Fertility isn't just about having eggs
Maybe you're 28 and everyone says, "You have plenty of time."
Or you're 35 and suddenly people ask, "When are you planning a baby?"
Perhaps you're 30 with irregular periods. Or 36, healthy and active, but pregnancy isn't happening as quickly as expected.
Then come the fertility terms: AMH, egg quality, ovulation, thyroid, estrogen, progesterone, PCOS, endometriosis and IVF.
It can become overwhelming.
The truth is simpler: female fertility is not one number.
It reflects age, ovulation, egg quality, ovarian reserve, fallopian tubes, uterus, hormones, sperm and overall health. [1] [2]
Understanding fertility isn't about creating fear. It is about replacing pressure and vague reassurance with useful information.
Quick answer
The major factors affecting female fertility are:
- Age, because egg quantity and quality change over time [2] [3]
- Ovulation
- Ovarian reserve
- Fallopian tubes and uterus
- Hormonal and metabolic health
- Conditions such as PCOS, endometriosis and thyroid disorders
- Sperm health [1]
- Lifestyle and overall health
Being healthy supports fertility, but cannot completely prevent age-related reproductive changes. [2] [3]
One note on names. PCOS — polycystic ovary syndrome — was renamed polyendocrine metabolic ovarian syndrome, or PMOS, by international consensus in 2026. [8] Nothing about diagnosis or treatment changed, and PCOS remains the term used in clinics and lab reports during the transition, so this article uses it throughout.
India's reproductive timeline is changing
Indian women are spending more years in education, employment and financial independence before marriage and parenthood.
Government data reflect that shift. The proportion of women aged 15–29 who had never married rose from 13.5% in 2011 to 19.9% in 2019. [6]
That social change is important. But our social timeline and our biological timeline are not identical.
This does not mean women should marry or have children earlier. It means fertility education becomes more important when parenthood happens later.
A woman deserves to understand her reproductive timeline before she has to make decisions about it.
Age: the factor we cannot ignore
Women are born with a lifetime supply of eggs, and that supply declines over time.
But quantity isn't the whole story. Egg quality changes too. With increasing age, eggs are more likely to have chromosomal abnormalities, contributing to lower conception rates and higher miscarriage risk. [2] [3]
Fertility does not suddenly disappear at 35. It declines gradually from around the early thirties, more noticeably from the late thirties, and by 40 natural fertility is substantially lower. [2] [3]
This isn't a biological deadline. It is biological information.
Ovulation: the monthly event that matters
Ovulation is the release of an egg from the ovary.
It may become irregular because of:
- PCOS
- Thyroid disorders
- Significant weight changes
- Very low energy availability
- Excessive exercise
- High prolactin levels
- Perimenopause
- Certain medical conditions or medicines
Regular periods make ovulation more likely, but do not guarantee fertility.
Irregular periods do not automatically mean infertility. They mean ovulation deserves attention.
Estrogen, progesterone and the fertility cycle
Fertility involves communication between the brain, pituitary gland and ovaries.
Estrogen rises before ovulation and helps the uterine lining develop, while participating in the hormonal signalling that leads to ovulation.
After ovulation, progesterone from the corpus luteum prepares and supports the uterine lining for possible implantation.
If pregnancy does not occur, these hormones fall and menstruation begins.
So fertility isn't simply about producing an egg. Ovulation, hormones and the uterine environment have to work together.
A single hormone result can also be misleading without considering when it was measured in the menstrual cycle.
Ovarian reserve: what does AMH really tell you?
You may hear: "Get an AMH test. It will tell you how fertile you are."
It doesn't.
Ovarian reserve mainly refers to the quantity of eggs remaining in the ovaries. AMH and antral follicle count can provide useful information about ovarian reserve, particularly during fertility treatment.
But ovarian reserve is not the same as fertility. [4]
A woman can have a reassuring AMH and still have difficulty conceiving because of age-related egg quality, blocked tubes, endometriosis, ovulation problems or sperm factors. A woman with a lower AMH can still conceive.
ASRM cautions against using ovarian-reserve tests as standalone predictors of natural fertility in women who are not being evaluated for infertility. [4]
Remember: AMH is information, not a fertility countdown clock.
The thyroid question
For Indian women, thyroid health deserves particular attention.
