Find clear, evidence-based answers to common IVF questions using Remembryo’s existing research, guides and resources. Select a question to jump to a Remembryo article or section where the topic is discussed in more detail. You can also search this page for a specific topic, treatment, test or add-on.
This is a growing resource and isn’t a definitive or complete source of IVF information. Some articles may not reflect the latest research, so always confirm information and treatment decisions with your fertility specialist.
PGT-A & Genetics
Find answers about PGT-A testing, interpreting your results, euploid and mosaic embryos, and success rates after transfer.
Understanding your PGT-A results
- How do I interpret my PGT-A results?
- What’s the difference between a euploid, aneuploid and mosaic embryo?
- What does whole chromosome, trisomy, monosomy, or segmental aneuploidy mean?
- What does a complex or chaotic PGT-A result mean?
- What does a no-result/inconclusive result mean?
- What’s a high level or low level mosaic?
Getting euploid embryos
- What are my chances of getting a euploid embryo at my age?
- Does embryo grade affect the chance of getting a euploid?
- Does the day of biopsy affect the chance of getting a euploid?
- Does the PGT-A testing lab affect the chance of getting a euploid?
- What causes aneuploidy and why did I get so many aneuploid embryos?
PGT-A success rates
- What are the success rates for euploids?
- What are the chances of success after multiple failed euploid embryo transfers?
- Why can a euploid embryo fail to implant or miscarry?
- Does age still matter when transferring a euploid?
- Does embryo grade or day still matter when transferring a euploid?
- Do day 5 euploid embryos have higher success rates than day 6 or day 7 euploid embryos?
- Do poor quality euploids work?
- What are the success rates for mosaics? (Low/high level, whole chromosome/segmental)
- Can mosaic embryos lead to healthy births?
- What are the success rates for aneuploids?
- What are the success rates for chaotic embryos?
- Is it safe to thaw and biopsy an embryo for the first time?
- Is it safe to thaw and rebiopsy an embryo for a second time?
- Why didn’t my euploid survive the thaw?
Embryos & Fertilization
Find answers about fertilization, embryo development, embryo grading, blastocyst formation, embryo arrest, and success rates.
IVF attrition
- How many eggs and blastocysts should I expect for my age?
- What percentage of retrieved eggs should be mature?
- What percentage of fertilized eggs should make it to blastocyst?
- What percentage of good quality day 3 embryos should make it to blastocyst?
- When is a low egg maturity, fertilization, or blastocyst rate unusually low?
- What can someone with 5 or fewer follicles expect?
Low and abnormal fertilization (0PN, 1PN, 3PN)
- What is a normal fertilization rate?
- Is poor fertilization usually due to the sperm or egg?
- Can poor fertilization be predicted before it happens?
- Can artificial oocyte activation (AOA) help with low fertilization?
- What does a 1PN or 3PN fertilization result mean?
- Does a 0PN just mean fertilization was missed?
- Can 0PN, 1PN or 3PN zygotes lead to successful pregnancies?
- Should 1PN or 3PN zygotes be discarded?
Day 3 embryos (cleavage stage) & success rates
- I have a day 3 embryo — what does my embryo grade mean?
- What are the success rates for day 3 embryos?
- My day 3 embryo is fast growing and has more than 8 cells, is that bad?
- Can day 3 embryo quality predict whether it will become a blastocyst?
- Can poor quality day 3 embryos, with few cells or high fragmentation, still work?
- Do poor quality day 3 embryos have a higher chance of pregnancy complications?
Day 5-7 embryos (blastocyst stage) & success rates
- I have a blastocyst (eg. a “4AB”) — what does my embryo grade mean?
- What’s the best (and worst) blastocyst grade?
- What are the success rates for my blastocyst?
- Are day 5 embryos more successful than day 6 embryos?
- Are day 5 embryos more successful than day 7 embryos?
- Are day 6 embryos more successful than day 7 embryos?
- Can poor quality (C-grade) embryos still lead to healthy births?
- Do poor quality blastocysts have a higher chance of pregnancy complications or birth defects?
- Can I transfer a poor and good quality blastocyst together?
- What happens when two poor quality blastocysts are transferred?
- My embryo grade changed after thaw, does that matter?
- Do hatching or hatched blastocysts have better success rates compared to unhatched blastocysts?
- Are hatched blastocysts more fragile?
