People often scan their flow, cycle length, or PMS symptoms to guess whether their eggs are still "good." It is understandable, but period features are not a reliable test of egg quality. Clinically, egg quality means whether an egg can create a healthy, chromosomally normal embryo (euploid) that can implant and grow. The strongest predictor of that is age, not how your last period looked.
Want a quick read on your likely fertile window based on your own dates? Use the Period Calculator on our homepage to generate a personalized calendar.
What Egg Quality Means in Practice
- Chromosomal normality: Aneuploidy risk climbs with maternal age because of age-related meiotic errors. Preimplantation genetic testing for aneuploidy (PGT-A) data and large reviews show the same pattern: a rising share of embryos are chromosomally abnormal as age advances.
- Developmental competence: Beyond chromosomes, laboratory observations track how embryos progress, including energy use and spindle integrity. These age-related shifts are documented in embryology labs, not something your period can diagnose.
What Your Period Can - and Cannot - Tell You
- Cycle traits reflect timing, not egg health. Short or long cycles, heavy or light flow, and more or fewer cramps do not directly measure egg quality. Epidemiology studies connect cycle features to ovulation timing and, at extremes, to certain risks, but they are weak personal diagnostics.
- Ovulation timing is not fixed at day 14. Ovulation varies between people and across cycles. Relying on cycle length alone to pinpoint ovulation misses that variability for most individuals.
- Know when to check in. If cycles are consistently shorter than 21 days, longer than 35 days, skipped often, or accompanied by atypical bleeding, schedule a clinician visit. Those patterns can signal ovulatory or endocrine issues, yet they still do not grade egg quality.
Tests That Do Inform (and Their Limits)
1) AMH and AFC: Quantity, not quality
Anti-Mullerian hormone (AMH) and antral follicle count (AFC) estimate ovarian reserve, meaning how many follicles are likely recruitable. They do not predict embryo quality or your chance of conceiving naturally in any specific month. ASRM and ACOG caution against using AMH as a stand-alone "fertility score." These measures are valuable for planning treatment, such as forecasting egg yield for IVF or egg freezing, and for flagging low ovarian response, but they correlate only weakly with pregnancy or live birth outcomes once age is factored in.
2) Day-3 FSH and estradiol
Elevated day-3 follicle-stimulating hormone (FSH) with estradiol can suggest diminished ovarian reserve. Even so, these labs are moderate predictors at best and provide less information than AMH or AFC for treatment planning. They do not directly measure egg quality.
3) PGT-A and embryo morphology after IVF
PGT-A checks embryo chromosomes and consistently demonstrates the rise of aneuploidy with age. It is useful after embryos exist, but it is not a general screening tool for people not undergoing IVF, and a normal (euploid) embryo is not guaranteed to implant.
Common Myths vs Evidence
- "Light or short periods mean better eggs." Flow and bleed length vary for many reasons, including hormones, contraception, and uterine factors. There is no consistent clinical evidence that they reflect egg health.
- "AMH tells me my egg quality." AMH reflects quantity, not quality or future natural fertility on its own. Major guidelines warn against marketing it as a definitive fertility score.
- "Perfect tracking lets me judge quality." Ovulation tracking with LH kits, basal body temperature, or wearables can improve timing and reduce time to pregnancy, but none of these tools grade egg quality.
What Does Help Your Chances
- Work with age, not against it. If childbearing is a goal and age is advancing, consider timelines early. Natural conception and assisted reproduction success rates both decline with age.
- Optimize the basics. Aim for a healthy weight, avoid smoking, limit alcohol, and take preconception folate. These factors influence fecundability and pregnancy outcomes, even when chromosomes are normal.
- Time intercourse well. Use the Period Calculator to view your likely fertile window, then add ovulation tracking if you want additional precision.
- Seek individualized advice. If cycles are consistently very short or long, if bleeding patterns change dramatically, or if you have been trying for 12 months (under 35) or 6 months (35 and older), ask for a tailored evaluation.
Bottom Line
Your period is a useful calendar, not a microscope for egg health. Age remains the dominant driver of egg competence. AMH and AFC quantify how many eggs are likely recruitable, not how good they are. Embryo chromosome testing becomes relevant only after IVF. Use cycle tools to time intercourse, and rely on clinical testing plus one-to-one care for decisions that period symptoms cannot answer.
References
- ASRM Practice Committee (2020). Testing and interpreting measures of ovarian reserve: a committee opinion. AMH and AFC predict response quantity better than pregnancy outcomes linked to quality.
- ACOG Committee Opinion (2019). The use of anti-Mullerian hormone in women not seeking fertility care. AMH should not be marketed or used as a stand-alone fertility or egg-quality test.
- ASRM Practice Committee (2024). The use of PGT-A: a committee opinion. Aneuploidy rises with maternal age; PGT-A assesses embryo chromosomes after IVF.
- Endotext (NIH Bookshelf, 2022). Ovarian reserve testing overview. Age is the best predictor of pregnancy; AMH and AFC help forecast ovarian response; FSH trends are less predictive.
- Reviews on menstrual cycles and ovulation timing (2019-2024). Cycle length offers population-level associations but does not diagnose egg quality for individuals.
- CDC Assisted Reproductive Technology (ART) Reports (2024). National age-stratified success data underscore the age and outcome relationship.