An Indian meta-analysis of 61 studies involving 60,066 pregnant women estimated hypothyroidism during pregnancy at 11.07%. Subclinical hypothyroidism accounted for about 9.51%, while overt hypothyroidism was estimated at 2.74%. These figures concern pregnant women, not all Indian women. [5]
Thyroid dysfunction can affect menstrual cycles, ovulation, conception and pregnancy.
Can thyroid disease increase miscarriage risk?
Untreated overt hypothyroidism is associated with increased pregnancy risks, including miscarriage. [5]
But thyroid disease should not automatically be blamed for an individual miscarriage. Pregnancy loss has many possible causes.
The practical message is simple. If you have thyroid disease and are planning pregnancy, get it appropriately assessed and managed. And do not stop thyroid medication on your own after becoming pregnant.
Fertility is a couple's story
One of the most important things we can change in Indian fertility conversations is this: infertility is not automatically a woman's problem.
WHO estimates that approximately 1 in 6 people of reproductive age worldwide experience infertility during their lifetime. [1]
Infertility may involve female factors, male factors, both partners, or no single identifiable cause.
Female factors can include ovulation disorders, endometriosis, tubal disease and uterine conditions. Male factors can involve sperm count, movement or morphology.
Both partners deserve evaluation. [1] And in practice, the male partner's first test is the simpler one — a semen analysis is a single, inexpensive, non-invasive test. There is no medical reason for a woman to undergo months of investigation before it is done.
Conditions that can affect fertility
PCOS
PCOS can interfere with ovulation and is an important cause of ovulatory infertility. But PCOS does not mean a woman cannot become pregnant. Many women conceive naturally or with treatment.
Endometriosis
Endometriosis can affect fertility through inflammation, adhesions and ovarian or tubal involvement.
Tubal damage and pelvic infection
The fallopian tubes are where egg and sperm normally meet, so damage or blockage can prevent conception even when ovulation and hormones are entirely normal. Tubes can be damaged by past pelvic infection, previous pelvic or abdominal surgery, and endometriosis.
Genital tuberculosis deserves specific mention in India. It can affect the fallopian tubes and the lining of the uterus, often silently, and it is an established contributor to tubal infertility here in a way it is not in most Western countries. If you have a history of tuberculosis, or a close contact who has had it, tell your doctor when you are being evaluated — it changes what they look for.
Fibroids and adenomyosis
Depending on their location and extent, these conditions may affect reproductive outcomes.
Thyroid disorders
Thyroid dysfunction can interfere with reproductive function when inadequately treated.
This is why fertility assessment should never become: "Let's just check her eggs."
What does lifestyle have to do with fertility?
Lifestyle supports reproductive health, but there is no fertility detox and no perfect fertility diet.
Focus on the basics.
Eat well. Choose a balanced diet with adequate protein, vegetables, fruits, whole grains, pulses and healthy fats. If you are planning pregnancy, start folic acid before you conceive rather than after a positive test — the neural tube closes in the first few weeks, often before a woman knows she is pregnant. Your doctor will advise the right dose for you, which is higher in some situations.
Maintain metabolic health. Both underweight and obesity can affect ovulation.
Move regularly. Regular activity supports health, while extreme exercise combined with inadequate energy intake can disrupt ovulation.
Avoid smoking and excessive alcohol.
Protect sleep and mental wellbeing.
And remember: stress is not a universal explanation for infertility. Telling someone to "just relax" is neither medically useful nor compassionate.
When should you seek fertility help?
For women under 35, evaluation is generally recommended after 12 months of regular unprotected intercourse without pregnancy.
For women 35 or older, evaluation is generally recommended after 6 months.
For women over 40, earlier or immediate evaluation may be appropriate. [7]
Seek help sooner if you have:
- Very irregular or absent periods
- Known PCOS
- Endometriosis
- Previous pelvic surgery
- Known tubal problems
- A history of pelvic infection or tuberculosis
- Recurrent pregnancy loss
- Significant thyroid disease
- A known male fertility problem
- Previous treatment that may affect ovarian function
There is no benefit in waiting longer when a known risk factor already exists. [7]
What does a fertility evaluation actually involve?
Many couples delay because they cannot picture what they are walking into. It is usually less than people fear.
