โอกาสตั้งครรภ์ในแต่ละเดือนที่แท้จริงเป็นเท่าไร?

อัปเดตล่าสุด: สิงหาคม 25, 2026

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Men ask this constantly, usually after a few months of trying: how likely is this each month, and are we doing something wrong? The earlier version of this article discussed timing at length but never actually answered the question in its own title. Here is the answer first.

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The number most couples are never told

For a healthy couple in their twenties or early thirties having regular intercourse, the chance of conceiving in any one cycle is roughly one in four. Not one in two, and nowhere near certain.

Cumulatively that works out at around 85 out of 100 couples conceiving within a year, and a further portion of the remainder during the second year. Which means that three or four months without success is entirely ordinary and says nothing about either partner.

These figures fall with age, and female age is the single strongest influence — considerably stronger than anything about timing, position or technique. Male fertility declines too, more gradually and from a later age.

Pregnancy rate is not live birth rate

The figures above describe achieving a positive pregnancy test. Not every pregnancy continues: early loss is common, and often happens before a period is even noticed as late. The chance of a live birth in any given cycle is therefore lower than the chance of conception, and this too is strongly influenced by age.

An earlier version of this article referred to pregnancy as lasting ten months; it is about forty weeks, or nine months.

Timing: the fertile window, and why not to aim at one day

Conception is possible during a window of roughly six days ending on the day of ovulation. Sperm survive several days in receptive cervical mucus; an egg does not. That asymmetry explains the two facts worth remembering:

• The best days are the two or three ก่อน ovulation, when sperm are already waiting when the egg is released.
• After ovulation the chance falls to near zero within about a day. Intercourse later in the cycle will not achieve anything, which is the one piece of timing advice that genuinely changes outcomes.

A correction, and better practical advice

The earlier version gave precise percentages for single days — over 40% one day before ovulation, over 30% two days before — drawn from studies of couples already proven fertile, and presented them as though a couple should aim at one particular day. Two problems with that.

First, those figures come from couples who had already had a child, so they are optimistic for the general population. Second, and more practically: aiming at a single calculated day usually lowers a couple’s chances rather than raising them. Ovulation is not reliably predictable in advance, cycles vary, and a day missed by two either way is a cycle wasted. It also turns sex into an appointment, which couples find corrosive and which is itself a common reason for reduced frequency.

The better approach is simpler: intercourse every two or three days throughout the cycle, or every one to two days across the week leading up to expected ovulation. That covers the window without requiring anyone to predict it, and it does not depend on kits, charts or arithmetic. Abstaining to save up for the right day does not help — it lowers sperm motility rather than improving the odds.

What actually helps, and what does not

Worth doing

• Check the lubricant. Most ordinary lubricants — and saliva — impair sperm movement. If one is needed, use a product specifically labelled fertility-friendly. This is a real and easily fixed problem.
• Do not douche. It disturbs the vaginal environment and the cervical mucus that sperm depend on.
• Stop smoking, both partners. It affects egg and sperm quality and is among the few genuinely modifiable factors.
• Address weight, alcohol and recreational drug use. Anabolic steroids in particular shut down sperm production, sometimes for a long time after stopping.
• Limit regular heat exposure — habitual hot tubs, saunas, and a laptop resting on the lap. The effect is on sperm production over months, not on any single occasion.

Two things this article previously recommended that have been removed

• Raising the woman’s hips after ejaculation. This was given here with a specific measurement, and there is no good evidence for it. Sperm reach the cervical mucus within minutes and are not moved there by gravity; lying still afterwards for comfort is fine, but it is not a fertility technique and no one should feel they have failed by getting up.
• Avoiding a hot bath immediately before sex. The reasoning was wrong. Heat affects sperm as they are produced, over roughly three months — a bath beforehand does not damage the sperm being ejaculated that evening. Regular heat exposure matters; the timing of one bath does not.

Genuinely irrelevant

Sexual position makes no difference, and neither does whether the woman has an orgasm. Both come up often enough in clinic to be worth stating plainly.

When trying longer stops being the right plan

This was absent from the earlier version and is the most useful thing on the page. Seek assessment — both partners together — when:

• Twelve months of regular unprotected intercourse have passed without conception.
• Six months, if the female partner is over about 35. Waiting the full year in this situation costs time that matters.
• Straight away, at any duration, if there is a known reason to expect difficulty — irregular or absent periods, previous pelvic surgery or infection, an undescended testis in childhood, previous testicular surgery or injury, chemotherapy or radiotherapy, anabolic steroid use, or a known genetic condition.

Assessment of the man is straightforward and begins with a การตรวจวิเคราะห์น้ำอสุจิ, which is worth reading about beforehand because the numbers are so widely misread. If testosterone treatment has been suggested to you, read what it does to fertility first — testosterone given from outside the body suppresses sperm production, and there are alternatives that do not.

Symptoms that need attention regardless of fertility plans

กรณีฉุกเฉินในประเทศไทย โปรดโทร 1669.

• A lump in a testis — testicular cancer is commonest at exactly this age.
• Sudden severe testicular pain, which needs attention the same day.
• Blood in the semen, or pain on ejaculation.
• In the female partner: severe pelvic pain, or a positive pregnancy test with pain or bleeding, which needs same-day assessment.

คำถามที่พบบ่อย

What is the chance of conceiving in one cycle?

Roughly one in four for a healthy couple in their twenties or early thirties having regular intercourse, with around 85 in 100 conceiving within a year. The figures decline with age, female age most of all.

When in the cycle should we have sex?

The fertile window is about six days ending on the day of ovulation, and the best days are the two or three before it. Rather than trying to hit one day, have intercourse every two to three days through the cycle — that covers the window without requiring anyone to predict ovulation, and single-day targeting usually lowers the overall chance.

Should we save up sperm for the fertile days?

No. Prolonged abstinence increases volume but worsens sperm motility, and it risks missing the window entirely. Regular intercourse is better than saving up for a calculated day.

Does raising the hips after sex help?

There is no good evidence that it does, and an earlier version of this article recommended it with a specific measurement — that recommendation has been withdrawn. Sperm reach the cervical mucus within minutes rather than being carried there by gravity.

Does the lubricant we use matter?

Yes, and this is one of the few things easily fixed. Most ordinary lubricants, and saliva, impair sperm movement. Use a product specifically labelled fertility-friendly, or none at all.

How long should we try before seeking help?

Twelve months, or six if the female partner is over about 35, or straight away if there is a known reason to expect difficulty. Both partners should be assessed together — investigating only one of them wastes time.

การนัดหมายเพื่อปรึกษาแพทย์

Dr. Soarawee Weerasopone sees male fertility and andrology patients at โรงพยาบาลกรุงเทพ สำนักงานใหญ่ และที่ Samitivej Sriracha Hospital จังหวัดชลบุรี ในวัน 088-022-1445. Bring any previous semen analysis reports and any results your partner already has.

บริการ Bangkok Hospital Telemedicine พร้อมให้บริการสำหรับผู้ป่วยที่ไม่สามารถมาพบแพทย์ด้วยตนเองได้ รวมถึงผู้ป่วยชาวต่างชาติ — กรุณานัดหมายล่วงหน้าทางอีเมลถึงแผนกศัลยกรรมระบบทางเดินปัสสาวะที่ bhquro@bdms.co.thโรงพยาบาลสมิติเวช ศรีราชา ให้บริการเฉพาะการพบแพทย์ที่โรงพยาบาลเท่านั้น สำหรับข้อสอบถามเรื่องค่าใช้จ่าย ทางโรงพยาบาลจะเป็นผู้ตอบ ไม่ใช่เว็บไซต์นี้

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