetes and pre-eclampsia as well as emergency caesarean delivery. Pre-term infants born to women with a BMI higher than 25% have a higher mortality rate.
Experts suggest that women who are planning a pregnancy take steps before pregnancy to reach a healthy weight with a BMI between 20% and 25%. One study followed a group of overweight women who were experiencing infertility for six months. The women had agreed to participate in a weekly diet and lifestyle change program. Most of the women who completed the program lost an average of 20 pounds, regained regular ovulation, conceived and experienced successful pregnancies.
Nutritional Status and Pregnancy
Women, who are planning a pregnancy, should be aware that their level of nutritional health at the time of conception affects the development and growth of the embryo. The first few weeks of pregnancy is crucial and relies greatly on the nutritional status of the mother, even before the pregnancy is discovered. Therefore women who are planning a pregnancy should take steps before conception to gain a level of nutritional health and balance.
Women who are planning a pregnancy should have a healthy diet that includes a wide variety of vegetables, fruits, lean meats and water as well as complex carbohydrates and whole grains. Folic acid and essential fatty acids such as EPA and DHA are extremely important in development of the fetus. Women who are planning a pregnancy should take adequate amounts of nutritional supplements which contain folate, EPA and DHA. Other nutrients that are recommended for women who are planning a pregnancy are: thiamin, riboflavin, Vitamin A, Vitamin C and Vitamin D.
If you are planning a pregnancy speak to your physician about your diet and nutrition supplements.
Williamson, C. S. (2008) Nutrition in pregnancy. Nutrition Bulletin, 31, 28-59.