Updated on December 28, 2022

I want to know the correct answer!
Best timing for intercourse when trying to conceive

  • Timing of sexual intercourse
  • Lifespan of sperm and eggs
  • ovulation day

Clock illustrationReading time: 4 minutes 30 seconds

Want to know the correct timing for intercourse for conception?

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Dr. Masayuki Kinutani, Director of Kinutani Obstetrics and Gynecology Clinic

Dr. Masayuki Kinutani, Director of Kinutani Obstetrics and Gynecology Clinic

Supervision

Director, Kinutani Obstetrics and Gynecology Clinic (Medical Corporation)
​Mr. Masayuki Kinutani

After graduating from Ehime University School of Medicine, she worked at the Department of Obstetrics and Gynecology at Hiroshima University School of Medicine and the Sanno Hospital Reproduction Center, before studying advanced reproductive technology in Canada, the United States, and the United Kingdom. In 2002, she became the director of Kinutani Obstetrics and Gynecology Clinic. She is a certified obstetrician and gynecologist by the Japan Society of Obstetrics and Gynecology and a certified reproductive medicine specialist by the Japan Society for Reproductive Medicine.

What is the best timing for sexual intercourse to increase the chances of conception?

Illustration of a woman who is troubled.

Last time, I learned that the timing of intercourse is important for increasing the chances of conception. Could you please explain in more detail?

Mr. Masayuki Kinutani

Regarding the timing of sexual intercourse, as the first step in infertility treatment, clinics also provide "timing guidance" to instruct patients on the best time to have intercourse to increase the chances of conception.

First, you should know the lifespan of both ejaculated sperm and ovulated eggs.
It is generally said that ejaculated sperm can survive for up to 5 days, and on average, about 3 days.
On the other hand, the period during which an egg can be fertilized is only about 12 to 24 hours after ovulation. Since eggs have a shorter lifespan, it is best to have intercourse before ovulation so that sperm can wait in the fallopian tubes for the egg to arrive.

Furthermore, the amount of cervical mucus, which helps sperm enter the uterus, peaks 2-3 days before ovulation, so it is said that the period with the highest chance of conception is "from 2-3 days before ovulation to the day of ovulation."
However, considering the lifespan of sperm, keep in mind that there is still a good chance of conception even 4-5 days before ovulation.

A graph to help you understand the timing of sexual intercourse.

Knowing your ovulation day correctly is key.

Illustration of a woman who is troubled.

I see! So, knowing the correct timing of ovulation is important!

Mr. Masayuki Kinutani

That's right. There are several ways to predict your ovulation day yourself, so please refer to this article as well.

Essential Knowledge about Ovulation Day ② How to Calculate Ovulation Day

To predict ovulation more accurately, medical institutions also use ultrasound to observe the follicles. Follicles in the ovaries gradually grow larger from around the end of menstruation, and although there are individual differences, ovulation occurs when the follicle reaches a diameter of about 20 mm. Therefore, it is possible to predict the ovulation day by measuring the size of the follicle with ultrasound.

The window for the best timing is surprisingly wide.

Illustration of a woman who is troubled.

I understand the best timing to increase the chances of getting pregnant, but I'm worried about whether I can coordinate my schedule with my partner...

Mr. Masayuki Kinutani

We often receive such inquiries from patients. While the theoretically most likely time for conception is "two to three days before ovulation," there's no need to insist on having intercourse on that specific day.

Try to think positively about the fact that sperm can live for up to 5 days. There is still a good chance of conception even if you time intercourse 4-5 days before ovulation, so instead of worrying about timing it perfectly, why not think that it's okay if you have intercourse at least once before ovulation?
Also, if you have multiple opportunities to try, having intercourse every other day for 2-3 times starting 4-5 days after your period ends, until ovulation is over, will allow the sperm to be fresher and increase the chances of conception compared to trying to conceive only once.

Illustration of a woman who is troubled.

I see, that would make it easier to approach trying to conceive.
However, if fertilization did occur, would intercourse after fertilization have any effect on implantation?

Mr. Masayuki Kinutani

From a medical standpoint and based on my clinical experience, I don't believe that intercourse after fertilization interferes with implantation. There's no need to think you need to rest because you've ovulated; it's better to continue your normal daily life.
Stress is bad for pregnancy, so try not to worry too much about anything. I've seen many women who conceived when they thought, "The timing wasn't right this cycle, so I'd given up."

Illustration of a woman

Finally, do you have a message for the women who have read this article?

Mr. Masayuki Kinutani

The timing of intercourse is important for conception, but I hope you now understand that there is actually quite a bit of flexibility in that regard. Ovulation only occurs once a month, so it's easy to feel anxious about missing each opportunity, but ideally, you should start trying to conceive before you feel that anxious.
Therefore, even if you feel that now isn't the right time to have children, I would like you to learn about pregnancy as early as possible, especially the fact that it becomes more difficult to conceive with age.

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