5 Hormones of Pregnancy and functions

In our previous posts, I have discussed pregnancy: signs and symptoms with diagnostic tips, physiological changes during pregnancy, and complications of pregnancy with their treatments. I will discuss today those hormones of pregnancy responsible for inducing physiological changes in a woman’s systems during pregnancy. Pregnancy hormones  play these roles in order to make the woman’s body or uterus conducive for the growing and developing foetus.  Without functions of these hormones, miscarriages are likely to result in. 

Hormones are the biochemical messengers of the body. They are produced by ductless glands, majorly the endocrine system and produce their effects on the targeted organs. Hormones in pregnancy are what produce the physiological and anatomical change in the body of a woman during pregnancy. Here they are:

Human chorionic Gonadotropin (hCG)

The trophoblast secretes HCG in early pregnancy.

This hormone stimulates progesterone and estrogen production by the corpus luteum to maintain the pregnancy until the placenta is developed sufficiently to assume that function.

 Human Placental Lactogen (hPL)

hPL is also called human chorionic somatomammotropin produced by the syncytiotrophoblast.  It is an antagonist of insulin. It increases the amount of circulating free fatty acids for maternal metabolic needs and decreases maternal metabolism of glucose to favour fetal growth.


It is secreted originally by the corpus luteum, then by the placenta stimulates urine development to provide a suitable environment for the fetus.

Oestrogen helps to develop the ductal system of the breasts.


It is also produced initially by the corpus luteum, then by the placenta.

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Progesterone plays the greatest role in maintaining pregnancy.

It maintains the endometrium and inhabits spontaneous uterine contractively preventing spontaneous abortion.

Also helps  to develop the acini cells and lobules of the breast in preparation for lactation.


Relaxin is a polypeptide hormone weighing about 6000 Da. It is detected in the serum of a pregnant woman at 7-10 weeks gestation and was first described in 1926 by Frederick Hisaw. Its peak occurs within 36-38 weeks of gestation.

Relaxin inhibits uterine activity, diminishes the strength of uterine contraction, and aids in softening of the cervix.

The hormone relaxes the mother’s muscles, joints and ligaments to make room for the growing baby. 

The effects of relaxin are highly concentrated around the pelvic region; softening the joints of the pelvis can often lead to pain in the area.

In preparation for childbirth, it relaxes the joints and ligaments in the pelvis and softens and widens the cervix.

Its primary sources are the corpus luteum of the ovary and placenta.

Having the understanding of pregnancy hormones help you to tolerate the minor complaints of pregnancy and to become an expert in your own health.   See how pregnancy hormones are causing complications of pregnancy. Thanks for your time. Share to your family and friends.