Suit up! It’s time for war.

How pregnancy works and how we’re trying to fix it.

Pregnancy is hard. It’s a process that brings about many issues, some small and some big. I’ve also been told that pregnancy is one of the most rewarding experiences, but I think that’s just wishful thinking.

The War of Pregnancy

Pregnancy in the human body is much like wartime operation for nations. Every part of the woman’s body is mobilized in order to create an entirely new human. Some battalions are right on the front line. Some are fighting to keep morale up back on the home front. More still are readying the troops for a final, all-out offensive to end the war.

Alert! Alert! The egg has been fertilized!

The female body is always getting ready to reproduce. Every month an egg is released from one of the ovaries, leaving behind the corpus luteum. This structure secretes progesterone and estrogen (female sex hormones) in large quantities, getting ready for potential fertilization. If the egg remains unfertilized, the corpus luteum degenerates, progesterone and estrogen levels drop, and menstruation begins.

This is kind of like a practice drill. Every month, the body gets ready for a potential pregnancy. This way, the body is always ready if fertilization occurs.

If the egg is fertilized, the corpus luteum stays intact to keep hormone levels up. Progesterone and estrogen help prepare the uterus for pregnancy. They also alert the rest of the body:

Alert! Alert! The egg has been fertilized!

The fertilized egg will become a pinhead-sized ball of cells called a blastocyst in 5–6 days. It will eventually bury itself in the lining of the uterus, called the endometrium. Estrogen makes this lining to become rich with blood so the blastocyst can properly implant itself and get nourishment,

The real fast-actor in pregnancy is human chorionic gonadotropin. Its levels double every day (on average) for the first 10 weeks! Its main function is to stop further menstruation and form the placenta (stay tuned). It’s also what most home pregnancy tests look for.

The war is underway now. The organs on the front lines are directly involved with caring for the fetus. These include:

  • Uterus
  • Placenta
  • Cervix

In the normal female body the uterus is only about 7.5 cm x 5 cm (think ~the size of an orange). It has some of the strongest muscles in the female body. By the end of pregnancy, the uterus will grow to about the size of a watermelon! The uterus is (obviously) responsible for holding the fetus. It houses the amniotic sac which holds the fetus.

The placenta is an organ that only exists during pregnancy. That’s right: the body grows an entirely new organ. The placenta is a crucial supply line for the fetus; it supplies nutrients and oxygen and removes toxic waste products.

The cervix (meaning neck) is a ring of strong, thick muscle. The opening of the cervix is usually no wider than a straw, but the opening gets larger through pregnancy in order to allow for childbirth.

Recently, researchers at the University of Western Australia were able to successfully develop an artificial placenta! We’ll go into this technology in detail later.

In every war in history, communication has been instrumental. Likewise, the messengers in the human body are essential to the process of pregnancy.

The hormonal rollercoaster, taken from Khan Academy

These hormones are all known to us. These are the hormones that drive all sorts of the side effects of pregnancy.

Estrogen is responsible for a lot. It encourages the uterus to grow, maintains uterine lining, increases blood circulation and regulates the production of other key hormones. However, these effects can have some interesting side effects:

  • Stuffy nose — estrogen increases blood flow to mucous membranes, including those in the nose, and causes them to swell and soften. It can cause sinus congestion, runny nose and headaches.
  • Pregnant “glow “ — this is caused by increased blood flow to the skin. It can cause a rosy glow, but also red splotches and rashes, and itchy palms.

Progesterone helps keep the placenta functioning normally. It has a whole host of other functions too, like relaxing the pelvic bones in order to facilitate childbirth. This is done by inducing another hormone called relaxin (10x regular levels). However, relaxin doesn’t just act on the pelvis, it acts on bones and joints throughout the body. This is what causes many joint aches and pains, and what can cause pregnant women’s feet to grow.

So we’ve dealt with the front lines and the messengers, but what about the rest of the body?

The uterus is screaming “I NEED MORE SPACE!”

The rest of the body has to deal with all the consequences. Most side effects of pregnancy come from either hormonal changes (see above) or from the sheer space requirements. Human real estate is costly.

In fact, later in pregnancy, something called Supine Postural Hypotensive Syndrome (fancy) can happen. Supine postural refers to a certain body position, being lying on the back facing up. Hypotensive refers to low blood pressure, and syndrome is just something going wrong. Essentially, as the uterus grows, it starts compressing the inferior and superior vena cava as well as the aorta (the two main blood vessels coming into and out of the heart).

This happens literally just because the uterus becomes too big! If the mother lies on her back, the uterus blocks these pathways like a kid stepping on a hose. This causes blood flow to slow down, thereby decreasing blood pressure (not good). That’s ridiculous! It’s such a simple problem, and yet the grand Homo Sapiens still suffers from it.

The uterus squishes many, many more organs. It squishes the lungs, causing regular breaths to take in less air. Luckily our multi-talented friend progesterone takes care of this by increasing the amount of air inhaled in each standard breath.

The uterus also squishes digestive organs like the stomach, large intestine, liver and gallbladder. This can cause a whole host of unwanted side-effects, like constipation, gallstones and slow digestion. This comes partially from lower levels of the hormone gastrin, which stimulates secretion of stomach acid. Stomach acid, in turn, stimulates secretion of pepsin (don’t worry! there’s no quiz for all these terms). Pepsin is used to digest proteins, so lower gastrin = slow digestion.

Our old friend relaxin is back to wreak havoc once again, this time causing heartburn. Relaxin causes the cardiac sphincter (the opening between the stomach and the esophagus) to loosen, causing stomach acid to leak through and irritate the esophagus. This is in tandem with the fact that the uterus is already exerting pressure on the stomach, so acid reflux is almost guaranteed during the third trimester.

So! What’s the problem?

When we think about pregnancy, we think that it’s the result of a well-oiled system bringing life into the world. However, all these examples clearly show that human pregnancy is nowhere near perfect. As the human condition demands, we can make this whole process safer and easier! All the side effects I listed are just inconveniences, but what about miscarriage? What about anemia? What about stillbirths, where over half the cases have no known cause? Pregnancy isn’t just inconvenient, it’s dangerous.

For these nine months, females are biologically geared towards making a baby. That means that whatever else they do, be it leading a company, doing research, or pursuing higher education is no longer the biological top dog. Regardless of the position, it’s a biological fact that women are less productive during pregnancy.

Matrea — a better solution

Here at Matrea, we want to work on a better way to handle pregnancy: artificial wombs. Obviously this won’t happen overnight, but we believe thinking 10x is how we’re going to push the world forward.

  • Using and improving artificial placenta technologies (Usuda, Kemp, 2019), we will develop artificial wombs to help premature babies on the border of viability (20–24 weeks). Ex vivo (out of organism) therapy is an exciting new field ready to be developed now. This is our short-term goal.
Image taken from this study. This holds great promise since the artificial wombs are filled with amniotic liquid — unlike incubators, which are filled with air.
  • Our long-term goal is to facilitate pregnancy completely outside the uterus! We would start as a better alternative to surrogacy, eventually giving women more choice and flexibility when it comes to having a child!

This will require greater research and understanding of many different aspects of pregnancy. As you have undoubtedly seen, pregnancy is not as simple as growing a baby in a bag — but we’re never going to move forward solving solved problems. Matrea aims to revolutionize the way we think about pregnancy.

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