- Are certain blastocyst grades more likely to be male or female?
- Does embryo grade or day still matter when transferring a euploid?
Embryo compaction
- What does it mean when a blastocyst collapses or looks squished?
- Does embryo re-expansion after thaw affect success?
Day 3 vs day 5 embryos
- Overall, is a day 3 or day 5 embryo transfer better?
- I only have one fertilized egg — is day 3 or 5 better?
- I only have a few fertilized eggs — is day 3 or day 5 better?
Embryo arrest
- Why do embryos stop growing before the blastocyst stage?
- Is embryo arrest due to the sperm or the egg?
- Is it possible to correct embryo arrest?
- All my embryos arrested — does that mean it will happen again in another cycle?
- How much embryo arrest is normal?
Female Reproductive Health & Egg Quality
Find answers about egg quality, egg maturity, ovarian aging, ovarian reserve, endometriosis, supplements, and lifestyle factors that may affect fertility.
Understanding the egg and egg quality
- What does egg quality actually mean?
- What are the parts of the egg?
- What are common egg abnormalities, and do they always mean poor egg quality?
Follicle development & egg maturity
- How do eggs develop in the follicle?
- What’s the difference between an immature (GV, M1) and mature (M2) egg?
- Is a mature M2 egg always fully mature? (nuclear maturity vs cytoplasmic maturity)
- What follicle size is most likely to contain a mature egg?
- What percentage of retrieved eggs should be mature?
- Is a low percentage of mature eggs linked to reduced success rates?
- Can immature eggs be matured in the lab?
- When is a low egg maturity rate unusually low?
- Does the type of trigger shot affect how many mature eggs are retrieved?
- What are my chances of live birth with 5 or fewer follicles?
Frozen eggs
- What percentage of frozen eggs survive thawing?
- Does freezing eggs affect embryo quality?
- How many frozen eggs do I need for a live birth?
- How many frozen eggs do I need for 3 euploids?
Age & ovarian aging
- How does age affect egg quality?
- How does age affect IVF success?
- What are IVF success rates after age 40?
- What are IVF success rates after age 45?
- Should older women trigger earlier?
- Can supplements help treat ovarian aging?
- Supplements discussed: CoQ10, melatonin, myo-inositol, vitamin B, vitamin D, vitamin E, resveratrol, acetyl-L-carnitine, N-acetyl-L-cysteine, and alpha-lipoic acid.
Ovarian reserve & poor ovarian response
- What is ovarian reserve?
- What is a typical AMH level for my age?
- Can AMH levels change between tests?
- Does low AMH mean poor egg quality?
- What does very low AMH mean for my chances of IVF success?
- What is diminished ovarian reserve (DOR)?
- What treatments may help with DOR?
- Treatments discussed: DHEA, testosterone, high-dose gonadotropins, delayed-start protocols, letrozole, Clomid, growth hormone, luteal-phase stimulation, dual triggering, dual stimulation, LH supplementation, estradiol pretreatment, and corifollitropin alfa.
- Should patients with DOR trigger at smaller follicle sizes?
- Does delaying IVF treatment affect success for patients with DOR?
- Does testosterone before IVF improve outcomes for patients with DOR?
Endometriosis & adenomyosis
- Does endometriosis or adenomyosis affect IVF success rates?
- Does Lupron depot before IVF help with endometriosis?
- How common is endometriosis in unexplained infertility?
- What are some non-surgical methods to help diagnose endometriosis?
- Tests discussed: ReceptivaDx/BCL6, Endotest, DotEndo, EMScore, transvaginal ultrasound, and MRI.
- Why does endometriosis surgery not always lead to improvements in pregnancy?
Improving egg numbers & quality
- Do supplements improve egg quality?
- Supplements discussed: inositol, N-acetylcysteine (NAC), vitamin D, L-arginine, L-carnitine, CoQ10, melatonin, vitamin B complex, vitamin C, vitamin E, and combined supplements.
- How long does it take for supplements to improve egg quality?
- What are some of the problems with supplements?
- Can growth hormone (Omnitrope) improve IVF outcomes?
- Can mitochondrial donation improve egg quality?
- Can rapamycin improve egg quality?
- Can DHEA improve egg numbers or quality?
- Does the type of trigger shot affect how many eggs are retrieved?
- Triggers discussed: hCG trigger, GnRH agonist trigger, dual trigger, and double trigger.
