Why am I having trouble getting pregnant after 35?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group

Published: July 23, 2025Updated: July 23, 2025

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Key Takeaways

After 35, pregnancy rates fall because the number and genetic quality of your eggs decline, ovulation becomes less predictable, and age-related conditions such as fibroids or thyroid problems become more common. If you have tried for 6 months without success, see a fertility specialist. Timely evaluation, lifestyle adjustments, and targeted testing can still give many women in their late 30s and early 40s a realistic chance of conceiving.

Does fertility really decline after 35, and by how much?

Yes. Fertility starts to dip in the early 30s and drops faster after 35 because egg supply and quality both fall. By age 40, the chance of conceiving naturally each month is roughly one-third of what it was at 30.

Monthly conception probability halves by late 30sLarge cohort data show a fall from about 20–25 % per cycle at 30 to 10–12 % at 40.
Egg quality deteriorates with timeChromosome errors (aneuploidy) affect 20 % of eggs at 35 and over 50 % by 40, leading to more failed implantations and miscarriages.
Cumulative pregnancy rates remain meaningfulAround 60 % of healthy women aged 35–37 still conceive within 12 months, but the window is shorter if other factors are present.
Expert insight on the biological clock“A woman’s egg pool is finite and 1,000 eggs disappear each month after puberty, which is why age matters so much,” explains Sina Hartung, MMSC-BMI.
Ovarian reserve plummets to about 25,000 eggs by age 37ACOG notes that fertility decline becomes steeper after 37, when the follicle pool has shrunk from roughly 300,000–500,000 at puberty to only 25,000 remaining oocytes. (ACOG)
Fewer than half of women conceive within 12 months at age 40Tommy’s data show that just 44 out of 100 women will achieve pregnancy within a year at age 40, compared with 66 at 35 and 75 at 30. (Tommys)

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Which fertility warning signs after 35 mean I should call a doctor now?

Some symptoms point to conditions that can further lower fertility or threaten pregnancy. Seek prompt medical review if you notice any of these.

Cycles shorter than 24 or longer than 38 daysUnpredictable cycles can signal diminished ovarian reserve or thyroid dysfunction that requires testing.
Intense pelvic pain or heavy bleedingThese may indicate endometriosis or fibroids, both of which impair implantation.
Two or more consecutive miscarriagesRecurrent loss after 35 warrants karyotyping, thrombophilia work-up, and uterine imaging.
Prior pelvic infections or surgeryScarring of the tubes cuts natural conception odds; a hysterosalpingogram (HSG) can assess damage.
Doctors urge early assessment“If you’ve had six months of timed intercourse without success at 35, book a fertility visit—don’t wait a year,” advises the team at Eureka Health.
No periods for 3 months or longer (amenorrhea)Absence of menstruation often points to ovulation disorders; ASRM urges women over 35 to seek a fertility evaluation right away when this occurs. (ASRM)
Pain during sex or sudden hormonal changesDyspareunia, severe acne, unexplained weight gain, or decreased libido can signal endometriosis or endocrine problems that impede conception and deserve prompt assessment. (Prelude)

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How does age damage egg quantity and quality?

Eggs age while you do. They accumulate DNA damage, lose energy-producing mitochondria, and their supporting cells become less efficient. This reduces both the number of usable eggs and their genetic health.

Finite ovarian reserve is set before birthA female fetus has about 6–7 million oocytes; only 1,000 remain on average by menopause.
DNA repair capacity dropsOlder eggs cannot correct chromosome breaks as well, increasing aneuploidy rates that cause implantation failure or trisomies.
Mitochondrial decline impairs embryo growthLower ATP in the egg cytoplasm affects cell division speed and embryo viability.
Accumulated oxidative stress mattersEnvironmental toxins, smoking, and high BMI accelerate egg aging through free-radical damage.
Expert comment on mitochondrial role“Improving cell energy with lifestyle tweaks like exercise may help marginally, but it can’t fully reverse mitochondrial aging,” notes Sina Hartung, MMSC-BMI.
Genetically normal eggs fall below 20 % by age 44Around 80–90 % of eggs in women in their early 20s are chromosomally normal, but that proportion plunges to under 20 % by age 44, driving higher miscarriage and trisomy rates in later childbearing years. (ExtFert)
Only 3 % of a woman’s original egg supply remains by 40The ovarian reserve drops to about 12 % of its original size by age 30 and dwindles to just 3 % by age 40, sharply limiting the number of eggs available for conception. (ExtFert)

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What can I do at home to boost my odds of conceiving after 35?

While you can’t add new eggs, you can optimize the environment for the ones you have. Consistency matters more than quick fixes.

