Pregnancy

Your guide to pregnancy

Pregnancy is the period of gestation which, in all mammals, means the time when a fertilised egg develops into an embryo and, later, a foetus within the womb of the mother. In most cases, women can expect to give birth 40 weeks after their last menstrual period. That is around nine months depending on when in the calendar the woman in question became pregnant. In the main, human pregnancies are split into three distinct periods, known as trimesters. The first of these includes the conception and the formation of the foetus. During the second trimester, the body of the pregnant woman expands to accommodate the growing baby. The third trimester of pregnancy is usually when the baby's movements are first felt, and the abdomen transforms its shape in preparation for childbirth.

 Tender breasts are one of the first signs you may notice that you have become pregnant. More tiredness than usual is also a common symptom. Some women also notice that they feel slight bleeding or cramping, too. Because of the increase in blood flow around the body, headaches can also be a sign that you are pregnant. Famously, morning sickness - which means vomiting or nausea with little forward notice - is another early sign that you may be pregnant.

There are plenty of hormones that get released when you are pregnant. These flow through the body and some will end up in the brain. As such, there is a chemical change to the brain's usual state that will occur when pregnant. However, the degree to which hormones like oestrogen and progesterone affect the brain differs between individuals. Certainly, the brain is only exposed to more of the hormones it usually receives. There is nothing that is introduced into the brain as a result of being pregnant that you would not be exposed to at other times.

There are numerous home pregnancy tests that you can take, nearly all of which are reasonably reliable. Some involve testing the chemical make-up of your urine, and although their accuracy varies, most false results come about because they have not been used correctly. If you see a pregnancy test result that you doubt, then use another method to check it. If you want a truly accurate answer, then see your doctor.

Not all women crave certain foodstuffs when they are pregnant. So don't feel that you are unusual if your dietary intake doesn't alter much when pregnant. It is common for people to say that a craving is the growing baby's way of telling the mother what vitamins and minerals are needed. However, there is no proof that this is the case. Most scientists explain pregnancy cravings either because of the hormonal changes that are going on or because of psychological reasons.