What You Need To Know About Hormones In Pregnancy and Their Functions

Pregnancy is a roller-coaster of emotions, and the wheels of this roller-coaster are none other than pregnancy hormones. From giving you thick shiny hair and flawless skin, to making you cry at the sight of a puppy and so much more, what are the main hormones in pregnancy and their functions? 

The main hormones in pregnancy and their functions: An overview 

While the body produces many different hormones, pregnancy involves a set of unique hormones, each with specific tasks. Let’s take a look at the main hormones in pregnancy and their functions. 

1. Human chorionic gonadotropin (HCG)

What makes those two little blue lines pop on your positive pregnancy test? HCG! It’s perhaps the most important of all pregnancy hormones and produced exclusively during this time by what eventually becomes your placenta. 

Typically, your levels of HCG will rise eight days after ovulation, peak at 60 to 90 days, then drop slightly. 

During your first two weeks of pregnancy, HCG levels will double every two days. It is present in both your urine and blood, and it is this that is picked up by both urine and blood tests, confirming a pregnancy. 

The role of HCG

• It stimulates the production of progesterone and estrogen, two other important pregnancy hormones. 
• HCG suppresses your immune system in order to support your developing baby. Basically, it announces the presence of your baby to your body, and helps your womb get ready for its tiny guest. 
• This hormone is also responsible for telling your ovaries to stop releasing and maturing an egg every month.
• It is believed that rising levels of HCG are responsible for morning sickness — which subsides as your HCD levels go down. 

2. Progesterone

Progesterone is a regular female hormone produced by a cyst on the ovary known as the corpus luteum. But by about the tenth week of pregnancy, the placenta takes over the production of progesterone.

This hormone is crucial to establish and maintain a healthy pregnancy, and levels of it rise dramatically in the first trimester. 

Role of progesterone

• Even before you are pregnant, it stimulates the growth of your uterine lining in preparation to receive the fertilised egg. 
• It encourages the growth of breast tissue in preparation for breastfeeding, while preventing lactation. 
• Progesterone helps prepare you for labour in late pregnancy, by softening ligaments and cartilage.
• It suppresses your immune system so that it tolerates the foreign DNA of your developing baby. 
• This hormone stimulates glands in the endometrium to release nutrients for your tiny embryo to grow. 

3. Estrogen

Similar to progesterone, estrogen is also secreted by the ovary, until the placenta takes over. It steadily increases until the end of your first trimester, after which it plateaus. Estrogen has several, incredibly important roles in your pregnancy. 

Role of estrogen

• Estrogen helps your uterus grow.
• It regulates the production of other important hormones, including progesterone.
• Plays a crucial role in the development of your baby’s organs. Without it, your baby’s lungs, liver and other organs cannot grow. 
• It helps protect your pregnancy by preventing miscarriage.

4. Oxytocin

Also known as the happy hormone and love hormone, this is the hormone that triggers labour by kick-starting contractions. 

Role of oxytocin

• This hormones promotes bonding between you and your baby soon after he or she is born. 
• It stretches your cervix in preparation for birth. 
• Oxcytocin stimulates your nipples to produce milk. 

5. Human placental lactogen (hPL) 

During pregnancy, the placenta starts to produce this hormone around the second week The highest levels of hPL occur during the latter stages of pregnancy. 

Role of hPL

• Helps supply energy to your developing baby, to fuel his or her growth. This is done by regulating your metabolism, enabling your body to break down fats better, converting them to energy/ food. 
• Makes your body less sensitive to insulin. Insulin is responsible for shifting glucose from your bloodstream to cells. In effect, there is more sugar left in your blood to nourish your baby. 
• Stimulates milk glands in the breasts in preparation for breastfeeding after baby’s birth

6. Prolactin

This is another important hormone that helps with milk production. In fact, during pregnancy, it increases 10-20 times its normal amount. 

Role of prolactin

• It causes your breasts to increase in size, promoting growth of your breast tissue. 
• Prepares breasts for lactation and the release of milk. 

7. Relaxin

Much like its name suggests, this hormone has an important, “relaxing” role on your body during pregnancy. While it is present and produced by the ovaries in non-pregnant women, during pregnancy, the placenta and uterine lining boost the production of relaxin. 

Role of relaxin

• Prepares the uterus and its lining for pregnancy. 
• Relaxes the uterus wall to prevent contractions, which can obstruct the implantation process of a fertilized egg. 
• Prevents early contractions, helping to retain the pregnancy and avoid miscarriage. 
• It relaxes your blood vessels to help them cope with the increased blood volume you produce in pregnancy. 
• During labour and delivery, relaxin stimulate the softening of the cervix. It also relaxes the ligaments of your pelvis for a smoother delivery. 

Also read: The stages of labour

References: John Hopkins Medicine, Stanford Children’s Health