At pregnancy week 13 the baby is now about the size of a peach i.e. 3 inches long and almost ¾ of an ounce, and will grow rapidly over the next few months. Although the baby's organs are formed they still need to mature over the following weeks. The hands and feet are fully developed and making lots of movements too as messages pass from the spinal cord to the muscles. The baby's head is still large but the neck is more defined. The arms and legs continue to grow longer, which makes them more in proportion with the rest of his body. Fine hair sprouts over his body. Because the baby's neck is now developed it can move its head freely. If the baby is seen on the ultrasound scan at this stage it is quite amazing to see him so active. By this time now the baby’s liver starts producing insulin, a hormone which helps the baby to regulate its blood sugar level with his growth and development. Fingernails develop and vocal cord starts to form. The baby’s sense of taste and smell continue to develop. The baby’s neck is growing longer and the space between the chin and the chest is increased. The placenta provides the entire baby’s nutrition right from the oxygen and nutrients. Placenta also produces hormones like progesterone and estriol. These hormones help to maintain the pregnancy.

How your body develops and changes

The morning sickness and other symptoms are gone away by now and the appetite returns. By pregnancy week 13 the uterus expands further which might cause some discomfort or mild cramping. Some women may also experience round ligament pain around pregnancy week 13 which is usually harmless. It is feeling of a short or brief sharp and stabbing pain along one side of the abdomen or the other. This usually happens when a woman is shifting positions quickly; that is moving from her side to her back or at times getting up suddenly. Most of this pain disappears within few minutes. If any other pain is noticed accompanied by other symptoms including bleeding or cramping health care provider should be contacted immediately. By pregnancy week 13 the risk for miscarriage drops significantly.

By pregnancy week 13 on the growing belly bumps forming on the breasts may be seen. These bumps are glands that help the breasts grow and develop during pregnancy. Prenatal vitamins should be continued in addition to eating a healthy diet. This ensures that the baby gets additional vitamins and minerals necessary for its growth and development. The mother should make sure not to take prenatal vitamin with foods containing calcium as calcium can interfere with the body's ability to absorb iron.

Everyday during pregnancy week 13 and ahead the mother should try to consume the following nutritional diet: Whole grains and vegetables, fruits, dairy products, proteins and water. Three to five servings of vegetables and two to four servings of fruits are ideal for adequate nutrition during pregnancy.

Eating right amount of calories lets the baby and the mother gain proper weight. Food high in folate such as orange juice, strawberries, spinach and fortified bread and cereals should also be included. Necessary supplements should be taken along with the healthy diet. The diet should include enough vitamins, minerals like folic acid, iron, calcium and zinc. The mother should also take ample rest and also buy some maternity clothes which are comfortable during pregnancy.