The main recommendation for pregnancy is to initiate it with a weight within a healthy range (body mass index from 18.5 to 25 kg/m2). Body mass index (BMI) is the association between weight and height, determined by the following formula: weight (in kilograms) / height x height (in meters). There are also online BMI calculators, as that from the Mexican Institute of Social Security [link http://www.imss.gob.mx/salud-en-linea/calculaimc].
It is more difficult for women to get pregnant when their BMI is outside the healthy range, as they even stop having regular menstrual cycles, and thus their fertility decreases. Women who begin pregnancy with a BMI below 18.5 kg/m2 have a higher risk of preterm birth or that their baby is born with a low weight. On the other side, beginning a pregnancy being overweight (BMI 25 to 30 kg/m2) or obese (BMI over 30 kg/m2) is associated with:
- Six times the risk of suffering from gestational diabetes or preeclampsia during pregnancy
- Greater risk of preterm birth, cesarean section (C-section) and further complications for both the mother and the baby during delivery
- Greater risk for the newborn to have a higher weight than recommended (over 4 kg)
- Higher risk of children having overweight, obesity, hypertension, cardiovascular disease, diabetes and depression on late stages of life.
- Increases the risk of the mother of developing type 2 diabetes, cardiovascular disease, cancer and depression after birth.
Considering that 75.6% of Mexican women over 20 years of age are either overweight or obese (37% and 38.6% respectively), it is important to promote weight maintenance before getting pregnant. This will allow preventing further complications on them and their offspring, as well as a decreased future risk of chronic diseases.
It is also crucial to control weight gain during pregnancy. If too much weight is gained, it is more complicated to return to the previous one, besides the health risks that it implies. It is based on pre-pregnancy weight (pregestational, before pregnancy) that the weight to increase during pregnancy is determined. Recommended monthly weight gain during the first trimester, and weekly on the second and third can be observed in the following table, as well as total weight gain, according to the BMI before pregnancy:
Calorie and certain nutrient requirements increase during pregnancy, but not as much as ‘eating for two’ as it is commonly thought. During the first trimester, it is not advised to increase calorie consumption. From the second semester on, it is recommended to increase 340 calories per day, and 450 calories beginning the third. There should be support from a dietitian and a gynecologist to adjust the eating plan according to their needs. Here we present some examples of meals with the recommended calories for both stages:
It is recommended that women in reproductive age with an active sexual life take folic acid, as this nutrient is essential during the first weeks of pregnancy for baby’s development. During pregnancy, iron requirement also increases, which can be met with a supplement and an adequate consumption of animal-origin food, legumes (regular, fava or white beans, lentils) and green leafy vegetables. Besides, an adequate consumption of vitamin D and calcium must be secured through greater dairy or fortified food consumption.
Pregnant women must not drink alcohol nor smoke, as the baby’s neurological development might be affected. Besides, caffeine consumption must be reduced. In relation to physical activity, 30 minutes of low intensity are recommended daily, such as walking.
It is advised to seek support from the healthcare team to achieve a healthy weight before pregnancy, as well as to meet the recommended weight gain during this stage. A proper diet provides all nutrients needed for baby’s development and prevents chronic diseases in both the mother and the baby.
National Academy of Medicine (Mexico). Guías alimentarias y de actividad física en contexto del sobrepeso y obesidad en la población mexicana. Available from: https://www.anmm.org.mx/publicaciones/CAnivANM150/L29_ANM_Guias_alimentarias.pdf
Academy of Nutrition and Dietetics. Position of the Academy of Nutrition and Dietetics: Obesity, reproduction and pregnancy outcomes. Journal of the Academy of Nutrition and Dietetics: 2016; 116(4). Available from: https://www.eatrightpro.org/-/media/eatrightpro- files/practice/position-and-practice-papers/position- papers/obesityrepropreg.pdf?la=en&hash=18D6D3E5218C479CBD804CAE461145501ACF56B3
Academy of Nutrition and Dietetics. Position of the Academy of Nutrition and Dietetics: Institute of Medicine & National Research Council of the National Academies. Implementing guidelines on weight gain and pregnancy. 2013. Available from https://www.eatrightpro.org/- /media/eatrightpro-files/practice/position-and-practice-papers/position- papers/position_healthy_pregnancy.pdf?la=en&hash=8E776E3A2DF554EC8E287CF04E75617B61F FB88D
Ministry of Health (Mexico). Norma Oficial Mexicana NOM-043-SSA2-2012. Servicios básicos de salud: Promoción y educación para la salud en materia alimentaria. Criterios para brindar orientación. 2013. Available from: http://www.dof.gob.mx/nota_detalle.php?codigo=5285372&fecha=22/01/2013