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What Is Conception? Understanding the First Step Toward Pregnancy

Reviewed by Dr. Manisha Acharya ,

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Last updated: August 25, 2025

Introduction

When two cells, that is, an egg from a female and a sperm from a male, meet in the fallopian tube, it marks the first step of pregnancy, called conception. What signs does it give off? Is conception affected by anything? These are the questions anyone planning for a baby has, which are legit too, as understanding conception offers clarity and awareness. If you, too, have these questions, then go no further because this blog brings everything you need to understand about this process. So, let’s begin!

What Is Conception?

Conception is the moment when an egg meets a sperm. The sperm penetrates the egg, resulting in fertilisation. This marks the beginning of human life, when these two cells combine to create something new — a zygote.

The zygote is a single cell which carries the genetic makeup of an individual, required to fully grow into a baby. This single cell, after its successful implantation in the uterus, begins to develop step by step.

How Conception Happens Naturally

The conception process may sound like a simple biological phenomenon, but it requires a series of complex procedures, beginning with the menstrual cycle of a woman:

Ovulation: Ovulation is the release of a mature egg into the fallopian tube from one of the two ovaries. This usually occurs exactly 14 days before the first day of your period. However, the released egg remains viable for about 12 to 24 hours after ovulation. Hence, timely intercourse around the time of ovulation is a necessity for a successful conception.
Fertilisation: Fertilisation is the actual point of conception. Normally, it occurs in the fallopian tube when a sperm enters via the cervix and travels across the uterus to meet the egg there. In general, out of millions of sperm, only one becomes successful in fertilising the egg.
Cell Division and Travel: After fertilisation, the zygote undergoes specialised cell division to form a cluster of cells, also known as a blastocyst and continues to move down the fallopian tube. It takes a blastocyst almost 3 to 5 days to travel to the uterus from the fallopian tube. During these days, the uterus prepares itself to receive the fertilised egg for implantation.
Implantation: Once the fertilised egg reaches the uterus, implantation happens. At this phase, the egg continues to divide further to develop into the baby and a placenta. The implantation also signals your body to release hormones required for the proper development of your baby. Note that without implantation, even a fertilised egg won’t result in a pregnancy. This means that conception is considered the first step of pregnancy, but it doesn’t always guarantee a successful pregnancy.

Signs and Symptoms of Conception (May Vary):

A successful conception typically results in some early signs and symptoms, although these may vary from person to person or may not appear at all in some individuals. These early signs and symptoms include:

Light spotting (known as implantation bleeding)
Mild cramping, similar to menstrual cramps
Breast tenderness or slight swelling
Fatigue or sleepiness
Changes in mood or emotional sensitivity

The above-mentioned symptoms also resemble the signs of PMS, so they are not definitive proof of pregnancy.

Conception Through Assisted Reproductive Techniques (ART):

Facing fertility challenges? Assisted reproductive techniques are here to help! Those facing challenges in conceiving can get help from techniques, such as IVF or IUI. This is how these processes work:

Technique	How it Works
IVF (In Vitro Fertilisation)	In this, eggs and sperm are fertilised in a laboratory setting to form embryos. One or more of these embryos are then transferred to the uterus for implantation. IVF skips the cell travel from the fallopian tube to the uterus to initiate a successful pregnancy.
IUI (Intrauterine Insemination)	IUI involves sperm collection from the male and their insertion directly into the uterus during the ovulation phase. Fertilisation in this technique occurs naturally inside the body, followed by implantation.

Though the methods differ, the core process after fertilisation—cell division, embryo travel, and implantation—remains the same.

Factors That Affect Conception:

Conception is not always guaranteed in a cycle — it is affected by several internal and external factors. These factors influence how conception happens, and when it leads to pregnancy and when it does not. These factors include:

1. Egg and Sperm Quality:

Poor quality of sperm or eggs leads to either unsuccessful fertilisation or non-viable embryos if fertilisation does occur.

2. Timing of Intercourse:

Conception is not something that can occur at any phase of the menstrual cycle. Intercourse close to the date of ovulation is the key to successful conception and eventually pregnancy, if everything goes right.

3. Hormonal Balance:

Any change in fertility hormones like estrogen, LH, and progesterone can lead to an increased or decreased chance of conception. Therefore, regulation of these hormones is necessary.

5. Lifestyle:

Smoking, drinking, or poor nutrition does not help in conception; rather, it can increase the chances of failed pregnancies. It can also impact the conception process.

6. Medical/Health Conditions:

Medical conditions like PCOS, thyroid disorder, or endometriosis are a big hindrance to ovulation and, eventually, unsuccessful conception.

When Does Conception Lead to Pregnancy? :

It must be noted that conception doesn’t always lead to pregnancy. Once the embryo implants into the uterine lining, only then, the pregnancy officially begins. If it does, the pregnancy test is usually done after 10 to 14 days, in which the levels of hCG (human chorionic gonadotropin) hormones are checked. This hormone is produced only after a successful implantation.

So, where does the fertilised egg go if not implanted inside the uterus? It is either absorbed by the body itself or released during periods.

Conclusion

So, what is conception? Simply put, it is the first step of pregnancy — the time when conception occurs by the combination of egg and sperm. Ovulation, fertilisation, and implantation in the uterus are all part of the process. Knowing how conception occurs empowers individuals to be aware of their reproductive process with discernment, confidence, and a better purpose.