- Can intraovarian PRP improve egg numbers or quality?
- Can follicular flushing improve egg numbers?
Lifestyle & environmental factors
- Can diet affect egg quality?
- Diets discussed: Mediterranean diet, DASH diet, vegetarian and vegan diets, ketogenic (keto) diet, and Western diet.
- Does marijuana affect egg quality?
- Does alcohol affect egg quality?
- Does sleep affect egg quality?
- Does stress affect egg quality?
- Does drinking coffee affect IVF success?
- Do endocrine disruptors affect female fertility?
- Endocrine disruptors discussed: BPA, phthalates, dioxins, pesticides, PFAS, parabens, and phenols.
- How can I reduce my exposure to endocrine disruptors?
Male Reproductive Health & Sperm Quality
Find answers about sperm quality, semen analysis, male fertility, sperm DNA fragmentation, sperm selection, lifestyle factors, and IVF outcomes.
Understanding sperm quality & semen analysis
- What does sperm quality mean?
- What does a semen analysis measure?
- What do sperm concentration, motility and morphology mean?
- What is a normal semen analysis?
- What do oligozoospermia, asthenozoospermia and teratozoospermia mean?
Sperm quality, embryos & IVF success
- Does sperm affect PGT-A euploid rates?
- What is sperm DNA fragmentation, and does it affect IVF success?
- Does PICSI help select sperm to improve success rates?
- Is Zymot helpful for selecting sperm to improve fertilization or embryo quality?
Lifestyle, supplements & sperm quality
- What do experts recommend about antioxidant supplements for male infertility?
- Which male fertility supplement brands have evidence supporting them?
- Brands discussed: Androferti, Condensyl, Cyclofert Man, Fertilaid for Men, Fertilovit Mplus, Fertimax2, FH PRO for Men, Impryl, Menevit, Profertil, Proxeed Men, Proxeed Plus, Tetrafolic, Vitascience Speramax, Gametix M, FertilHom, Ready.Set.Go!, Belimen, Men’s Fertility Support, Legacy Male Fertility Supplement, Natalist Prenatal for Him, Theralogix ConceptionXR, EU Natural Conception Men, One A Day Pre-Pregnancy Men, Baby ASAP for Men, FertilPro Men, Evolution 60, NHP Advanced Fertility Support for Men, Androenergen, Fertilmas, Andromas, Gestagyn Men, Seidiferty, and Vitafertil.
- Can too many supplements harm male fertility?
- Can diet affect sperm quality?
- Diets discussed: Mediterranean diet, DASH diet, vegetarian and vegan diets, ketogenic (keto) diet, and Western diet.
- Does male weight influence embryo quality?
- Are there any common medications that can affect male fertility?
- Do endocrine disruptors affect male fertility?
- Endocrine disruptors discussed: BPA, phthalates, dioxins, pesticides, PFAS, parabens, and phenols.
Sperm collection & use in IVF
- What happens if my partner can’t provide a sperm sample on egg retrieval day?
- Is there any difference between fresh or frozen sperm?
- Can sperm be selected to increase the chance of having a male or female embryo?
Implantation & Pregnancy Loss
Find answers about implantation failure, factors that may affect embryo transfer success, beta-hCG, recurrent pregnancy loss, immune factors, and treatments and tests used to improve implantation.
Implantation & recurrent implantation failure (RIF)
- Why do euploid embryos fail to implant or miscarry?
- What is the difference between implantation failure and miscarriage?
- How common is RIF?
- Does RIF affect success after a euploid embryo transfer?
- How likely is a live birth after euploid transfers in patients with RIF?
- Can the IVF lab affect embryo implantation and IVF success?
Factors that may affect transfer success
- Does female age affect the uterus and implantation during IVF?
- What factors affect the chance of live birth after a euploid embryo transfer?
- Does maternal age still matter when transferring a euploid?
- Does paternal age matter when transferring a euploid?
- Does a thin uterine lining reduce IVF success?
- Can uterine contractions affect IVF success?
- Does a previous C-section affect IVF success?
- How can fibroids affect implantation?
- Can small fibroids affect implantation?
- Can retained tissue after a previous miscarriage affect future implantation?
- Can silent insulin resistance affect IVF success rates?
- Does BMI affect success rates after euploid embryo transfer?
- Does the vaginal or endometrial microbiome affect IVF success?
