Frozen Embryo Transfer (FET) Hyderabad | FET IVF Success Rate

Q: What is frozen embryo transfer (FET)?

Frozen embryo transfer (FET) is an IVF procedure where embryos created during a previous egg retrieval cycle are thawed and transferred into the uterus during a subsequent, carefully prepared cycle. The embryos are stored in liquid nitrogen (-196°C) and can remain viable for many years. FET has become the preferred method at most IVF centres because success rates are equal to or better than fresh transfers, with lower risk of ovarian hyperstimulation syndrome (OHSS) and better uterine preparation.

Q: Is frozen embryo transfer better than fresh IVF transfer?

In many cases, yes. Studies show FET success rates are equal to or higher than fresh transfers. Reasons: (1) The uterine lining is not affected by the high oestrogen levels of the stimulation cycle, making it more receptive. (2) No OHSS risk. (3) Embryos can be transferred in a natural or medicated cycle at the optimal time. (4) PGT-A genetic testing of embryos (to select normal ones) requires freezing — then FET. For women with PCOS or risk of OHSS, freeze-all + FET is the safest and most effective protocol.

Q: How is frozen embryo transfer done step by step?

FET involves: (1) Lining preparation — either natural (waiting for ovulation) or medicated (oestrogen tablets for 10–14 days to grow the lining to 8mm+). (2) Progesterone start — vaginal or oral progesterone is started to prepare the lining for implantation. (3) Transfer day — typically 5 days after progesterone start for blastocyst-stage embryos. The thawed embryo is placed inside the uterus through a thin catheter under ultrasound guidance. It takes 15–20 minutes and is usually painless. (4) Post-transfer support — progesterone continued for 10–12 weeks if pregnancy is confirmed. Pregnancy test at day 12–14 after transfer.

Q: What is the success rate of frozen embryo transfer in Hyderabad?

At Mother Hospitals Boduppal, FET success rates (live birth per transfer) for women under 35 with good quality blastocysts range from 45–60%. For women 35–40, rates are 30–45% per transfer. When PGT-A tested (chromosomally normal) embryos are transferred, success rates improve further — miscarriage rates drop below 10% per cycle. Success depends on embryo quality, woman's age at egg retrieval, endometrial lining quality, and whether PGT-A was performed.

Q: How long can embryos be frozen?

Embryos can be stored frozen for many years without significant loss of viability. Studies show embryos frozen for 10 years have similar success rates to those frozen for 1 year. In India, the ART Act 2021 currently limits embryo storage to 5 years (extendable by mutual consent). At Mother Hospitals, all embryos are stored in advanced vitrification systems (ultra-rapid freezing) that preserve embryo quality optimally, with survival rates above 95% on thawing.

Q: What should I do to prepare for frozen embryo transfer?

To prepare for FET: take prescribed oestrogen tablets as directed to build the lining, attend ultrasound scans on scheduled days (usually day 2, day 8–10, and day 12–14 of the preparation cycle), avoid strenuous exercise and heavy lifting, maintain hydration, avoid alcohol and smoking, take folic acid 5 mg daily, keep vitamin D3 and B12 optimised, attend acupuncture (optional but may help), and most importantly — rest but do not be completely sedentary after transfer. Walking is fine. The transfer itself is simple and painless — no anaesthesia required.

95%+

Embryo survival rate after vitrification (thawing)

45–60%

Live birth rate per FET (women under 35)

10 yrs

Frozen embryos remain viable for — no quality loss

0

OHSS risk with freeze-all FET protocol

What Is a Frozen Embryo Transfer (FET)?

In a standard IVF cycle, eggs are retrieved, fertilised in the lab, and embryos are grown for 3–5 days. Instead of transferring the embryo immediately (fresh transfer), the embryo is frozen and stored — then transferred in a separate, prepared cycle. This is called a Frozen Embryo Transfer or FET.

