FERTILITY EDUCATION

Understand your fertility

A clear, doctor-written guide to how conception works, what affects it and what the tests and treatments actually involve. It draws on M.R. Dr. Tongtis Tongyai’s 40+ years as an OB-GYN — since 1983 — and his work founding the Blastocyst Center at Praram 9 Hospital in 1998.

Written by
Dr. Tongtis Tongyai
OB-GYN since
1983
Reading time
About 12 minutes
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M.R. Dr. Tongtis Tongyai, OB-GYN and fertility specialist

Learn library

Plain-language guides to fertility, health and our procedures — each one sourced from international medical guidance.

Getting ready

Genetic carrier screening and thalassemiaMany Thais carry thalassemia without knowing. A simple couple blood test before pregnancy helps you plan. 3 · Read →Preconception health checklistA tickable list of check-ups, tests and vaccines for both partners before you try for a baby. 4 · Read →

Understanding fertility

Female fertility and ageEggs decline in number and quality with age. What AMH really tells you and when to act. 3 · Read →How to get pregnant naturallyYour cycle, your fertile window and simple timing tips, plus a fertile-window calculator. 3 · Read →Male fertility and sperm healthSperm health matters as much as egg health. What a semen analysis shows and what helps. 3 · Read →

Conditions

Endometriosis and fertilityPainful periods are not something to just put up with. Learn about endometriosis and fertility. 3 · Read →PCOS and fertilityPCOS is common and treatable. Learn the signs, how it is diagnosed and the options for conceiving. 4 · Read →Thyroid, diabetes, weight and blood pressureThyroid, diabetes, weight and blood pressure: why getting them checked first helps you and your baby. 3 · Read →

Health & lifestyle

Lifestyle and fertilitySmoking, alcohol, caffeine, sleep and stress: everyday habits that matter for both partners. 4 · Read →Nutrition and supplements before pregnancyFolic acid, vitamin D, iodine, iron, fish and a balanced plate: what to do before you conceive. 4 · Read →Sexual health, STIs and fertilitySome STIs are silent but can harm fertility. Testing and treatment are simple and confidential. 3 · Read →

Support

Early pregnancy and miscarriageEarly pregnancy care, warning signs that need urgent help, and kind, factual miscarriage information. 4 · Read →Emotional health while trying to conceiveFertility stress is common and valid. Gentle ways to cope, and when to ask for extra support. 3 · Read →Questions to ask your fertility doctorA printable list of what to bring and what to ask at your first fertility consultation. 4 · Read →

How our procedures work

How AMH testing worksA simple blood test that estimates your egg supply, and the limits you should know. 3 · Read →How blastocyst culture worksWhat happens to embryos in the lab from day 1 to day 5, and why day 5 matters. 3 · Read →How egg and embryo freezing worksFrom hormone injections to liquid nitrogen: how eggs and embryos are frozen and later warmed. 3 · Read →How embryo transfer worksA short, usually painless step: how an embryo is placed in the uterus and what comes next. 3 · Read →How GIFT worksEggs and sperm placed in the fallopian tube: how GIFT works and why it is now uncommon. 3 · Read →How a tube test (HSG) worksA short X-ray test that shows whether the tubes are open. What happens and what it feels like. 3 · Read →How hysteroscopy worksNo cuts on the skin: a thin camera looks inside the womb and can remove polyps or scar tissue. 3 · Read →How ICSI worksICSI injects one sperm into each egg to help fertilisation when sperm need extra help. 4 · Read →How IUI worksWashed sperm placed in the womb at the right time: how IUI works and who it suits. 3 · Read →How IVF worksWhat happens in an IVF cycle, step by step, and what each stage feels like. 4 · Read →How laparoscopy worksKeyhole surgery that can find and treat endometriosis, cysts, scar tissue and tube problems. 4 · Read →How PGT worksHow a few cells from an embryo are tested, what the results mean and their limits. 3 · Read →How semen analysis worksA simple, painless test that checks sperm count, movement and shape. What to expect and how to read it. 4 · Read →How ultrasound and follicle tracking workHow scans count follicles, track egg growth and check the womb during fertility care. 4 · Read →

How conception works

Getting pregnant depends on several steps happening in the right order, at the right time. Knowing them makes it easier to understand where things can go wrong — and what each test or treatment is trying to help.

