For the remainder of this article, I will use IVF and in vitro fertilization interchangeably.
One of our prime directives as human beings is to “go forth and multiply”. This natural urge is built into the vast majority of us and is probably the main reason why many of us like sex so much. Our urge to procreate is a good thing because the human race would have died out eons ago without it. Anyhow, even though we humans are wired to procreate, we aren’t always successful at it for a variety of reasons. Among these reasons are: a loss of feminine fertility with increasing age, low sperm count, etc. As we’ve seen many times throughout the history of mankind, we aren’t very good at accepting our limitations and are thus prone to fighting like hell to overcome them. In the struggle to overcome the limitation of poor fertility, we discovered what is known as “in vitro fertilization” which is the central theme of this article.
So… what the heck does “in vitro fertilization” mean? Well “in vitro” is latin for “in glass” and back in the day, laboratory utensils and equipment were made of glass. So in vitro fertilization is the technical term for a procedure that allows for the fertilization of a human egg in a laboratory dish rather than in the female reproductive tract. Having read that, you might be thinking whoa! Really? I’m here to tell you yes… really. The next logical question that is probably bouncing around in your head is – so how does all this medical/scientific voodoo work? Fair question… grab a snack and a glass of wine (if you’re old enough) and let’s see if we can make sense of this in vitro fertilization thing.
At some point in our adult lives, most of us decide to share our lives with a special someone. Eventually, most of us want our own children to be part of this union so we discontinue the use of contraceptives (condoms, vaginal rings etc) at strategically chosen time points in our sexual relationships.
For a small percentage of couples it becomes apparent that something is wrong after a year or two of unprotected sex without a positive pregnancy test. This is usually when couples decide to consult a reproductive endocrinologist or an infertility doctor to get at the root cause of the problem.
After several blood tests designed to monitor female hormone levels as well as other tests to verify sperm counts and sperm shape, a reproductive endocrinologist may suggest in vitro fertilization as a viable means through which the couple can overcome their infertility problem. Let’s now take a look at the distinct steps that a couple may typically go through in the in vitro fertilization process.
Steps of the in vitro fertilization process
Harvesting the Sex Cells
“Ovulation” is the technical term for the process through which women produce egg cells. Under normal conditions, the average woman will produce one egg every month. Oh and by the way, it’s no accident that women also usually go through menstruation once every month… the two (egg production and menstruation) are linked. Anyhow this natural ovulation process is facilitated by an increase in a hormone called estrogen which triggers a sudden increase in another hormone called “Luteinizing Hormone” (LH). This spike in the quantity of Luteinizing hormone causes the ovaries to release an egg. This is how it works under normal conditions, but for those of us dealing with infertility, one egg doesn’t quite cut it so modern medicine has devised a means to improve the odds.
To improve the odds of actually getting a fertilized egg, the woman is often given some form of luteinizing hormone in addition to what she naturally produces to boost egg production. So instead of just producing one egg, she now produces multiple egg cells, improving the chances that at least one of them will get fertilized. Just so you know, ovulation usually occurs anywhere between 24 and 36 hours after the spike in LH quantity. At this stage of the process, the woman will go through regular procedures that allow the doctor to use fancy imaging techniques to monitor the state of her reproductive organs just to make sure nothing goes terribly wrong.
For the woman…
OK, assuming superovulation went well, the medical professional now has to somehow collect the eggs produced by the woman. To this end a small surgery known as “follicular aspiration” is performed. Follicular aspiration sounds complicated to me so if it’s alright with you, let’s stop for a moment and break it down. The “Follicular” part of follicular aspiration refers to ovarian follicles. In plain english, you can think of an ovarian follicle as a tiny sac in the ovaries of woman that has the potential to mature and release a single fertilizable egg. In plain english, the word aspirate means “to draw fluid by suction from a vessel or cavity”. So when we stitch both of these words together, follicular aspiration simply means that with the help of high tech imaging techniques, the infertility doc will very carefully insert a needle connected to a suction device through the vigina to reach the ovarian follicles where he or she will then retrieve some fertilizable eggs. Thank God for anaesthesia because without it, this would be a seriously painful procedure. There may be some cramps after the procedure is completed, but these usually go away within a day. If there are no serious complications from this procedure, the patient can usually go home the same day.
