Conception

Conception (also called fertilization) is when an egg and sperm join. It’s a key step in getting pregnant. The fertilization process begins with ovulation and ends when a fertilized egg implants in your uterus.

Ovulation

Ovulation is when your ovary releases an egg. It happens around the middle of your menstrual cycle. Tiny finger-like structures help guide the egg through your fallopian tubes toward your uterus. During this journey through your fallopian tubes, an egg can be fertilized by sperm.

Sperm release and travel

During ejaculation, millions of sperm cells are set free with the sole purpose of finding an egg to fertilize. Sperm swim up through your vagina and into your fallopian tubes. Millions of sperm battle to reach and penetrate the egg. But only one breaks through the egg’s outer layer to fertilize it.

Fertilization

When a sperm enters the egg, the genetic material in both combine to form a single cell. This is called a zygote. If sperm doesn’t fertilize an egg, the egg dissolves.

Blastocyte formation

The zygote continues to move down your fallopian tube, dividing into two cells, then four cells, then more cells. About a week after the sperm has fertilized the egg, the zygote has traveled to your uterus. It’s now a growing cluster of about 100 cells called a blastocyst.

Implantation

The blastocyst attaches itself to your uterine lining. This attachment process is called implantation. If implantation doesn’t happen, the blastocyst dissolves.

If implantation happens, the cells continue to divide — some cells develop into a fetus and others form the placenta. You begin to release hormones that tell your body a pregnancy is happening. These hormones stop you from getting your period. This is usually the first way you know you’re pregnant.

Where does conception and fertilization happen?

Conception typically happens in your fallopian tubes. This is where an egg goes after it leaves your ovary and where sperm waits for an egg. Sometimes, fertilization can happen in your uterus.

How long does fertilization take?

Sperm can penetrate an egg and “fertilize” it within a few minutes. But the full fertilization process (when the genetic material from the sperm and egg combine) can take several hours.

When does conception happen?

Conception can occur between 12 and 24 hours after ovulation. It’s sometimes hard to pinpoint ovulation, so using ovulation predictor kits or tracking your menstrual cycle may be helpful.

How long does it take to conceive?

There are many things that affect how long it takes to conceive. Age, how often you have sex and if you ovulate regularly all play a role. If you’re trying to conceive and it hasn’t happened, despite having sex regularly, it’s a good idea to talk to a healthcare provider. They may be able to recommend ways to increase your chances.

What are my chances of conceiving?

Just because an egg and sperm are near each other doesn’t mean conception will happen. In general, conception only occurs about 1 in 4 times. This percentage decreases once you reach age 35. There are many other factors that can affect your chances of conception.

What things prevent conception from happening?

Certain health conditions may affect your ability to conceive. Just because the sperm and egg meet doesn’t mean fertilization will occur. Some of the more common reasons conception isn’t happening are:

• Not ovulating regularly
• Not having sex during your fertile window
• Low sperm count or issues with how sperm move
• A blockage in the testicles, ovaries or fallopian tubes
• Issues with sperm or egg health
• Hormonal issues

Can you feel conception?

Not usually. You may notice signs of ovulation, like changes in your vaginal discharge. But most people don’t feel fertilization. You may feel a dull ache or have light bleeding several days after conception (implantation bleeding).

What are the different types of fertilization?

Fertilization can happen naturally or with medical help:

• Natural fertilization: This happens inside your body after sex, when sperm swims up and fertilizes an egg.
• Assisted fertilization: This type happens in your body but requires some medical intervention. Your provider places sperm directly into your uterus to help with fertilization. This is called intrauterine insemination (IUI).
• Artificial fertilization: This type happens during fertility treatments, like IVF (in vitro fertilization) or ICSI (intracytoplasmic sperm injection). It’s when fertilization happens outside of your body in a lab.

Is the conception date the day I got pregnant?

Yes, but knowing the exact date is hard to determine during natural fertilization. Because of this uncertainty, healthcare providers calculate your due date based on your last menstrual period (if you become pregnant). But if you conceive using IVF, your providers know the exact date of conception.