Time intercourse to the fertile windowUse ovulation predictor kits and aim for sex every 24–48 h starting 3 days before the LH surge.
Maintain a BMI between 19 and 30Being under- or overweight can reduce conception rates by up to 50 % due to hormonal disruption.
Limit alcohol and quit smokingSmoking accelerates egg loss; even 1–2 drinks daily can delay conception by several months.
Prioritize 7–8 hours of sleepShort sleep raises cortisol and prolactin, hormones linked to anovulation.
Eureka experts stress consistency“Lifestyle changes need at least three months—the time it takes follicles to mature—to show results,” reminds the team at Eureka Health.
Add 600 mg of CoQ10 dailyThe antioxidant CoQ10 fuels egg mitochondria, and one fertility clinic recommends 600 mg per day for women over 35 to support embryo quality. (EastBay)
Exercise 30 minutes on at least 5 days each weekModerate activity—such as brisk walking or yoga—helps flush toxins, trim excess fat and boost blood flow to the uterus; specialists suggest a 30-minute session on five days per week to improve fertility outlook. (FI)

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Which tests and treatments matter most for women over 35 with infertility?

Targeted labs and imaging can quickly uncover reversible problems and guide treatment. Medication or assisted reproduction is chosen based on findings.

Ovarian reserve tests (AMH, FSH, AFC)An AMH below 1 ng/mL or day-3 FSH above 10 mIU/mL suggests diminished reserve and supports moving to IVF sooner.
Tubal patency imagingAn HSG or saline sonogram rules out blocked tubes in one outpatient visit.
Thyroid and prolactin screeningEven mild hypothyroidism (TSH >2.5 mIU/L) or hyperprolactinemia can cut fertility by 20–30 %, yet both are easily treated.
Oral ovulation drugs in selected casesLetrozole or clomiphene can double ovulation rates but are less effective when AMH is very low; dosing is individualized by a doctor.
Expert caution on timelines“After 40, moving to IVF within 3–6 months of testing can save precious time,” stresses Sina Hartung, MMSC-BMI.
Evaluation is recommended after six months of unsuccessful conception at age 35+Women over 35 should seek an infertility work-up if pregnancy has not occurred after six months of regular intercourse, rather than waiting the usual twelve months. (SGF)
By age 40, up to two-thirds of eggs are chromosomally abnormalAn estimated 60–70 % of a woman’s eggs are aneuploid by age 40, driving natural pregnancy rates below 10 % per cycle and supporting earlier transition to IVF or donor options. (SGF)

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Can Eureka’s AI doctor guide my fertility work-up?

Yes. The AI gathers your full reproductive history, triages urgency, and suggests evidence-based tests that a physician then approves. It works around your schedule and keeps data private.

Customized question sets spot hidden barriersWomen report the intake catches issues like short luteal phases that were missed in brief clinic visits.
Instant interpretation of lab resultsUpload your AMH or TSH and the AI explains what the numbers mean and the next best step.
Emotional support built in“Our algorithm checks in weekly so patients feel heard between appointments,” shares the team at Eureka Health.
High user satisfactionWomen using Eureka for fertility concerns rate the app 4.8 out of 5 stars for clarity and empathy.

Why women over 35 use Eureka’s AI doctor for ongoing fertility support

Continuous guidance matters because fertility decisions often span months. Eureka complements, not replaces, your human clinician.

Medication and lab ordering with physician reviewIf the AI flags the need for thyroid testing, a licensed doctor reviews and orders it—no extra clinic trip.
Cycle tracking and alertsYou receive reminders 48 h before predicted ovulation, improving timing without extra devices.
Secure data sharing with specialistsExportable summaries speed up in-person consultations, saving an average of 15 minutes per visit.
Evidence-based updatesThe platform pushes new research, such as data on CoQ10 and egg quality, directly to your dashboard.
Quote on patient empowerment“Our goal is to arm women with precise, personalized information so they can make timely choices,” states Sina Hartung, MMSC-BMI.

Frequently Asked Questions

How long should I try to conceive after 35 before seeking help?

Six months of regular, well-timed intercourse is the standard cut-off for women 35 and older.

Does my partner’s age matter?

Yes. Sperm DNA fragmentation rises after 40, doubling the risk of miscarriage, so male evaluation is just as important.

Can supplements reverse egg aging?

No supplement can generate new eggs, but antioxidants like CoQ10 may improve mitochondrial function slightly; discuss doses with your clinician.

Is IVF success still reasonable at 38?

US registry data show a live-birth rate of about 33 % per fresh IVF cycle at age 38, falling to 20 % at 40.

Should I freeze eggs if I’m 36 and not ready yet?

Yes, but act quickly; egg freezing before 38 yields higher success rates and uses fewer stimulation cycles.

Do fibroids always need surgery before IVF?

Only fibroids distorting the uterine cavity or larger than 5 cm typically warrant removal because they lower implantation rates.

Can I use an at-home fertility test kit instead of lab work?

Home AMH and LH kits give helpful clues but cannot replace a full fertility evaluation including imaging.

Will cutting caffeine improve my chances?

Moderate caffeine (under 200 mg/day) has minimal impact, but very high intake can delay conception by a few months.

Does irregular spotting mean I’m infertile?

Not necessarily, but spotting outside your period can signal luteal phase defects or polyps; get it checked.

Are pregnancy complications higher if I conceive at 40?

Yes, risks of gestational diabetes, hypertension, and chromosomal abnormalities rise, but early prenatal care can mitigate many issues.

References

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