is mature enough to take over oestrogen and progesterone production.

Oestrogen

This hormone causes the breast tenderness and enlargement, which are typical of early pregnancy. It is produced throughout pregnancy, and helps to regulate levels of progesterone and prepare the womb for the baby and the breasts for feeding.

Progesterone

Prevents the womb from spontaneously aborting the fetus by building up the lining so that it can support the placenta, and by preventing the natural movement and contractions of the womb. This is the hormone, which is responsible for the loss of interest in sex during pregnancy.

Prolactin

It is produced by the pituitary gland. It is responsible for the increase in cells, which produce milk within the breasts. Progesterone and oestrogen actually prevent milk from being produced. Immediately after birth, the levels of these hormones drop dramatically, allowing prolactin to stimulate the initial production of milk. Suckling also controls milk production.

Relaxin

It is found early in pregnancy and is responsible for helping limit the activity of the womb and soften the cervix in preparation for delivery.

Oxytocin

It is involved in reproductive behavior in both men and women, and apparently triggers "caring" behavior. It is also the hormone, which allows contractions of the womb during pregnancy and labour. Contractions felt during breast-feeding are also due to oxytocin.