Researchers in a 2026 study found that natural FETs using donor eggs were linked to higher live birth rates, lower miscarriage rates, and lower rates of some pregnancy complications compared to medicated FETs.

For a frozen embryo transfer, the uterine lining can be prepared using the body’s own hormones (natural FET) or with estrogen and progesterone medications (medicated FET).

A study by Rafael et al. (2026) looked at more than 67,000 donor egg transfers. Donor eggs were used to help control for egg quality differences, which can strongly affect IVF success rates and make these comparisons harder to interpret.

The researchers found better outcomes with natural FETs, and age didn’t appear to change the results.

One possible reason is the corpus luteum, which is present in natural FETs but absent in medicated FETs. It produces factors that help support implantation and placental development during early pregnancy.

The researchers also found that natural FETs still performed better even when medicated cycles used progesterone monitoring and “rescue” progesterone to correct low levels.

Overall, this study adds to growing evidence that natural FETs may provide a more beneficial environment for implantation and pregnancy, while also reducing complications.

✅ Check out the details on Remembryo: https://www.remembryo.com/natural-fets-outperform-medicated-fets-in-donor-egg-cycles/

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

The Uterine Wall of Fame (UWOF) is a collection of real IVF success stories from people who faced tough odds -- low-grade embryos, repeated failures, low AMH, mosaic results, and more. 

UWOF #38 is one of those stories! Six retrievals and seven embryo transfers were needed before a Day 6 4BB euploid embryo finally led to a healthy baby at age 40, after an early euploid rate of just 1 out of 17 embryos.

✅ Visit the UWOF to read this story and others like it (free to access & no subscription required): https://www.remembryo.com/uwof-38-low-euploid-rate-7-transfers-and-a-baby-at-40/

💌 Have a story of your own? Can be anonymous or named: https://www.remembryo.com/uterine-wall-of-fame-submission-form/

⚠️ The UWOF is a project by Remembryo / Embryoman, created to give hope to others going through IVF with challenging situations. These stories are personal, not medical advice. A success story does not prove a specific treatment caused the outcome – always discuss decisions with your doctor.

PGT-A involves removing a few cells from the embryo before transfer to test for chromosome abnormalities.

Because these cells come from the part of the embryo that later becomes the placenta, some researchers have questioned whether PGT-A could affect pregnancy or newborn outcomes.

In this meta-analysis, Hyttel et al. (2026) combined the results of 12 studies involving more than 56,000 live births after IVF/ICSI. They found no increase in risks like preeclampsia, preterm birth, low birth weight, or babies being small for gestational age in pregnancies after PGT-A compared to IVF/ICSI without PGT-A.

Limitations: Most of the included studies were retrospective, and some complications were rare, making them harder to study.

✅ This post is a quick look at one study, rather than a full breakdown on Remembryo. Link to the study is here: https://academic.oup.com/humrep/advance-article-abstract/doi/10.1093/humrep/deag049/8650374?redirectedFrom=fulltext

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

PRP, or ovarian rejuvenation, is becoming popular in IVF, especially for patients with low ovarian reserve or poor response. 

Platelet-rich plasma (PRP) is made from a patient’s own blood. The blood is processed to concentrate platelets, which contain growth factors and signaling molecules, and the PRP is then injected into the ovaries with the goal of improving the ovarian environment and ovarian function.

A new study by Wang et al. (2026) performed a meta-analysis to combine the results of 19 prospective studies on PRP, including two randomized trials.

Overall, they found improvements in AMH, AFC, egg numbers and the number of transferrable embryos. When looking only at randomized trials (higher quality studies), one study found a small increase in egg numbers, and both found no differences in blastocyst formation rates or live birth rates.

The authors concluded that PRP should still be considered experimental, and that larger, better-designed randomized trials are needed before it can be recommended routinely.

Limitations: The studies used different PRP preparation and injection protocols, included patients with varying ages and ovarian reserve, and many lacked control groups, making the results harder to compare and interpret.

✅ This post is a quick look at one study, rather than a full breakdown on Remembryo. Full study is here: https://www.mdpi.com/2077-0383/15/7/2482

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

Aneuploid embryo success rates after transfer are very low, with about 1% leading to a live birth, likely due to undetected mosaicism after PGT-A rather than true whole chromosome aneuploidy.