A first evaluation typically looks at four things: whether ovulation is happening, whether the fallopian tubes are open, what the uterus and ovaries look like, and whether the sperm are normal. [7]
In practice that usually means a detailed history for both partners, blood tests timed to the menstrual cycle, a pelvic ultrasound, a test of tubal patency, and a semen analysis for the male partner. Additional tests are added only when the history points towards them.
Not every couple needs every test, and a first visit is often mostly conversation. Going early does not commit you to treatment. It gives you information while you still have the widest range of options.
What about egg freezing?
Egg freezing can preserve the possibility of using your own eggs later, but it is not a guarantee of a future baby.
Age at freezing matters, because egg quality declines with age. Assisted reproductive technology cannot completely erase age-related changes in egg quality. [3]
In India, assisted reproduction including egg freezing is regulated under the Assisted Reproductive Technology (Regulation) Act, 2021, which sets out clinic registration requirements and eligibility criteria. Ask any clinic you are considering about its registration under the Act, and check the current eligibility rules, which have been amended since the Act was passed.
Think of egg freezing as an option to discuss, not an insurance policy.
Your fertility health checklist
You don't need to obsess over fertility. But you can know your body.
- Know your cycle. Notice whether your periods are predictable, very irregular or changing.
- Know your health. Don't ignore PCOS, endometriosis, thyroid disease or significant metabolic problems.
- Know your reproductive plans. You don't need to decide today when you'll have children. Understanding your options can help you make informed decisions.
- Know when to ask for help. That may be the most important one.
From the doctor's desk
"Fertility is not a single test and it is not determined by age alone. We look at ovulation, ovarian reserve, the uterus, tubes, hormones, medical conditions and the male partner as well. The goal is not to frighten a woman with isolated numbers, but to understand her individual reproductive health and give her realistic options."
— Dr. Sowmya Sampurna M, Consultant Obstetrics & Gynaecology
Key takeaways
- Fertility depends on age, egg quality, ovulation, ovarian reserve, reproductive anatomy, hormones, health and sperm factors.
- Fertility declines gradually from around the early thirties and more noticeably from the late thirties. [2] [3]
- Ovarian reserve and fertility are not the same thing.
- AMH is not a standalone fertility test. [4]
- PCOS, endometriosis, tubal damage and thyroid disorders can all affect fertility.
- Untreated overt hypothyroidism is associated with increased pregnancy risks, including miscarriage. [5]
- Infertility affects both women and men, and a semen analysis is a simple first-line test. [1]
- Lifestyle supports reproductive health but cannot erase age-related fertility changes.
- Good fertility education empowers; it does not frighten.
References
[1] World Health Organization. Infertility. Fact sheet. https://www.who.int/news-room/fact-sheets/detail/infertility
[2] American College of Obstetricians and Gynecologists. Having a Baby After Age 35: How Aging Affects Fertility and Pregnancy. https://www.acog.org/womens-health/faqs/having-a-baby-after-age-35-how-aging-affects-fertility-and-pregnancy
[3] American College of Obstetricians and Gynecologists. Anticipatory counseling regarding ovarian-factor fertility decline. Committee Statement No. 22. Obstetrics & Gynecology. 2025;146(5):e98–e104. doi:10.1097/AOG.0000000000006078
[4] American Society for Reproductive Medicine. Testing and Interpreting Measures of Ovarian Reserve: A Committee Opinion. 2020. https://www.asrm.org/practice-guidance/practice-committee-documents/testing-and-interpreting-measures-of-ovarian-reserve-a-committee-opinion-2020/
[5] Yadav V, Dabar D, Goel AD, et al. Prevalence of hypothyroidism in pregnant women in India: a meta-analysis of observational studies. Journal of Thyroid Research. 2021;2021:5515831. doi:10.1155/2021/5515831
[6] Government of India, Ministry of Statistics and Programme Implementation, National Statistical Office. Youth in India 2022. https://mospi.gov.in/sites/default/files/publication_reports/Youth_in_India_2022.pdf
[7] American Society for Reproductive Medicine. Fertility Evaluation of Infertile Women: A Committee Opinion. 2021. https://www.asrm.org/practice-guidance/practice-committee-documents/fertility-evaluation-of-infertile-women-a-committee-opinion-2021/
[8] Teede HJ, Bahri Khomami M, Morman R, et al. Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process. Lancet. Published online May 12, 2026. doi:10.1016/S0140-6736(26)00717-8