Pregnancy hormones can turn you into that crazy lady so many husbands fear. From mood swings to blemishes, hormones take you on a crazy ride for the next 40 weeks of your life. When you look back, it can be comical at times. Commercials or simple thoughts can send you into crying fits. Or, your husband could send you off the deep end with one word.

Pregnancy hormones are intense. There are many different ones running through your body during pregnancy than any other time. It is important to understand them and how they might affect your life. There is so much going on in your body. Don’t you want a sneak peek as to why dog commercials make you bawl? Let’s look.

Human Chorionic Gonadotropin

The first pregnancy hormone that you need to understand is HCG, the main pregnancy hormone. In fact, this hormone is the only reason you will know that you are pregnant if you use a home test. When you test with urine, it looks for HCG in your system.

HCG is an interesting hormone. It only happens inside of your body when the fertilized egg implants in your uterine wall. Implantation doesn’t happen immediately. First, the egg has to be fertilized via sperm. Next, it slowly travels down the fallopian tube, a process that can take a week on average. Once it leaves the tubes, it has finally entered your uterus. Even once it reaches the final destination, implantation won’t happen immediately. It still can wait a few days.

Soon, the fertilized egg implants in the uterine wall. At this point, you are pregnant, and your body begins to produce HCG. This hormone is important for the growth of your new baby. HCG is made by the placenta and helps to sustain the pregnancy in the first trimester. At the end of your pregnancy, HCG will be lower because your body relies on it less.

Home pregnancy tests typically detect pregnancy once your HCG levels reach 25 mIU/ml. It can take up to 14 days post ovulation for your levels to reach this point. HCG doubles every 48 to 72 hours. This is why you can take a test one day, resulting in a negative. Then, the next day it could be positive. The hormones hadn’t yet reached the point needed for detection.

Normal Levels of HCG

One interesting thing about HCG is that the level you experience is different for everyone and every pregnancy. Your levels for your first child can be entirely different than your second. Because of this, there is a wide range of what is considered normal. Here are the general guidelines based on weeks since last monthly period (LMP).

  • 3 Weeks: 5 to 50 mIU/ml
  • 4 Weeks: 5 to 426 mIU/ml
  • 5 Weeks: 18 to 7,340 mIU/ml
  • 6 Weeks: 1,080 to 56,500 mIU/ml
  • 7 to 8 Weeks: 7,650 to 229,000 mIU/ml
  • 9 to 12 Weeks: 25,700 to 288,000 mIU/ml
  • 13 to 16 Weeks: 13,300 to 254, 000 mIU/ml
  • 17 to 24 Weeks: 4,060 to 165,400 mIU/ml
  • 25 to 40 Weeks: 3,640 to 117,000 mIU/ml

You will notice as you come to the third trimester, your levels of HCG will gradually decrease. Your body relies on HCG less to sustain the pregnancy. It is totally normal to have a lower HCG level at the end of your pregnancy.

It is important to remember that these numbers are simply considered guidelines. The most important factor is that the numbers are doubling every 48 to 72 hours. If your doctor orders bloodwork, he will want to see an increase within three days. A lower number doesn’t necessarily indicate that something is wrong, but the failure to increase is a problem.

Results of HCG

When you think of pregnancy, what is the one sign that you imagine? It is likely morning sickness. That one sign is what every woman dreads and hopes they are luckily enough to avoid. Whoever named morning sickness probably didn’t have it. We all know that it can last throughout the entire day, making the first weeks of pregnancy pure misery. No matter how you experience morning sickness, you can thank your rising levels of HCG.

HCG is rapidly produced throughout the first weeks of pregnancy. You start off between 0 to 4 mIU, a negative level. By the time you reach eight weeks pregnant, your levels could be as high as 225,000! That is a dramatic change in a short period.

There are more signs that happen during the first few weeks of pregnancy. Bloating, frequent urination and food aversions are just a few you might experience. Some women notice that their immune systems are weaker, leading to frequent colds. Thankfully, most of these signs decrease as you enter the beloved second trimester.


Progesterone is a very important hormone, especially during the first weeks of pregnancy. In fact, a low level of progesterone can lead to a loss. Progesterone is similar, in some ways, to HCG, but it has unique features and functions. Your ovary produces progesterone. Levels that are too low can weaken your uterus, resulting in a pregnancy that doesn’t progress as it should.

There are other functions of progesterone, such as aiding your immune system as your child grows inside. Your body wants to try to keep you as healthy as possible. Progesterone can help ensure your body realizes that the baby is supposed to be there. Sometimes, your body thinks pregnancy is a foreign invader, leading to an attack on the fetus. Progesterone prevents this from happening.

Pregnant women also get to experience that not-so-lovely sides of progesterone. When you’re feeling yucky during pregnancy, chances are you can thank this hormone. It can cause gas, acid reflux, dizziness, constipation, hair growth, and nausea. No one wants any of these things!

Estrogen – The Female Hormone

Most women know estrogen is the female hormone inside of your body that plays an important role during your pregnancy. Estrogen is responsible for the growth of your body That is a serious part! Your baby’s adrenal glands are unable to grow without the aid of estrogen. It is also responsible for the enhancement of your uterus and your child’s organ development. The increase in estrogen allows the uterus and placenta to increase blood movement and the transfer of nutrients.

Just like any other hormone, there are side effects to estrogen that aren’t as appealing. The supposed pregnancy glow can feel like eons away as estrogen destroys all that you created. Spider veins increase, as well as your appetite. You may welcome back your appetite after the dreadful first trimester. Despite the negative side effects, estrogen is a necessary evil, and it means your child is growing properly.

Estrogen is an interesting hormone. Every female natural has it in her body. Interestingly, you can produce more estrogen during ONE pregnancy than you would throughout your entire life without pregnancies. Estrogen is already present in your system before pregnancy, and it continues to increase gradually. The peak is reached during the third trimester. Without estrogen, your milk ducts may not enlarge and prepare for the birth of your child. What an amazing hormone our body creates!


If there is one hormone you want to have in your system later in pregnancy, it is oxytocin. Oxytocin is a hormone released by the pituitary gland inside of your brain. During pregnancy, oxytocin plays a shining role during labor and delivery, the goal for all pregnancies. This hormone leads to labor contractions.

Oxytocin directly leads to labor. So, unless you want to be pregnant, you will welcome a flood of these pregnancy hormones. As you near the end of your pregnancy, oxytocin works to prepare your cervix for childbirth by stretching and softening it.

Once you have your baby, you may notice contractions as you breastfeed. Oxytocin is also released when breasts are stimulated either by suckling or pumping. As your milk moves through the ducts, your body releases oxytocin. While breastfeeding, you are sure to notice contractions for the first few days as your uterus goes back to down to normal size. However, oxytocin will also make you sleepy. If you start to drift off while breastfeeding, it is very normal and caused by the hormone oxytocin.

The great thing about oxytocin is that there is little downsides. If you need Pitocin during labor, it is simply a synthetic form of oxytocin. When you have sexual intercourse, your body naturally makes it. If you go overdue, some women swear that natural stimulation sent them into labor due to oxytocin creating contractions.


It is no wonder that pregnant women are known to be slightly emotional during pregnancy. Women have such a large increase in pregnancy hormones. These hormones manifest themselves in a variety of ways, from bloating to acne. You may feel weepy or love life more than ever before. You may be sicker than a dog or feel ready to run races. Pregnancy hormones affect everyone differently. However, no matter who you are, they play a vital role in the development of your growing child.