Stress is an emotional process that is activated when the person face a situation that demands the selection and implementation of various resources, necessary to address it. The changes that can trigger the stress process are environmental or internal (physiological changes and cognitive variables). If we consider that a pregnancy implies a revolution of internal changes and also of the environment, there is no doubt in affirming that the experience of being pregnant is in itself stressful. However, like many things in life, here again the glass is half full or half empty depending on the eyes that look at it. The assessment that the woman makes of her own state, the development that the gestation itself is having, the expectations it has on how pregnancy and childbirth will develop, the assessment that it makes on its ability to cope to be a mother, or the support she has during these nine months will be crucial factors for the woman to live her pregnancy as a highly stressful and distressing situation or, on the contrary, as an experience of full placidity and well-being. Impact of stress on pregnancy Although many women fear of it, stress, when it is acute (or punctual) or mild, does not influence pregnancy. It is important to know this fact, since there are pregnant women who are stressed or scared to be nervous because they fear the repercussions it may have on the development of their child. External factors of stress in pregnancy As for external factors, there are many changes that occur in the world of pregnant women in the coming months. The changes alone produce a certain amount of stress that, depending on how the woman values them, can make the situation a completely aversive experience or, conversely, a challenging experience. The problem of the pregnant woman is that, on many occasions, she lacks physical strength to cope with these changes. Your physiological condition may force you to have absences at work by having to go to medical check-ups. The work that you couldn’t do because of those absences will have to be done later, and how do you do it then if you are tired? The pregnant woman must, together with her partner, prepare the house and organize her agenda for the arrival of the new baby, at what time will she do it if she is tired? If stressful situations also occur around you, in which you have no choice but to get involved, for example the death of a loved one, domestic breakdowns, family or couple problems, etc., how can you fulfill your minimum eight hours of rest daily? Some studies maintain that the level of tiredness of a pregnant woman, when the physical and emotional causes of her new condition are united, resembles that of a runner who prepares a marathon. However, and although we find it a lie, many pregnant women do not perceive that they are stressed, since the assessment that they themselves make about their ability to cope with this situation is so positive that pregnancy causes them an enormous sense of well-being that they regret losing once they give birth. That is why a third group of factors, the cognitive variables, which have to do with the interpretation of the situation, the coping style, the belief in one's own abilities to cope with stress, are fundamental when determining if the pregnant woman will suffer or not.