If you miss a day of prenatal vitamins while pregnant, it's important to note that the effects may be minimal. However, if you are unintentionally missing doses on a regular basis then your baby may not be receiving all the essential vitamins and minerals they need for proper development. It is best to try and stick with a consistent routine when taking prenatal vitamins as this will ensure that your baby is getting all the nutrients they need throughout their development in utero. If you do happen to forget or miss a dose, it is recommended to take them as soon as possible so that your baby can get back on track with their nutrient intake.