Hormones play an important role in a woman's bodily adaptations to pregnancy. The four major hormones involved are progesterone, estrogen, human chorionic gonadotropin (hCG), and relaxin.
Progesterone is responsible for maintaining the endometrium of the uterus, which prepares it for implantation of the fertilized egg. It also helps to relax smooth muscle tissue throughout the body, including those in the gastrointestinal tract, helping to reduce symptoms such as nausea and constipation that can occur during pregnancy. Estrogen helps with fetal development and stimulates growth of maternal tissues, like the breasts and uterus. hCG is produced by cells that will eventually form the placenta and helps to sustain early pregnancy. Relaxin helps to soften the ligaments in a woman's body, allowing for it to expand as the baby grows during the pregnancy.
These hormones are responsible for many of the changes that occur in a women's body during pregnancy. They work together to increase blood supply and relax muscles, allowing organs and tissues to adjust so they can accommodate the growing baby. This can lead to an increase in breast size as well as abdominal enlargement and stretching of other structures such as the skin and pelvic muscles. Changes in hormone levels may also cause mood swings, fatigue, cravings for certain foods, and increased sensitivity to smells. In addition, hormonal fluctuations can contribute to morning sickness during early stages of pregnancy.
Altogether, these hormones play a critical role in the bodily adaptations that occur during pregnancy. They help to make sure that the mother and her baby are healthy, as well as allowing for comfortable and safe development. Without these hormones, pregnancy would be impossible.