- Does treated chronic endometritis still increase the risk of pregnancy loss after euploid transfer?
- Can embryo culture contamination cause implantation failure?
Immune system & implantation
- How does the immune system affect implantation and pregnancy?
- What are natural killer (NK) cells?
- What role do NK cells play in implantation and pregnancy?
- Can NK cells cause pregnancy loss?
Beta-hCG & early implantation
- When does implantation happen after a blastocyst transfer?
- My beta-hCG is low after embryo transfer — what are my chances of live birth?
- Does a low beta-hCG increase the risk of pregnancy complications after IVF?
- What should my beta-hCG level be after a euploid embryo transfer?
- Can a low beta-hCG after euploid transfer still result in a live birth?
Pregnancy loss & recurrent pregnancy loss (RPL)
- If I miscarried after my first embryo transfer, am I more likely to miscarry again?
- What causes RPL?
- What testing does the ASRM recommend after RPL?
- What treatments does the ASRM recommend for RPL?
- Does RPL reduce success after a euploid embryo transfer?
- What are my chances of having a live birth after multiple euploid transfers if I have RPL?
Embryo splitting, twins & multiple embryo transfer
- How often do embryos split during IVF to form twins?
- Why do embryos sometimes split and become identical twins after IVF?
- Can a single embryo split into a triplet?
- Does transferring two embryos together put one at risk?
Implantation tests
- Does the ERA improve embryo transfer success?
- Do EMMA and ALICE improve embryo transfer success?
- Does hysteroscopy before IVF improve success rates?
Treatments to improve implantation
- Do immunotherapy treatments improve IVF success?
- Immunotherapies discussed: aspirin, heparin, low-molecular-weight heparin (LMWH), corticosteroids (prednisone, prednisolone), granulocyte colony-stimulating factor (G-CSF, Neupogen, filgrastim), intralipids, intravenous immunoglobulin (IVIG), human leukemia inhibitory factor (hLIF), and peripheral blood mononuclear cells (PBMCs).
- Do probiotics before transfer help implantation?
- Can intrauterine PRP before transfer improve success rates?
- Does NK cell treatment help with infertility or IVF?
- Does endometrial scratching improve embryo transfer success?
Treatment Cycles & Transfers
Find answers about ovarian stimulation, fresh and frozen embryo transfers, FET protocols, progesterone, how many embryos to transfer, and factors around embryo transfer.
Ovarian stimulation & IVF cycles
- What does ESHRE recommend for ovarian stimulation in IVF?
- Topics discussed: AMH and AFC, ovarian stimulation protocols, gonadotropin dosing, FSH and hMG, ovarian stimulation add-ons, cycle monitoring and cancellation, trigger shots, luteal phase support, and OHSS prevention.
- Can genetic testing help choose the best type of FSH for ovarian stimulation?
- Can changing ovarian stimulation protocols help after a canceled IVF cycle?
Fresh vs frozen embryo transfer
Frozen embryo transfer (FET) protocols
- What are the different types of FET protocols?
- What is the difference between a natural and medicated FET?
- What is the difference between a true natural and modified natural FET?
- Natural or medicated FET: which is better?
- Do natural FETs have fewer pregnancy and birth complications than medicated FETs?
- How can natural FET protocols be optimized?
- Topics discussed: ovulation timing, LUF, progesterone supplementation, follicle size, endometrial thickness, estradiol, LH, and progesterone levels.
- What progesterone level is best for a medicated FET?
- Is intramuscular or vaginal progesterone better for a medicated FET?
- Is subcutaneous or intramuscular progesterone better for a medicated FET?
- How long should I wait after egg retrieval before doing an FET?
Number of embryos to transfer
- How many embryos does the ASRM recommend I transfer?
- How many embryos does ESHRE recommend I transfer?
- Why is transferring two embryos riskier than transferring one?
- Does transferring two embryos increase the chance of live birth?
- What happens when two day 3 embryos are transferred instead of one?
- How likely are twins after transferring two day 3 embryos?
- What happens when two blastocysts are transferred instead of one?
- How likely are twins after transferring two blastocysts?
Around embryo transfer
- Does EmbryoGlue improve embryo transfer success?
- Does sex around embryo transfer affect success rates?
- Does endometrial fluid before transfer affect success rates?
- Does acupuncture around embryo transfer improve embryo transfer success?