Why FET has replaced fresh transfer as the default: During an egg retrieval cycle, high oestrogen levels from stimulation drugs make the uterine lining less receptive. Freezing the embryo and doing the transfer in a separate "calm" cycle — when the lining is optimally prepared — leads to better implantation. This shift happened over the last 10 years as vitrification technology improved dramatically.

✅ Advantages of FET over Fresh Transfer

Uterine lining is more receptive — not affected by stimulation drugs
No risk of OHSS (ovarian hyperstimulation syndrome)
Allows time for PGT-A genetic testing of embryos before transfer
Flexible timing — transfer in any suitable cycle
Better safety for PCOS patients (mandatory freeze-all)
Equal or better pregnancy rates vs fresh transfer
Time to optimise lining, treat any infection, or correct uterine issue

📋 Who needs FET?

All PCOS patients (to prevent OHSS — freeze-all is mandatory)
Anyone who had PGT-A genetic testing of embryos
Patients who had a thin lining on fresh transfer day
Patients with elevated progesterone on egg retrieval day
Anyone who retrieved many eggs (OHSS risk)
Patients with extra embryos from a previous cycle
Women who want to preserve embryos and plan transfer later

FET Step by Step — Your Timeline at Mother Hospitals

A standard medicated FET cycle takes approximately 3–4 weeks from the first day of your period to embryo transfer:

Day 1–2 of your period — Baseline scan

Pelvic ultrasound to check that ovaries are quiet and the uterine lining has shed properly. Blood oestrogen level checked. Oestrogen tablets (oestradiol valerate) are prescribed — usually 2 mg twice daily to start.
Day 8–10 — First lining scan

Ultrasound to measure endometrial thickness and pattern. We are looking for a triple-line pattern and thickness of at least 7–8 mm. Dose of oestrogen adjusted if needed.
Day 12–14 — Second lining scan + progesterone start

Lining confirmed at 8 mm or above. Progesterone (vaginal pessaries or gel) is started. This is called "P+5" countdown — transfer will happen 5 days after progesterone begins (for blastocyst transfer).
P+5 (approximately Day 17–20) — Embryo Transfer Day

The frozen embryo is carefully thawed in the lab — this takes 1–2 hours and the embryologist confirms it has survived (95%+ survival with vitrification). Under ultrasound guidance, the embryo is placed into the uterus through a thin, soft catheter. The procedure takes 15–20 minutes. You will be asked to rest briefly before going home.
P+5 to P+14 — Two Week Wait

Continue oestrogen and progesterone as prescribed. Light activity is fine — walking is encouraged. Avoid hot baths, heavy lifting, strenuous exercise. No sexual intercourse during this period. Your blood hCG pregnancy test is done exactly 14 days after progesterone start.
P+14 — Pregnancy Test (hCG blood test)

A blood beta-hCG level above 50–100 IU/L confirms pregnancy. If positive, medications continue until 10–12 weeks of pregnancy. First ultrasound scan is scheduled at 6–7 weeks to confirm fetal heartbeat.

"The FET was so much easier than the retrieval cycle. I barely felt anything during the transfer. It was like a routine internal scan."
This is one of the most common reactions from our patients at Mother Hospitals after their FET. Unlike the egg retrieval (which requires sedation and is more involved), the embryo transfer is gentle, quick, and almost always painless.

What Affects FET Success Rate in Hyderabad?

Not all FET cycles are equal. Here are the key factors that determine whether your frozen embryo transfer succeeds:

🌟 Factors that improve FET success

Blastocyst-stage embryo (Day 5) — higher success than Day 3
PGT-A tested embryo — normal chromosomes confirmed
Endometrial lining 8 mm or above with triple-line pattern
Personalised transfer using ERA test (optimal implantation window)
Treated uterine infections (ALICE test result positive → treated)
Good progesterone levels on transfer day
Woman age under 35 at egg retrieval
Non-smoker, healthy weight, good vitamin D3 levels

