How Much Time Sperm Take to Reach Egg

Fertilisation of an egg is the beginning of a new life. To make the fertilisation possible a healthy sperm and egg are essential. If you are planning to build a family, learning about the different stages of fertilisation and finding out about the time taken for sperm to reach egg can be helpful. Let’s start off with some basic facts about fertilisation.

Each month, women undergo the process of Ovulation. If a sperm fertilises the egg released during ovulation, it will result in the formation of an embryo that will eventually get implanted on to the lining of the uterus and develop into a baby. After ejaculation, the sperms enter the female reproductive system where they compete for their chance to fertilise the egg.

The answer to how does sperm work inside women is both simple and complex. The main goal of a sperm is to fertilise an egg, for which every sperm goes up inside a woman through her cervix and passes the uterus to reach the egg, which is most likely somewhere in a fallopian tube. However, the journey is not as simple as it sounds.

Here, you will learn about how long does sperm take to reach the egg and more interesting details about the sperm and egg fertilisation process.

How Long Does It Take Sperm to Reach the Cervix?

A healthy sperm can cover the distance from the upper vagina to the cervix in about a few minutes if it has good motility.

To protect bacterial infections, the upper vaginal area is usually quite acidic, ranging about 4.3 pH. Within approx 10 seconds after the semen has entered the vagina, this pH raises to as much as 7.2 which is quite similar to the pH levels of the semen. However, this buffering effects lasts only a few minutes before the vaginal fluid closer to the cervix becomes acidic again. During this buffering period the sperm has to approach the cervix; the optimal environment for sperm motility is between pH 6.0 and pH 6.5.

Journey of a Sperm: After Reaching the Cervix

Upon reaching the cervix, the spermatozoa or sperms must overcome the next barrier—the cervical mucus and the cervical canal. The cervical mucus blocks the entry of pathogens into the uterus to prevent any infections. Generally, intravaginal pressure may help the spermatozoa propel into the uterus, but they may also have to swim upwards to facilitate their transport into the uterine cavity.

The thickness and composition of the cervical mucus keeps changing throughout the menstrual cycle of a woman. From the 9th day of the menstrual cycle up to the 16th day (the ovulation period), the cervical mucus is relatively easier to penetrate as its water content increases during the ovulation period. The cervical mucus thickens after the ovulation window making it almost impossible for sperm to pass through.

Spermatozoa can travel through the cervix into the uterine cavity within 5-20 minutes of ejaculation due to the muscular movements of the female reproductive tract. However, such sperm are not as effective in fertilising the egg as those sperm who have spent more time in reaching the egg from the upper vagina. The second mode of transportation for the sperm involves the swimming of spermatozoa through the cervical mucus at the rate of 2-3 mm every hour. These sperms also get stored in the crevices inside the cervix before moving up the uterine cavity out of the cervical canal, which can take up to 2-4 days in total.

Although there is little research on how the spermatozoa moves through the uterus, but their transportation is attributed to the contraction of the smooth muscle of the uterus more than the sperm motility.

Journey of a Sperm: After Reaching the Fallopian Tube

Upon reaching the fallopian tube, the spermatozoa collect in the isthmus, which is the part of the fallopian tube that is closest to the uterus, and they bind to the epithelium for about 24 hours. During these 24 hours, the spermatozoa undergo a capacitation reaction. Afterwards, some of the spermatozoa detach from the epithelium after a period of hyperactivity and move further along the fallopian tube by penetrating the isthmic mucus and the protective layers of the ovulated egg. At a given moment, only a small number of the spermatozoa are released from the epithelium.

How Many Sperm Reach the Egg, and Where Does Fertilisation Take Place?

Very few sperm, only a few hundred out of 40-250 million released during ejaculation, reach the fallopian tubes due to the numerous natural barriers present inside a woman’s reproductive tract.

During the ascent of the spermatozoa after capacitation is completed, the egg is also travelling towards the uterus in the fallopian tube. It can take 1-2 days for the spermatozoa to meet with the egg inside the fallopian tube. The fertilisation of the egg normally occurs inside the upper third part of the fallopian tube (also known as ampulla).

