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
- Ovulation
- Ovarian reserve
- Fallopian tubes and uterus
- Hormonal and metabolic health
- Conditions such as PCOS (PMOS), endometriosis and thyroid disorders
- Sperm health 1
- Lifestyle and overall health
Being healthy supports fertility, but cannot completely prevent age-related reproductive changes. 2
India’s Reproductive Timeline Is Changing
Indian women are spending more years in education, employment and financial independence before marriage and parenthood. That social change is important. But our social timeline and biological timeline are not identical. Government data show that the mean age at effective marriage for Indian women was 22.1 years in 2019, compared with approximately 23.3 years in urban areas and 21.7 years in rural areas. 6
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 miscarriage risk. 2 3
Fertility does not suddenly disappear at 35. It declines gradually, with the decline becoming faster in the mid-30s. By 40, natural fertility is substantially lower. 2
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 (PMOS)
- 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. 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
PCOS (PMOS), Endometriosis and Fertility
- PCOS (PMOS): PCOS (PMOS) can interfere with ovulation and is an important cause of ovulatory infertility. But PCOS (PMOS) 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.
- 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 or 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 pregnancy is planned, take folic acid as advised by your healthcare professional.
- 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 with:
- Very irregular or absent periods
- Known PCOS (PMOS)
- Endometriosis
- Previous pelvic surgery
- Known tubal problems
- 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 About Egg Freezing?
Egg freezing can preserve the possibility of using one’s own eggs later, but it is not a guarantee of a future baby. Age at freezing matters because egg quality declines with age. Think of it as: an option to discuss—not an insurance policy.Assisted reproductive technology cannot completely erase age-related changes in egg quality. 3
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 (PMOS), 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
Key Takeaways
- Fertility depends on age, egg quality, ovulation, ovarian reserve, reproductive anatomy, hormones, health and sperm factors.
- Fertility declines gradually with age, becoming more noticeable through the mid-to-late 30s.
- Ovarian reserve and fertility are not the same thing.
- AMH is not a standalone fertility test. 4
- PCOS (PMOS), endometriosis and thyroid disorders can affect fertility.
- Untreated overt hypothyroidism is associated with increased pregnancy risks, including miscarriage. 5
- Infertility affects both women and men. 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.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.https://www.acog.org/clinical/clinical-guidance/committee-statement/articles/2025/11/anticipatory-counseling-regarding-ovarian-factor-fertility-decline
[4] American Society for Reproductive Medicine. Testing and Interpreting Measures of Ovarian Reserve: A Committee Opinion.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.https://pubmed.ncbi.nlm.nih.gov/33680424/
[6] Government of India, Ministry of Statistics and Programme Implementation. Youth in India 2022.https://www.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.https://www.asrm.org/practice-guidance/practice-committee-documents/fertility-evaluation-of-infertile-women-a-committee-opinion-2021/