What Physiological Changes Occur during Pregnancy?

By (embryologist) and (fertility counselor).
Last Update: 11/07/2014

The function of the physiological changes during pregnancy is to prepare the body for the condition of becoming a mother. Some of them are the increase in the blood flow and the changes on the breasts tissues. Breasts are of vital importance during the first months of the baby once he’s born.

Provided below is an index with the 4 points we are going to expand on in this article.

Estrogenic and luteal hormone

During gravidity there’s an increase in the levels of estrogenic and luteal hormone that stimulate the gland development. Breasts tend to get more rounded due to the development of adipose tissue that can be found within them.

Breast sensitivity is one of the first symptoms of pregnancy and it usually begins between the fourth and sixth week of pregnancy and it lasts up to three months after the baby is born.

Sebaceous glands in the nipple

During the first months breasts become ample and their size increases. Aureole and nipple’s skin pigmentation increases considerably and some small bulges may appear, named Morgagni’s tubercles, due to the development of the sebaceous glands.

The blood irrigation in the breasts increases and the superficial veins are visible. This effect could even increase during breastfeeding.

Colostrum before delivery

During the third month of pregnancy, breasts produce a substance named colostrum, a special milk that will provide the baby with protection against infections during the first days of life.

During the breastfeeding period the changes that happened during pregnancy tend to continue. At the beginning of the breastfeeding period and during the first hours, the continuous sucking attempts of the baby provoke the expulsion of the colostrum, which is yellowish, dense and has a lot of cholesterol.

Properties of first milk

The choice of the bra is of vital importance during this period: it has to be soft, better if it’s made of cotton, and it has to provide good fastening. A good choice would be buying a breastfeeding bra, for you would use it to feed the baby. When buying bras, it must be taken into account, the fact that breasts will continuously increase their size during pregnancy.

Properties of the colostrum

As we stated before, the colostrum is rich with cholesterol, dense and yellowish. It is a special milk that contains lots of amino acids and plays a vital role in the growth and development of the baby. The colostrum also contains antibodies, which are in charge of preventing the infections.

Proteins, vitamins and cytokines are other properties of the colostrum that will be beneficial for the baby during his first months of life. Glycoproteins make it possible for growth and immune factors to traverse the digestive tract, preventing them from being digested.

We make a great effort to provide you with the highest quality information.

🙏 Please share this article if you liked it. 💜💜 You help us continue!


 Neus Ferrando Gilabert
Neus Ferrando Gilabert
B.Sc., M.Sc.
Bachelor's Degree in Biology from the University of Valencia (UV). Postgraduate Course in Biotechnology of Human Assisted Reproduction from the Miguel Hernández University of Elche (UMH). Experience managing Embryology and Andrology Labs at Centro Médico Manzanera (Logroño, Spain). More information about Neus Ferrando Gilabert
Adapted into english by:
 Sandra Fernández
Sandra Fernández
B.A., M.A.
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

Find the latest news on assisted reproduction in our channels.