In Vivo vs. In Vitro Fertilization: Key Differences Explained

Fertilization is the process where a sperm and egg unite to form an embryo. While fertilization naturally occurs inside the body, advanced fertility technology has made it possible to fertilize eggs outside it too! In this blog, we break down the differences between in vivo vs. in vitro fertilization (fertilization inside vs. outside the body) and help you understand which one may be more relevant to your fertility journey.

What Does In Vivo Mean?

‘In vivo’ refers to the Latin for ‘within the living’. It is used to describe when something is performed inside a living organism. In In vivo fertilization, the sperm fertilizes the egg inside a female body. The fertilized egg then makes its way to the uterus through the fallopian tubes.

Types of In Vivo Techniques

While natural conception is the most common form of in vivo fertilization, other techniques like IUI, AI, and GIFT also make use of the natural process of fertilization.

(1) Natural Conception

This is the most common form, where sperm travel through the woman’s reproductive system and fertilize the egg in the fallopian tube.

(2) Intrauterine Insemination (IUI)

A fertility treatment where sperm is directly placed into the uterus, increasing the chances of fertilization in the fallopian tubes.

(3) Intracervical Insemination (ICI)

Intracervical insemination (ICI) is a type of artificial insemination where sperm is placed near or at the cervical opening instead of the uterus. ICI closely mimics the natural process of insemination.

(4) Gamete Intrafallopian Transfer (GIFT)

In a gamete intrafallopian transfer, the sperm and ovum are retrieved from the male and female partners. Both gametes are then released in the fallopian tube, where they will first develop into an embryo and then move into the uterus. GIFT mimics the process of natural conception.

Advantages Of In Vivo Fertilization

(1) In vivo fertilization uses the natural process of conception
(2) Embryos have a higher survival rate in vivo due to the supportive environment inside the body.
(3) A single egg may be enough to create an embryo and successfully induce pregnancy.

Disadvantages Of In Vivo Fertilization:

(1) In vivo fertilization cannot be used to treat serious infertility issues or conditions
(2) The quality and health of the resulting embryos cannot be tested, which can put it at risk of developing genetic conditions
(3) Those using in vivo fertilization may take a longer time to get pregnant than those using in vitro techniques

What Does In Vitro Mean?

In vitro is Latin for ‘within the glass’. In vitro is used to refer to something that happens outside of a living creature.

In in vitro fertilization, the egg and sperm are first retrieved from the body and then combined in laboratory conditions to form an embryo outside of it. So, the actual process of fertilizing the egg with sperm takes place in a laboratory and not inside the human body.

The procedure begins with the woman receiving fertility medications to regulate her ovulation and stimulate her ovaries to produce more eggs. In IVF, it is believed that a higher number of eggs means more chances at success.

The mature eggs are then retrieved from the woman’s ovaries, while the man provides the clinic with a semen sample. Occasionally, the patient may supply one gamete and use an egg or sperm donor for the other.

The developed embryo is then carefully placed back in the woman’s uterus, where it will eventually implant and grow into a fetus.

Types of In Vitro Fertilisation

Conventional in vitro fertilization, or IVF, is the most popular type of fertility treatment. Here are some other types of IVF procedures offered:

(1) Intracytoplasmic Sperm Injection (ICSI)

ICSI is a variation of IVF treatment. It involves directly injecting a high-quality sperm into a mature egg to kickstart the process of fertilization. ICSI is usually recommended in case of severe male factor infertility.

(2) Natural Cycle IVF

Natural cycle IVF is when the patient undergoes the IVF process without ovarian stimulation or use of other fertility drugs. It is used on patients who want to limit the amount of medication they take or for women who are exceptionally sensitive to hormonal medication.

(3) Mini IVF

Mini IVF is similar to IVF. It involves using a lower dose or milder fertility drugs during ovarian stimulation. This results in fewer eggs than conventional IVF, but also causes fewer side effects.

(4) Frozen Embryo Transfer (FET):

In an FET, previously frozen embryos from a past IVF cycle or from donor sources are thawed and transferred into the uterus. This helps women have multiple chances of pregnancy without going through the entire IVF process again.

(5) IVF with Donor Eggs/Sperm:

When either the woman or man has fertility issues, donor eggs or sperm can be used in the IVF process.

(6) Zygote Intrafallopian Transfer (ZIFT)

ZIFT is a process in which the egg and sperm are fertilized in a lab and the resulting zygote (day 3 embryo) is transferred to the woman’s fallopian tube. This allows it to keep growing and develop into a blastocyst before reaching the uterus.

Advantages Of In Vivo Fertilization

(1) IVF allows for genetic screening of embryos before implantation, which can help identify and avoid embryos with certain genetic abnormalities.
(2) It can reduce the risk of miscarriage by handling many of the processes of fertilization outside the body
(3) IVF testing can help people with infertility issues conceive, even those with a high parental age or conditions like PCOS
(4) IVF has a higher success rate than many other fertility treatments
(5) It allows couples to use donor eggs or sperm if they have issues with their own.
(6) It allows you to preserve embryos for later use

Disadvantages of In Vitro Fertilization

(1) IVF requires a mix of surgical procedures and medication, both of which can have side effects on the body
(2) IVF requires multiple eggs and healthy sperm due to the lower survival odds of embryos in vitro
(3) It can take a long time, anywhere from 4-6 weeks to a year, depending on individual circumstances
(4) It is more expensive than in vivo techniques
(5) IVF can put significant financial and emotional strain on the patient

In Vivo vs. In Vitro Fertilization: Key Differences Explained

Now that we’ve looked at their meaning, types, and advantages, let’s explore the difference between in vivo and in vitro fertilization.

Conclusion

In vivo fertilization follows the natural and biological process of fertilization and in vitro fertilization allows people who have infertility issues to have a child of their own.

While in vivo fertilization may seem more tempting due to its natural and less invasive approach, it is not the recommended treatment for patients with severe infertility issues. Instead, IVF can offer greater flexibility and a higher chance of success.

Both in vivo vs. in vitro fertilization offer different advantages depending on your fertility challenges, age, and goals. Speak to an experienced fertility specialist at Corion Fertility Clinic for guidance on which types of fertilization and fertility treatment are the best for you.

Frequently Asked Questions:

Q. Is ICSI performed in in vivo fertilization?
A. No, ICSI is a type of in vitro fertilization. In this procedure, a single sperm is injected directly into an egg in a laboratory setting, not inside the body.

Q. Is artificial insemination considered in vivo fertilization?
A. Yes. Artificial insemination includes IUI and ICI treatments, and it is classified as an in vivo technique because fertilization occurs inside the body.

Q. Which is more successful, in vivo or in vitro?
A. IVF tends to have a higher success rate because it allows for closer monitoring and genetic screening. It also helps bypass a lot of infertility issues by completing fertilization outside the body.

Q. Can you switch from in vivo to in vitro if one doesn’t work?
A. Yes, you can. In fact, most fertility journeys begin with less invasive methods like IUI and only move on to IVF if it is necessary.