Week 13

Week 13

Your Baby

How big is my baby?

This week you baby is approximately 65-78mm (2.6-3.1 inches) long and weighs about 14-20 grams (0.5-0.7 ounces).

This week your baby starts to grow rapidly, and his/her body is now growing faster than the head. Maturation of the tissues and organs continues. The heart is beating at about twice the rate of a normal adult heart and can be detected by using an ultrasonic device or Doppler.

Your Pregnancy

What pregnancy symptoms will I be experiencing?

A pregnancy is divided into three parts, each of which is called a trimester. Week 13 is the start of the second trimester (weeks 13-28). The third trimester covers from week 29 to the birth of your baby.

You may notice slight weight gain as the baby and its support system grows rapidly. Your uterus now fills your pelvis and future growth will mean that your uterus expands up into your abdomen. Your fluctuating hormones may also start to settle down, allowing you to feel less emotionally unbalanced and sensitive.

Other hormone changes in pregnancy tend to increase the pigmentation of a woman's skin. Some dark skinned women can get a butterfly-shaped patch of pigmentation over their face, known as chloasma. All marks are a temporary condition and disappear soon after the baby's birth. Your skin may also become drier or oilier during pregnancy. Some women may also develop a linea nigra, which is a darkly pigmented line that runs from the umbilicus to the pubes. This is also due to hormone changes and disappears soon after birth.

Stretch marks occur when the skin becomes over-stretched and it loses its elasticity. Stretch marks can't really be avoided, although an excessive weight gain can increase them. Some women get no stretch marks at all and others get more than their fair share. The marks may appear on your abdomen, breast, hips or buttocks, and usually fade once the baby is born to thin silvery lines that hardly show. Using creams and lotions will help to relieve the itching and dryness associated with stretch marks.

Learn more about your pregnancy

Would you like weekly updates on your pregnancy? Sign up here to receive this information in your inbox.

Read more information on Pregnancy and Birth on Essential Baby.

Discuss Pregnancy in the Essential Baby Forums.