• Estrogen:

Estrogen is a hormone for controlling the reproductive system, playing a role in the maturation of a girl, menstruation, and conception. It also affects other parts of the body such as bones, blood vessels, heart, and brain. The majority of estrogen is made in the ovaries. A smaller additional quantity of estrogen is produced by peripheral tissues such as fat.

 
Ovaries start to produce estrogen when a girl reaches her puberty. In reproductive ages, a woman has highest level of estrogen. Ovaries produce less estrogen when a woman reaches 40 years old and stop producing estrogen when she reaches menopause. The average age of Thai woman to reach menopause is 45 – 51 years, often slightly earlier than Western women.
 
If both ovaries have been removed before menopause, types of changes in the body are the same as a standard menopause, but likely to be more serious because of the abruptness of the estrogen deficiency.
 
There are many types of estrogen in hormone replacement. The most popular one is bio-identical hormone. Hormone replacement is available in tablet, gel, patch, or vaginal ring forms. A doctor will make the decision which form is most suitable for each patient. 

• Progesterone:

Menopausal women need progesterone hormone mainly to prevent endometrial hyperplasia and endometrial cancer. Progesterone blocks DNA systhesis, cell division, and reduces estrogen
receptors. There are many types of natural progesterone. To prevent endometrial hyperplasia in women who receive estrogen replacement, the dose and duration of progesterone supplementation are important, and given only when necessary.

• Vaginal bleeding frequently occurs, and causes some women to stop using the HRT program. This mostly occurs during the first 3 – 6 months, and after consistent use of the HRT, vaginal bleeding will disappear.
• Breast pain appears only in the early days of receiving hormone replacement. The woman will feel less pain as time goes on, and the pain will eventually disappear.
• Migraine headaches.
• Weight gain: Most menopausal women easily gain weight. Hormone replacement by itself does not make a woman gain more weight. It is the woman’s daily life, especially the imbalance of eating, exercise, and slower metabolism, which causes most weight gain.