This refers specifically to whole chromosome aneuploids (missing or extra full chromosomes), not segmental aneuploids. All studies below used NGS-based PGT-A.

Embryos labeled as aneuploid by PGT-A are usually not transferred, based on the assumption that they won’t lead to a successful pregnancy.

There’s limited research on transferring these embryos, but key studies include:

• Tiegs et al. (2021): 0/102 live births
• Wang et al. (2021): 2/44 live births
• Barad et al. (2022): 0/84 live births
• Tise et al. (2025): at least 1 (possibly 2) from 3 embryos
• Madjunkov et al. (2026): 0/70 live births

So most aneuploids either do not implant or miscarry.

Then how do rare successes happen?

A few possible explanations:

• The embryo is actually mosaic but the biopsy missed normal cells
• PGT-A limitations (thresholds, noise)
• Rare issues like DNA contamination, mix-ups, or unassisted conception around the time of transfer

✅ Check out the details on Remembryo: https://www.remembryo.com/aneuploid-embryo-success-rates/

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

Egg donation is commonly used for older patients or those with low ovarian reserve, but it may come with different risks.

In this large meta-analysis, van Bentem et al. (2026) combined individual patient data from 16 studies, and found that donor egg pregnancies had about a 2 to 3× higher risk of hypertensive complications like preeclampsia compared to both IVF with own eggs and unassisted pregnancies, even after accounting for factors like age and twins.

This higher risk was seen across many groups (age, BMI, twins, etc.), suggesting egg donation itself may play a role, although factors like older age, obesity, and twin pregnancy can add to the risk.

One possible explanation is the immune system, since the embryo is less genetically similar to the patient. Similar patterns are seen in first pregnancies, donor sperm, and surrogacy.

There were hints that aspirin or blood thinners might lower risk, but the data were mixed.

Limitations: This was observational data, and some details were missing (like donor information and transfer protocols), so it can’t show cause and effect.

✅ This post is a quick look at one study, rather than a full breakdown on Remembryo. Full study is here: https://academic.oup.com/humupd/advance-article/doi/10.1093/humupd/dmag006/8566487?login=false

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

April’s IVF Research Roundup is live!

🔹 New study highlights

🔹 IVF news & community Q&A

🔹 ~50 research study summaries (subscribers only)

📌 Post is free to read (no paywall): https://www.remembryo.com/monthly-ivf-research-roundup-april-2026/

A new study found that bacteria detected on the embryo transfer catheter were linked to lower live birth rates, likely reflecting the patient’s own microbiome being carried into the uterus during transfer.

During embryo transfer, the catheter passes through the vagina and cervix, which are not sterile, meaning bacteria can be carried into the uterus and this may affect implantation.

A study by Boughanmi et al. (2026) measured bacteria in the vagina, cervix, and on the catheter after transfer, and compared this to pregnancy outcomes.

They found that when certain bacteria were present, live birth rates were much lower, while patients with more Lactobacillus had better outcomes. These bacteria were more common in patients with bacterial vaginosis (BV), a common and often unrecognized imbalance of the vaginal microbiome.

This suggests that the embryo transfer procedure itself may carry bacteria into the uterus, and that differences in the vaginal microbiome could quietly affect success rates.

The authors highlight BV as important, noting it can be screened for with a simple test. However, the study didn’t test whether treating BV or changing the microbiome improves outcomes, so this still needs to be confirmed.

✅ Check out the details on Remembryo: https://www.remembryo.com/bacteria-on-the-embryo-transfer-catheter-linked-to-lower-live-birth-rates/

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

After an unsuccessful first transfer or pregnancy loss, it’s common to worry that something is wrong and will happen again.

In a study by Barrett and colleagues, outcomes in the second euploid transfer were very similar, no matter what happened in the first:

• Live birth rates stayed consistent (~54–59%)

• The chance of a "no pregnancy" result was similar (~21–23%)

• Miscarriage rates didn’t increase

In other words, whether the first transfer resulted in:

– no pregnancy

– a biochemical loss

– or a clinical miscarriage

it didn’t affect the chances of success in the next transfer.