Did you know that a sperm can live inside a woman’s reproductive tract and maintain its reproductive function up to 80 hours?

What Happens During Fertilization?

As soon as a viable sperm comes in contact with the outer layer of the egg, the sperm cell undergoes rapid changes. This leads to the breaking down of the vitelline coat of the egg and facilitates the sperm’s passage through the egg. The integrity of the egg’s protective membrane is restored soon after the sperm reaches the interior of the egg to prevent the fusion of more than 1 sperm with the egg.

Afterwards, the egg cortical reaction creates a fertilisation membrane around the fertilised egg, which is a permanent block for preventing any other sperm to penetrate the egg. The nucleons of the sperm swell after fusing with the egg cytoplasm and the chromosomal material is dispersed inside the egg evenly and starts resembling the female pronucleus. This leads to the formation of a single called embryo, which is called a zygote. The genetic makeup of the baby is complete at the moment of fertilisation.

The fertilisation procedure is the same in case of in vitro fertilisation (IVF) as well; the only difference is that fertilisation occurs in an embryology lab and the sperm fertilising the egg does not have to swim through the female reproductive tract to reach the egg.

What Happens After Fertilisation?

After fertilisation, the zygote undergoes rapid division into numerous small cells and becomes an organised mass, also known as a blastocyst. When the embryo starts to divide rapidly, it starts moving towards the uterus to implant itself in the endometrium. It can take about 3-4 days for the embryo to enter the uterus.

In case of IVF fertilisation, the embryo is incubated under the right condition to support the rapid division of cells and about 5-6 days after fertilisation, a viable embryo is transferred to the uterus for implantation.

The Odds of Getting Pregnant

Research suggests that woman who are aged 30 years or younger have about 20% chances of getting pregnant in a menstrual cycle. This percentage drops to a whopping less than 5% by the time a woman turns 40. As per the physical requirements of the body, 20-25 is the best age to get pregnant. However, many people are not ready to raise a child at that age. Thus, assisted reproductive technologies (ARTs) like IVF can be extremely helpful in such cases.

Can You Improve Your Chances of Getting Pregnant?

Yes. You may be able to improve your conception naturally by tweaking your lifestyle just a little bit and tracking the menstrual cycle of your partner. Having unprotected sexual intercourse when you are ovulating gives you a higher chance of pregnancy than before or after the ovulation window. Additionally, poor diet, excessive use of alcohol, smoking, etc. can negatively impact your fertility.

Things to Do to Boost the Chances of a Sperm Fertilising the Egg

Here are some things that you can try to boost your chances of conception:

• Exercise regularly in moderation
• Consume a balanced meal
• Ensure optimum sleep
• Quit smoking at least 3 months before you plan on engaging in sexual intercourse
• Avoid excessive alcohol consumption

In the End

If you are thinking of building a family, you may find yourself wondering about how fertilisation process works and how much time does sperm takes to fertilise egg. Well, it is natural to wonder about such things. Talking to a fertility expert can help you understand the intricacies of the reproduction process and the importance of each stage in it.

Hopefully, the above-mentioned information has helped you in clarifying your doubts. If you still have any questions about the time for sperm to reach egg or any other aspect of conception, consult with our fertility experts near you.

FAQs

Q. What is the time taken for sperm to reach egg?

A. It can take anywhere from 1 to 5 days for a sperm to reach an egg before it is ready for fertilisation.

Q. What is the importance of sperm and egg fertilisation process?

A. Sperm contrains half the genetic makeup of a baby, without which it is impossible to fertilise an egg and conceive a child. Both these cells play an important role in reproduction. The sperm and egg are destined to die shortly after their release if the sperm doesn’t fertilise the egg.

Q. Where does fertilisation takes place?

A. Fertilisation of an egg occurs inside the fallopian tube of the intended mother in case of natural conception. If the couple is opting for IVF, fertilisation occurs outside the mother’s body in an embryology lab.