Embryology Laboratory
Find answers about IVF lab performance, embryo culture, fertilization and blastocyst rates, freezing and thawing, embryo storage, lab errors, and shipping embryos, eggs or sperm.
IVF lab performance & benchmarks
- What are good fertilization, blastocyst, thaw survival, and other IVF lab performance rates?
- Benchmarks discussed: ICSI fertilization, IVF fertilization, blastocyst formation, egg thaw survival, embryo thaw survival, and embryo biopsy success.
Embryo culture & laboratory procedures
- Is it better to culture embryos individually or in groups?
- Can embryo culture contamination cause implantation failure?
- Can eggs be missed during an IVF egg retrieval?
- How common are errors or sample mix-ups in IVF labs?
Freezing, thawing & embryo storage
Shipping embryos, eggs & sperm
- How are embryos, eggs or sperm shipped between IVF clinics?
- What should I do before shipping embryos to another clinic?
Patient Experience & Other
Find answers about the IVF experience, unexplained infertility, health and safety, IVF add-ons, and other questions that don’t fit neatly into the categories above.
IVF experience & decisions
- Does stress affect IVF success?
- Why do patients stop IVF or fertility treatment?
- How common is unassisted conception after IVF?
Health & safety
- What vaccines does ASRM recommend before or during pregnancy?
- Do children conceived through IVF have long-term health problems?
Unexplained infertility
- What is unexplained infertility?
- What does ESHRE recommend for unexplained infertility?
- Tests and treatments discussed: HSG, HyCoSy, ultrasound, hysteroscopy, laparoscopy, ovarian reserve testing, sperm DNA fragmentation testing, sperm aneuploidy testing, sperm chromatin testing, hormone testing, thyroid testing, autoimmune testing, thrombophilia testing, oxidative stress testing, genetic testing, vitamin D testing, prolactin testing, vaginal microbiome testing, IUI, IVF, ICSI, endometrial scratching, supplements, acupuncture, and inositol.
- Can unexplained infertility be linked to genetic conditions?
IVF add-ons
- Which IVF add-ons are actually supported by evidence?
- Add-ons discussed: PGT-A, endometrial scratching, EmbryoGlue, ERA, corticosteroids, PICSI, acupuncture, intralipids, intrauterine PRP, and intraovarian PRP.
- What does ESHRE recommend for IVF add-ons?
- Add-ons discussed: EmbryoGlue, AOA, artificial sperm activation, hysteroscopy, microfluidics, KIR/HLA genotyping, rescue IVM, sperm DNA fragmentation testing, PICSI, MACS, IMSI, PGT-A, non-invasive PGT, mitochondrial DNA testing, DuoStim, intravaginal/intrauterine devices, endometrial scratching, freeze-all, ERA, NK cell testing, immunotherapies, mitochondrial replacement therapy, growth factors in culture media, assisted hatching, time-lapse, intrauterine PRP, intraovarian PRP, ovarian stimulation add-ons, intrauterine hCG, intrauterine G-CSF, embryo culture media transfer, seminal plasma exposure, stem cell therapy, glucocorticoids, ICSI for non-male factor infertility, antioxidant supplements, and acupuncture.
- What do SIFES-MR, ASRM, HFEA and other organizations recommend for IVF add-ons?
- Add-ons discussed: karyotype analysis, expanded carrier screening, hysteroscopy, EmbryoGlue, corticosteroids, rescue IVM, PGT-A, ICSI, chronic endometritis testing/treatment, IMSI, endometrial scratching, ERA, time-lapse, mitochondrial DNA testing, assisted hatching, PICSI, growth hormone, DHEA, testosterone, intraovarian PRP, ovarian stem cells, MACS, microfluidics/Zymot, AOA, rescue ICSI, GM-CSF culture media, non-invasive PGT-A, microbiome testing/treatment, immune testing/treatments, intrauterine PRP, intrauterine hCG, and G-CSF.
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About Embryoman
Embryoman (Sean Lauber) is a former embryologist and the founder of Remembryo, an IVF research and fertility education website. After working in an IVF lab in the US, he returned to Canada and now focuses on making fertility research more accessible. He holds a Master’s in Immunology and launched Remembryo in 2018 to help patients and professionals make sense of IVF research. Sean shares weekly study updates on Facebook, Instagram, and Reddit regularly. He also answers questions on Reddit or in his private Facebook group.