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Hormonal changes that happen during pregnancy

By Ajanta Sen

During pregnancy, your body goes through several changes to facilitate the growth of your baby. Each and every woman goes through same hormonal changes during her pregnancy.

Being a female, you have been bestowed with a tough, intuitive and an absolutely unbelievable body when you are on the way to produce another creature just like you. Your body knows what to do during pregnancy, without making you aware of the changes.

During the 1st trimester, a woman completely transforms the way she observes the world through her sense of sight, smell and savor. Changes in kidney and heart functions, weight gain and some physiological changes to breasts and uterus are some of the common changes that you can observe in your first trimester of pregnancy.

These changes are mainly due to the secretion of hormones from your placenta. These hormones are progesterone, estrogen, hCG, prolactin, cortisol, hPL, etc.

These sudden changes in your body could be very devastating, especially if you are working. If you are a working woman, these hormonal changes can make your normal schedule a bit more complex than it would be in general.

However, it is always advised to keep yourself informed on the different types of hormonal changes that happen during pregnancy. If you are aware of these changes, it will make you stronger and you can handle the situation with ease.

The article highlights all kinds of hormonal changes that happen during pregnancy. Thus, get acquainted with what all is happening or going to happen inside your body during your pregnancy:

hPL (or Human Placental Lactogen)

This is a type of hormone which is made by the placenta. The hPL hormone provides nutrition to the fetus as well as it plays a significant role in inciting the milk glands in your breasts during pregnancy (in the possibility of breastfeeding).


During pregnancy, the progesterone is secreted by your placenta and ovaries. The role of the progesterone hormone is to stimulate the thickening of the uterine lining in the probability of embedment of a fertilized egg.

The progesterone is produced from cholesterol. Initially, it is converted into pregnenolone and thereafter it turns into progesterone.


The role of estrogen hormone is to support the uterine lining, develop your breast tissues, enhance the blood flow to your uterus and rest of the body, calm down the smooth organs, etc.

The estrogen is formed by your placenta and ovaries during pregnancy. The cholesterol goes into your placenta and gets converted into pregnenolone and thereafter it turns into DHEA in the liver and adrenal gland of your fetus. DHEA comes back again into your circulation and turns into estriol with the help of aromatase (an enzyme).


There are 2 types of thyroid hormones which play a very important role during your pregnancy. The first one is the T4 hormone, which remains inactive. The other one is T3, which is the active hormone and is obtained from the T4 hormone.

When your estrogen levels are high, they encourage in high T3 and T4 hormones and support with regulation and metabolism of your steroid hormones.


It is also called the stress hormone. During pregnancy, when you are in your 40th week, the production of cortisol hormone from the adrenal gland of your baby also boosts. This boost makes your uterus very susceptible to contractions. This in turn raises the estrogen in your blood circulation and lessens the progesterone hormone, which encourages more contractions.


This is a hormone which incites the tissues of your breast during pregnancy in order to produce milk. The estrogen hormone encourages the secretion of prolactin from your pituitary gland to get ready for lactation.

However, you cannot expect to start lactating before delivery because the elevated levels of progesterone and estrogen hormones slow down the prolactin hormone from taking action on your breast tissues.

After your delivery, both your progesterone and estrogen levels reduce and hence prolactin can encourage lactation. When your newborn sucks your nipple, the prolactin hormone secretes to make milk.

If there is sufficient prolactin production in your body and you breastfeed regularly, then prolactin can be the best natural method for birth control. The reason is prolactin prevents ovulation.


This is the hormone which is produced by you during your pregnancy. The role of oxytocin is to widen the cervix and incite the tough uterine contractions in order to facilitate the delivery of your baby. After your delivery, this hormone is incited by your baby when he sucks your nipple and encourages the flow of milk.


When the egg breaks from your ovary, the outer coat of it (also known as corpus luteum) is left behind. Now, the role of hCG is to keep up the corpus luteum, so that it can produce estrogen and progesterone to encourage the embryonic growth.

If in any case your egg does not turn out to be a fertilized one and you don't make hCG, this will result in a slow disintegration of corpus luteum and you will get your menstruation.

The hCG hormone remains present throughout your entire pregnancy; however, it attains the maximum levels in your 9th and 10th week of pregnancy. This is the point when your placenta is capable of taking over the hormone production.

Read more about: hormones pregnancy
Story first published: Monday, June 25, 2018, 14:50 [IST]