Understanding Your Hormones During Pregnancy

Understanding your hormones during pregnancy, may help you to appreciate the amazing event and miracle of creation in spite of some of the less endearing disorders caused by the symphony of finely tuned hormones of pregnancy. Pregnancy is one of the most amazing events of your life and brings with it many changes both physical and emotional to support and nurture your developing baby until full term.

Where do hormones originate?

Hormones are secreted by the endocrine system derived from the Greek ‘endo’ meaning inside and ‘crinis’ which is secrete. Their job is to trigger and regulate activity throughout our bodies. Our whole sexual health and fertility, the creation and continuation of pregnancy depend on our hormones.

Hormones released after implantation in the first trimester

The first trimester of pregnancy begins with conception, as the sperm unites with the egg. The embryo implants into the uterine lining (endometrium) and prevents the usual fall in oestrogen and progesterone, which occurs if fertilization does not occur. The first sign of pregnancy is usually a missed period.

Human Chorionic Gonadotrophin

HCG is produced by the chorionic villi after implantation of the embryo and stimulates the corpus luteum of the ovary to increase its production of progesterone to maintain the pregnancy until about 10-12 weeks when the placenta is mature enough to take over production. Levels of HCG peak at about 70 days and is the main hormone measured in pregnancy tests to confirm a positive pregnancy. Unusually high levels may indicate a multiple pregnancy. HCG is thought to be the hormone responsible for a number of early pregnancy symptoms including morning sickness and the overwhelming fatigue that some women experience.


Progesterone

Progesterone is one of the major hormones of pregnancy and is produced initially by the corpus luteum, followed by the placenta with a steady rise in levels until labour and birth when there is a rapid drop in levels. This drop may also be one of the triggers to facilitate the onset of labour.

During implantation and early gestation, progesterone appears to decrease your maternal immune response to help facilitate the acceptance of your embryo by your body. It decreases contractility of the uterine smooth muscle by preventing contractions to maintain your pregnancy. Some of the ‘minor disorders of pregnancy such as heartburn and constipation are also down to the relaxation of smooth muscles!

Progesterone in conjunction with relaxin also softens cartilage, which may contribute to the common ‘pelvic girdle discomfort’ that many women experience during their pregnancy as it progresses.

On the positive side many women find that their hair appears thicker and glossier, as progesterone stimulates your hair follicles to go into a resting phase.

Finally, high levels of progesterone inhibit prolactin during pregnancy, but may help to trigger milk production after birth due to its rapid fall at the end of pregnancy.

There are so many hormones working in harmony throughout your pregnancy that it is impossible for me to include them all in one article. Watch out for my next blog when I will continue to explore the amazing effects of hormones on pregnancy, birth and beyond.