  1. OvulationUsually once per cycle, an ovary releases a mature egg. The egg can only be fertilised for roughly a day after it is released.
  2. FertilisationSperm travel through the uterus to the fallopian tube, where one sperm may fertilise the egg. Sperm can survive in the body for up to about five days.
  3. Embryo to blastocystThe fertilised egg divides as it moves down the tube. By around day 5 it becomes a blastocyst — the same stage our lab grows embryos to before transfer.
  4. ImplantationThe blastocyst attaches to the lining of the uterus, usually about a week after ovulation. A home pregnancy test is usually reliable from around the day your period is due.
Read more about blastocyst culture →

Fertility and age

Age is the single most important factor in female fertility. A woman is born with all the eggs she will ever have; both the number and the quality of those eggs fall over time.

Egg quantityThe supply of eggs (ovarian reserve) declines steadily, and the decline becomes more noticeable from the mid-30s.
Egg qualityWith age, a higher share of eggs carry chromosomal errors. This lowers the chance of pregnancy per cycle and raises the risk of miscarriage, especially after about 40.
Male ageMen produce sperm throughout life, but sperm quality also declines gradually, usually more modestly — particularly from the 40s onward.

Every person is different, which is why we measure rather than assume. If you are not ready for pregnancy yet, egg freezing can preserve eggs at their current age.

Read about egg freezing →

Understanding your cycle & ovulation

A cycle is counted from the first day of your period. Ovulation usually happens around 14 days before the next period starts — so in a 28-day cycle that is around day 14, but in longer or shorter cycles it moves.

The fertile windowPregnancy is most likely from intercourse in the five days before ovulation and on the day itself. Having sex every two to three days through the cycle covers it without the stress of exact timing.
Signs of ovulationClearer, stretchy cervical mucus, a slight rise in body temperature after ovulation and, for some women, mild one-sided pelvic discomfort.
TrackingA period calendar, home ovulation (LH) test strips and basal temperature charts can all help. Ultrasound follicle tracking at the clinic shows ovulation most precisely.

Very irregular, very painful or absent periods are worth discussing with a doctor — they can be a sign of an ovulation problem or a condition such as PCOS or endometriosis.

When to see a specialist

International guidance (such as that of the American Society for Reproductive Medicine) suggests seeking a fertility evaluation after:

  1. Under 3512 months of regular, unprotected intercourse without pregnancy.
  2. 35 to 396 months of trying without pregnancy.
  3. 40 and overSee a specialist straight away, before or as soon as you start trying.
  4. Known issuesIrregular or absent periods, known endometriosis, past pelvic infection or surgery, a known sperm problem, repeated miscarriage or past cancer treatment — come in early, whatever your age.
Not sure? Take the 1-minute fertility check →

Common causes of infertility

Infertility is a medical condition, not anyone’s fault — and it affects men as often as it is assumed to affect women. Sometimes more than one factor is involved, and sometimes no clear cause is found (unexplained infertility).

Ovulation disorders & PCOSPolycystic ovary syndrome, thyroid problems, high prolactin, or being very under- or overweight can stop regular ovulation. Often very treatable.
Tubal factorsBlocked or damaged fallopian tubes — often from past infection, surgery or endometriosis — stop egg and sperm from meeting.
EndometriosisTissue like the womb lining grows outside the uterus, causing pain, scarring and inflammation that can affect the ovaries and tubes.
Uterine factorsPolyps, fibroids, scar tissue or a septum inside the uterus can make implantation harder. Many can be treated with hysteroscopy.
Male factorLow sperm count, poor movement or abnormal shape, sometimes linked to varicocele, hormones, infection, heat, smoking or medication. A simple semen analysis is the first step.
UnexplainedWhen standard tests are normal. This is common, and treatments such as IUI or IVF can still help.

Fertility tests explained

A first work-up usually checks the three essentials together: eggs and ovulation, the uterus and tubes, and sperm. Your doctor will choose which tests you actually need.

AMH blood testEstimates ovarian reserve — how many eggs remain. It helps plan treatment but does not measure egg quality or predict natural pregnancy on its own.Learn more →UltrasoundShows the uterus and ovaries, counts resting follicles (antral follicle count) and can track ovulation.Learn more →
Semen analysisMeasures sperm count, movement (motility) and shape (morphology). Usually done after two to five days without ejaculation.
HSG (tube test)An X-ray with contrast dye that shows whether the fallopian tubes are open and outlines the uterine cavity.
HysteroscopyA thin camera looks directly inside the uterus to find — and often remove — polyps, fibroids or scar tissue.Learn more →LaparoscopyKeyhole surgery to diagnose and treat endometriosis, adhesions, cysts or tubal problems.Learn more →

The treatment ladder

Treatment usually starts with the simplest option that fits your diagnosis and moves up only if needed. Age, test results and how long you have been trying all shape where you start.