For the man…
The process of harvesting male sex cells is a lot less complicated. The man in question is simply given a plastic cup with a screw cap, some pornographic magazines, and locked up in a closet to do the business if you know what I mean.
At this point in the procedure, a sufficient number of both male and female sex cells have been retrieved. Now then, the challenge is to somehow get a few of the male sex cells (sperm) to fertilize a few of the female sex cells (egg). To make this happen, trained laboratory scientists use a high powered microscope to fish out healthy looking sperm cells and inject each chosen sperm cell right into a healthy egg with a stupendously steady hand. A lot of IVF clinics fertilize multiple eggs during this step to increase the chances of at least one surviving. The fertilized eggs are then placed in a laboratory dish which contains the optimal chemical environment to foster development. Trained laboratory scientists who know what to look for will examine the fertilized eggs on a daily basis to make sure they are developing as expected and those that didn’t quite make it get discarded according to procedures recommended by the regulatory system.
Once a healthy fertilized egg divides, it becomes an “embryo” which just means “fertilized egg in the process of development”. After about 3-5 days, laboratory technicians should be able to detect signs of cell division through the magnifying lens of an ultra powerful microscope. This is when the team of healthcare professional and prospective parents has to decide which of the healthy embryos to implant into the womb.
I’m guessing you already know that we have this biological code called DNA that contains “genes” – a set of instructions that govern our physical and mental makeup. Nature in her infinite wisdom made this code redundant so that all of us have two copies of each gene. In some cases, one of the genes at a given locus is busted for whatever reason… mutation, bad luck, life, whatever. If the busted gene happens to be what we call “autosomal recessive” the individual won’t show any physical signs of illness because the second copy of the gene at that same locus can compensate for this loss. However, if both parents pass on their busted copy of the same gene to their child, that child will have a physical manifestation of a disease. A good example of this is the sickle cell trait. For example, a few of my siblings have one busted sickle cell gene, but none of us have two busted copies. As a result, none of us actually have the signs and symptoms of the sickle cell disease. You might be wondering what all of this has to do with in vitro fertilization… stick with me, I assure you that there is method to the madness.
So remember how we ended the previous step/section by hinting that the team of healthcare professional and prospective parents had to select which pair of embryos to implant into the female’s womb? Well, genetic screening is actually a big part of that. Laboratory techniques have come so far such that a few cells can actually be retrieved from an embryo and tested for it’s eventual sex as well as the incidence of genetic diseases. If a genetic defect such as the sickle cell disease, or the incorrect amount of DNA is discovered in one of the embryos, the team may choose to avoid that embryo during implantation. This method of selecting a few cells from a developing embryo and testing them for the incidence of a genetic disorder is called “pre implantation genetic screening” (PGS). In plain english, that big sounding term just means that before (pre) we implant an embryo into your womb (implantation), we’ll run tests on it to make sure it checks out genetically (genetic screening).
This is the anchor leg of the in vitro fertilization journey. After fertilization and screening the doctor will insert a catheter (thin hollow tube) containing the embryos into the womb. If an embryo sticks to the lining of the womb and grows, then “bob’s your uncle” people… we’ve got a happy pregnant couple!
I should mention here that more than one embryo is usually implanted at this time in order to improve the chances of at least one of them developing into a baby. This is why in vitro fertilization yields fraternal twins and triplets with more regularity than the natural mode of conception.
The graphic below is a nice high level visual summary of the IVF process. Feel free to refer back to it as many times as you want.
Interestingly, if there are still healthy embryos left over after the IVF process is complete, they can be stored at ultra low temperatures for years. In 2014, I visited an IVF clinic here in the San Francisco bay area and learned of a baby that had been born through IVF using a 20 year old embryo! So when this kid celebrates her 1st birthday, is she 1 or 21 years old? Super weird… I know, but a very valid question all the same.
There are a lot of folks who have a problem with the ethics of IVF. “Why are these scientist nerds trying to play God?” Is the question I have heard more times than I wish to recount. While I can see where such people are coming from, to focus on that to the exclusion of everything else related to IVF is to entirely miss the point. Yep, scientists have egos, but IVF is actually a mini miracle that has helped a lot of well adjusted wonderful people to realize their desire for a healthy family. We should actually all be thankful that something as insane as IVF actually exists in our current reality so that people can have much more control over their reproductive destinies. From all of us here at chubaoyolu.org, take care of yourselves and each other.
Oyolu B.C. Ph.D.
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