Understanding your Hormones During Pregnancy Part 2

Welcome back to my blog. I hope you enjoyed my first article on hormones and I am sharing the second one with you today. I have found the whole subject fascinating and I am overawed at the complexity of our hormones throughout our life events.

Mother nature in her infinite wisdom has created a complex system of hormones to nurture and support us throughout pregnancy and childbirth. This week I am focusing on the hormones that are involved in the finale of pregnancy and childbirth.

Relaxin

• Belonging to the insulin family relaxin is a protein hormone produced by the corpus luteum, breasts and placenta
• During pregnancy relaxin is found in ten times its normal concentration
• It relaxes smooth muscle, joints and ligaments, and promotes dilation of blood vessels in organs and tissues including the uterus, mammary glands and heart
• Reaches peak levels at 14 weeks and again at delivery
• Contributes to symptoms of heartburn, and pelvic girdle discomfort
• Relaxin helps increase the space for baby to pass through the birth canal
• It also soften and lengthens the cervix
• High levels are found in women with type1 diabetes as well as twin pregnancies
• Effects can last up to 5 months post delivery

Oxytocin

• Oxytocin is commonly known as the ‘love’ hormone as it is released in pulses during lovemaking, childbirth and breastfeeding, and engenders emotions of love
• Produced by the Hypothalamus and stored in the posterior Pituitry gland
• Outside the brain oxytocin-containing cells have been identified in diverse places including the placenta, thymus, adrenal medulla, pancreas and retina
• Oxytocin causes the rhythmic uterine contractions of labour, and levels soar towards the end of labour stimulated by ‘stretch receptors’ in the vagina as baby descends
• It is also responsible for the ‘fetal ejection reflex’ at the end of childbirth facilitating birthing quickly and easily at the end of an undisturbed labour
• These high levels also benefit your baby as they cross the placental barrier and switch off baby’s brain cells reducing the amount of oxygen required during labour
• Following delivery oxytocin stimulates the ‘placental ejection reflex reducing the risk of haemorrhage and also triggers the ‘milk ejection’ or ‘let down’ reflex in breastfeeding
• Your baby has also been producing oxytocin so that crucial bonding is initiated between you both, enhanced by skin to skin touching
• Suckling at the breast stimulates more oxytocin to be produced via the hypothalamus
• Oxytocin promotes feeling of contentment, a reduction in anxiety and feelings of calmness
• High levels of ‘stress hormones’ interfere with oxytocin levels during labour and may cause a delay in progress
• Synthetic oxytocin does not cross the blood/brain barrier except in small amounts therefore, does not have the same euphoric effects as natural oxytocin

Each hormone has its own unique and vital part to play in our ability to procreate, nurture, support and protect our babies during pregnancy and childbirth. Each one is vital, and although the side effects are not always pleasant, it is reassuring to know they are there for a reason. In my final article next week we will be looking at beta-endorphins and prolactin.

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.