Biological clock for women – fertility after 35, ovarian reserve and egg quality

Fertility changes gradually: it becomes measurable in the early 30s, accelerates after 35, and is noticeably reduced after 40. This is not meant to alarm, but to encourage getting clarity in time. If you know your ovarian reserve, how quality declines with age, and which options are realistic, you can make better decisions—whether trying naturally, optimising timing, or considering social egg freezing.

For reliable guidance we recommend guidelines and databases such as NICE: Fertility problems, NHS: Infertility, the CDC ART statistics, and position papers from ESHRE and the WHO.

Ovarian reserve (AMH & AFC) – your biological "savings account"

The number of follicles is set at birth and declines throughout life. Two measures give a good overview of the remaining reserve today:

• AMH (anti-Müllerian hormone): A blood value that reflects the size of the active follicle pool. Low AMH indicates a smaller reserve, high AMH a larger one.
• AFC (antral follicle count): Ultrasound count of small follicles at the start of the cycle; together with AMH it is informative for planning.

Interpretation should be done by experienced clinicians. NICE recommends structured investigations before therapy decisions are made.

Age & egg quality: what happens in the ovary

• Chromosome distribution: Aneuploidy increases with age, which raises miscarriage risk and can make implantation harder.
• Mitochondria & energy: Eggs from older women often have reduced "energy reserves", which can affect early embryo stages.
• Hormonal dynamics: Cycle phases can shorten; the "window" for implantation may become narrower.
• Overall effect: Lower reserve and reduced egg quality explain why additional support is often helpful from the mid/late 30s onward.

Numbers & success rates – realistic expectations

Natural chance per cycle: roughly 25–30% under 30, 10–15% at 35 and often <5% from 40. These ranges vary with cycle regularity, partner sperm and preexisting conditions.

Miscarriage risk: increases with age (aneuploidy). Individual counselling is recommended, especially after recurrent losses.

IVF/ICSI: Age-related success rates can be found in national registries; the CDC ART National Summary and the Success Estimator provide good overview data.

Improving egg quality – the effective levers

• Not smoking: Tobacco accelerates ovarian ageing; quitting has immediate benefits.
• Weight & metabolism: Aim for a stable BMI in the normal range and good insulin sensitivity.
• Alcohol & environment: Avoid heavy consumption; reduce exposure to endocrine disruptors (BPA/plasticizers).
• Sleep & shift work: Consistent sleep times support hormonal balance.
• Exercise & stress management: Moderate training, breathing and relaxation techniques.
• Partner check: A semen analysis clarifies whether male factors contribute.

Guidelines emphasise lifestyle interventions as the foundation—therapeutic options build on these (see NICE, NHS).

Testing fertility – AMH, AFC & cycle tracking

• AMH blood test: Marker of reserve; useful from the early 30s as a baseline, then repeated periodically.
• AFC ultrasound: Counting antral follicles at cycle start; very helpful alongside AMH.
• Cycle tracking: LH urine tests, basal body temperature, cervical mucus or wearables to identify the fertile window.
• Additional diagnostics depending on findings: Thyroid, prolactin, insulin resistance, vitamin D, coagulation; investigate endometriosis if suspected.

Guidance: under 35 seek medical advice after 12 months without pregnancy, at 35 or older after 6 months (recommendation e.g. NHS).

Social Freezing – process, chances & costs

Process

1. 10–12 days of stimulation with daily injections
2. Monitoring with ultrasound and hormone tests
3. Oocyte retrieval under short anaesthesia (≈ 15 minutes)
4. Vitrification at −196 °C

Chances

The younger the eggs at freezing, the higher the later chance per egg. Under 35 target ranges of about 12–20 eggs are often discussed; with increasing age the probability per egg decreases. See ESHRE guidance for ethical/medical aspects: ESHRE.

Costs

• Stimulation cycle: approx. €3,000–4,500
• Storage per year: approx. €200–300
• Reimbursement usually only for medical indications

For context on success rates consult national registries, e.g. the CDC data.

Preexisting conditions & risks – when to look closer

Factors that may play a role include endometriosis (adhesions, pain), PCOS (ovulatory disorders, insulin resistance), thyroid dysfunction, hyperprolactinaemia, clotting disorders (e.g. factor V Leiden). With cycle irregularities, severe pain, recurrent miscarriages or 6–12+ months of unsuccessful attempts, referral to a fertility clinic is advisable.

Your plan from today

1. Baseline check: Get AMH & AFC measured in the coming weeks.
2. Sharpen timing: Track 2–3 cycles with LH tests + basal temperature.
3. Leverage lifestyle: Quit smoking, regular sleep, exercise, balanced diet, reduce alcohol.
4. Clarify options: Natural attempts vs. IUI/IVF, possibly social freezing; arrange individual counselling.
5. Check partner factor: Plan a semen analysis if appropriate.

Sperm donation with RattleStork – option without a partner

If a partner is missing or male factors limit fertility, you can explore screened donor profiles via the RattleStork app, make contact and plan procedures—from anonymous donation to co-parenting or at-home insemination. This helps you make informed decisions suited to your situation.

Conclusion

You cannot stop time—but you can use it. Knowing your reserve and risks, optimising timing and soberly assessing options like social freezing or assisted reproduction measurably improves chances. For orientation and planning see the WHO, NICE, NHS, CDC ART, ESHRE.