Hormones in pregnancy

Pregnancy hormones, of which the most famous is undoubtedly beta-HCG , are essential in preparing the body for childbirth. Responsible for a number of significant changes, they are many and varied, and each of them has an impact on the body.

Even the mind and emotions are involved in this elaborate, fundamental “hormonal symphony” which marks the times of the entire gestation. Let’s get acquainted with the main hormones.

Beta-HCG and early pregnancy

It is undoubtedly the most famous hormonal component when thinking about pregnancy, if only because the presence of beta-HCG in the urine is the one that determines positivity in pregnancy tests.

In fact, present since about a week after conception, this hormone continues to be released in different dosages (i.e. the amount of presence in the blood) throughout the gestation, and then disappears after childbirth. It is produced by the trophoblast (the embryonic tissue which will then transform into the placenta) and, especially in the first

Estrogens in pregnancy

Always present in childbearing age, estrogens perform important functions during pregnancy : they promote the growth of the uterus and breasts, they soften the ligaments making the development of the “belly” more elastic, they promote blood flow to some organs of the mother and promote development of lungs, liver and kidneys of the child.

The increase in estrogen production in pregnancy is also responsible for some of its most common symptoms, such as an increase in breast volume, increased propensity for skin pigmentation, increased appetite and nausea.


Progesterone is another essential hormone in pregnancy, the effects of which are noticeable on many levels Produced by the placenta and corpus luteum and always present in women of childbearing age, it becomes essential during pregnancy. Firstly, it helps to make the endometrium able to accommodate the implantation of the egg, and throughout the gestation it keeps the uterus a hospitable, elastic and relaxed place for the baby, preventing contractions until it is time for delivery. labor.

Progesterone relaxes the smooth muscles of the body, which causes various side effects: swelling, belching, gastric reflux, constipation and gas production, due to a certain “softening” of the intestine and internal muscles connected to the stomach. Not only that: the blood vessels are also “relaxed” and dilated, with the consequent possibility of experiencing vertigo and dizziness. And the mind can also become very relaxed, this time due to the sedative effect of progesterone: daytime and above all post-prandial sleepiness depends precisely on this hormone.

On the other hand, progesterone also brings with it an increase in the growth of nails and hair during pregnancy, as well as a general state of well-being and tranquility: one of the mysteries of the famous “glow” (that serene luminosity) of many pregnant women. However, as with estrogen, swings in progesterone dosage can also cause irritability and mood swings.

Relaxina, thyroxina (T4 and T3) and calcitonina

As the name suggests, relaxin is a hormone responsible for relaxing ligaments, muscles and joints, leaving room for the baby’s growth and preparing the body for childbirth. The action of relaxin can lead to some pain in the lumbar and pelvic area. Thyroxine (T4 and T3) promotes the baby’s assimilation of nutrients and the development of its nervous system, while calcitonin protects the mother’s bone density, challenged by the growing baby’s demand for calcium.

The importance of oxytocin during and after childbirth

We close this list of the main pregnancy hormones (from which we have kept out for reasons of space other important names such as insulin, cortisol, and the two placental lactogen and adrenocorticotropic hormones) with oxytocin. Produced during and after childbirth to promote contractions, during breastfeeding it helps the smooth muscle of the nipple to contract. Also known as the “attachment hormone”, oxytocin would help promote the bond between mother and child on an emotional level.

Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform, Maternicity.com.

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