This was for euploids, but they also found similar results for untested embryos.

This suggests that a single unsuccessful first transfer or early loss doesn’t necessarily signal an underlying issue that will repeat.

Important: This study looked at first to second transfers only, and included patients around age 35, so it doesn’t apply to all situations (like recurrent implantation failure or recurrent pregnancy loss).

✅ Check out the details on Remembryo: https://www.remembryo.com/a-pregnancy-loss-in-the-first-transfer-does-not-increase-risk-in-the-next/

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

Most clinics transfer day 5 embryos after 5 or 6 days of progesterone in a medicated frozen embryo transfer (FET). But for day 6 embryos, it’s less clear what the timing should be, so a randomized trial tested whether 6 or 7 days of progesterone works better.

Live birth rates were similar (45.0% vs 40.2%), with no differences in pregnancy, miscarriage, or complications like preterm birth or hypertensive disorders of pregnancy.

This was a single-center study and wasn’t designed to detect small differences between groups, so a smaller difference between live birth rates could have been missed. Overall, both timings performed similarly, suggesting some flexibility in how day 6 embryos are scheduled.

✅ This post is a quick look at one study, rather than a full breakdown. Full study: https://academic.oup.com/hropen/article/2026/2/hoag023/8525333

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

A new study found that infertility is traumatic for some patients, with 9% meeting criteria for PTSD and 32% for complex PTSD, and patient narratives highlight distress, loss of control, and gaps in care.

Infertility is often described as “stressful,” but for some, it can feel more like trauma, affecting a sense of control, identity, and safety. Sofia Gameiro and colleagues (PMID: 41818724) surveyed patients in the UK and Ireland and assessed PTSD symptoms while also analyzing patient experiences.

Patients who met criteria for PTSD/complex PTSD tended to have more recent and difficult journeys, including failed treatment or miscarriage. 

• 61% said aspects of IVF care made things worse

• 26.8% were offered support

• Only 15.9% said trauma was discussed by their care team 

The carousel shares some of the patient quotes, which I think are the most impactful part of the study.

Patients also highlighted ways care could improve, including better support and more awareness of trauma. That said, the patients surveyed may overrepresent those with more distressing experiences, and some groups were underrepresented, so results may not apply to all patients.

✅ Check out the details on Remembryo. 𝐍𝐨 𝐩𝐚𝐲𝐰𝐚𝐥𝐥 𝐨𝐧 𝐭𝐡𝐢𝐬 𝐩𝐨𝐬𝐭 𝐟𝐨𝐫 𝐍𝐚𝐭𝐢𝐨𝐧𝐚𝐥 𝐈𝐧𝐟𝐞𝐫𝐭𝐢𝐥𝐢𝐭𝐲 𝐀𝐰𝐚𝐫𝐞𝐧𝐞𝐬𝐬 𝐖𝐞𝐞𝐤. https://www.remembryo.com/about-4-in-10-ivf-patients-meet-criteria-for-ptsd-or-complex-ptsd/

✉️ Like this post? Get a free weekly summary of the latest IVF research: https://mailchi.mp/remembryo/x27kx5o1sw

The Uterine Wall of Fame (UWOF) is a collection of real IVF success stories from people who faced tough odds -- low-grade embryos, repeated failures, low AMH, mosaic results, and more. They are shared for support and perspective, not as evidence that a specific treatment works.

UWOF #36 is one of those stories!

After 18 years of infertility, 6 retrievals, and more than 50 embryos arresting at day 3, Dina conceived at 41 from four frozen day 3 embryos. She delivered a healthy baby boy at 42.

✅ Visit the UWOF to read this full story and others like it (free to access & no subscription required): https://www.remembryo.com/uwof-36-over-50-embryos-arrested-one-day-3-baby-at-42/

💌 Have a story of your own? Can be anonymous or named: https://www.remembryo.com/uterine-wall-of-fame-submission-form/

⚠️ The UWOF is a project by Remembryo / Embryoman, created to give hope to others going through IVF with challenging situations. These stories are personal, not medical advice. A success story does not prove a specific treatment caused the outcome—always discuss decisions with your doctor.