  1. Lifestyle & timed intercourseTreat any underlying problem, optimise health and, if needed, use medication to help ovulation, with ultrasound timing.
  2. IUIPrepared sperm placed directly into the uterus at ovulation. Gentle, with no anaesthesia.
  3. IVF & ICSIEggs are collected and fertilised in the lab; with ICSI, a single sperm is injected into each egg.
  4. Blastocyst culture & PGTEmbryos are grown to day 5 so the strongest can be chosen, and can be genetically tested before transfer if advised.
  5. Egg freezingFor later: eggs are vitrified now and kept for a future pregnancy attempt.
IUI & GIFT →IVF & ICSI →Blastocyst culture & PGT →Egg freezing →

Lifestyle tips for both partners

Lifestyle cannot fix every fertility problem, but these well-established steps support your chances — naturally or with treatment.

  1. Healthy weightBeing well under- or overweight can disrupt ovulation and affect sperm. Even modest weight change can help.
  2. Stop smokingSmoking harms eggs and sperm and is linked to earlier menopause. Both partners should quit.
  3. Limit alcoholAvoiding alcohol is safest when trying to conceive and in pregnancy; men should keep within low-risk limits.
  4. Moderate caffeineKeep to around 200 mg a day — roughly one to two cups of coffee.
  5. Folic acidTake 400 micrograms daily, ideally starting at least a month before trying. Some women need a higher dose — ask your doctor.

Myths vs facts

“Infertility is usually the woman’s problem.”

Fact Male factors are common. That is why we test both partners from the start.

“If I’m healthy, my age doesn’t matter.”

Fact A healthy lifestyle helps, but it cannot stop egg numbers and quality from declining with age.

“Years on the pill harm future fertility.”

Fact Fertility usually returns soon after stopping hormonal contraception. The pill does not use up eggs.

“We already have a child, so we can’t have a problem.”

Fact Difficulty conceiving after a previous pregnancy (secondary infertility) is common and worth checking.

“IVF always means twins.”

Fact Transferring a single healthy blastocyst greatly lowers the chance of twins.

“Lying with your legs up after sex helps.”

Fact There is no good evidence for this. Sperm reach the cervix within minutes.

Glossary

AMH
Anti-Müllerian hormone, a blood test that estimates ovarian reserve.
Ovarian reserve
The number of eggs remaining in the ovaries.
Antral follicle count
Small resting follicles counted on ultrasound; another measure of ovarian reserve.
Blastocyst
An embryo at day 5–6 of development, with an inner cell mass and an outer layer that forms the placenta.
IUI
Intrauterine insemination: prepared sperm placed in the uterus around ovulation.
IVF
In vitro fertilisation: eggs and sperm are joined in the laboratory.
ICSI
Intracytoplasmic sperm injection: one sperm injected directly into each egg.
PGT
Preimplantation genetic testing: a few cells from a blastocyst are checked before transfer.
Embryo transfer
Placing an embryo into the uterus through a fine catheter — quick and usually painless.
Vitrification
Ultra-rapid freezing used for eggs and embryos, which avoids damaging ice crystals.
Ovarian stimulation
Hormone medication that helps several eggs mature in one cycle for IVF.
PCOS
Polycystic ovary syndrome, a common hormonal condition that can cause irregular ovulation.

Fertility questions, answered

How long should we try before seeing a doctor?

Generally 12 months if the woman is under 35, 6 months if she is 35–39, and straight away from 40 or if there is a known problem such as irregular periods or endometriosis.

Does my AMH level tell me whether I can get pregnant?

Not on its own. AMH estimates how many eggs remain, which helps plan treatment such as IVF or egg freezing. It does not measure egg quality, and women with low AMH can still conceive.

Should my partner be tested too?

Yes. Male factors are common, and a semen analysis is simple and non-invasive. Testing both partners together saves time.

Is IVF the only option?

No. Depending on the cause, treating an underlying problem, ovulation medication or IUI may be enough. IVF is recommended when simpler steps are unlikely to work or have not worked.

When is the best time to freeze my eggs?

Eggs frozen at a younger age — generally before the mid-30s — tend to give better chances later. An AMH test and ultrasound help decide whether and when it makes sense for you.

What should I bring to my first consultation?

Any previous test results, a note of your recent cycle dates, and your partner if possible. The first consultation at DBN is free.

See all clinic FAQs →

Ready to talk it through?

Book a free first consultation with Dr. Tongtis — our team replies on LINE in minutes.

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This guide is general information, not a diagnosis or a substitute for medical advice. Please consult a doctor about your own situation.

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