⚠️ Factors that can reduce FET success

Thin endometrial lining (under 7 mm) — needs optimisation
Chromosomally abnormal embryo (if PGT-A not done)
Uterine polyp or septum — must be treated before transfer
Elevated NK cells — immune factors reducing implantation
Chronic endometritis (uterine infection) — silent, needs ALICE test
Progesterone too high or too low on transfer day
Advanced maternal age (egg quality declines from 37+)
Smoking, high BMI, uncontrolled thyroid disease

      Optimising Your FET at Mother Hospitals
      Thyroid check before starting — TSH must be below 2.5 for FET
Vitamin D3 and B12 levels optimised — deficiency reduces implantation
Lining assessed with 3D ultrasound — not just standard 2D
Progesterone blood level confirmed on day of transfer
ERA test offered for patients with 2+ failed transfers
EMMA/ALICE test for microbiome and infection assessment when indicated
Scratch procedure (endometrial receptivity scratching) when beneficial
Post-transfer care: light walking, avoid NSAID painkillers, continue luteal support

    

Dr. Prashanthi Reddy

MD (OBG) · Fertility & IVF Specialist · TGMC Reg: 50624
19+ years of IVF practice. Specialises in freeze-all protocols, personalised FET using ERA, and PGT-A embryo testing. Every FET at Mother Hospitals is individually planned — no one-size approach.
IVF Clinic: Monday–Saturday · Call 97059 93366 or WhatsApp 97059 93355

Frequently Asked Questions — Frozen Embryo Transfer

What is frozen embryo transfer (FET)?

Frozen embryo transfer (FET) is a procedure where embryos created during a previous IVF egg retrieval are thawed and transferred into the uterus during a separately prepared cycle. Embryos are stored in liquid nitrogen at -196°C and can remain viable for many years. FET has become the standard method at most leading IVF centres because success rates equal or exceed fresh transfers, with better uterine preparation and no OHSS risk.

Is frozen embryo transfer better than fresh IVF transfer?

In most cases, yes. FET offers a more receptive uterine lining (not affected by stimulation hormones), no OHSS risk, and the ability to do PGT-A genetic testing before transfer. Multiple large studies show similar or higher live birth rates with FET vs fresh transfer. For PCOS patients, freeze-all + FET is mandatory — fresh transfer carries significant OHSS risk in this group. Even for normal responders, freeze-all FET is increasingly preferred.

How is frozen embryo transfer done step by step?

The FET preparation cycle: (1) Start oestrogen tablets from Day 1–2 of your period. (2) Ultrasound scan on Day 8–10 to check lining thickness. (3) When lining reaches 8 mm+ with triple-line pattern, progesterone is started. (4) Five days after progesterone start, the blastocyst embryo is thawed and transferred. The transfer takes 15–20 minutes under ultrasound guidance with no anaesthesia needed. (5) Pregnancy blood test 14 days after progesterone start. Medications continue until 10–12 weeks if positive.

What is the success rate of frozen embryo transfer in Hyderabad?

At Mother Hospitals Boduppal, live birth rates per FET for women under 35 with good quality blastocysts are 45–60%. For women 35–40, rates are 30–45% per transfer. With PGT-A tested (chromosomally normal) embryos, success rates improve further and miscarriage rates drop below 10%. The most important factors are embryo quality, woman's age at egg retrieval, and endometrial lining quality at transfer.

How long can embryos be frozen?

Embryos stored using vitrification (ultra-rapid freezing) remain viable for many years without loss of quality. Studies show embryos frozen for 10 years have similar success rates to those frozen for 1 year. The freezing process — not storage time — is the critical moment. At Mother Hospitals, our vitrification system achieves 95%+ embryo survival on thawing. In India, the ART Act 2021 currently governs storage duration — typically 5 years with options for extension.

What should I do to prepare for frozen embryo transfer?

Preparation for FET: take oestrogen tablets as prescribed, attend all scan appointments, optimise thyroid (TSH below 2.5), ensure vitamin D3 and B12 are adequate, take folic acid 5 mg daily, avoid smoking and alcohol, maintain light exercise (walking is ideal), avoid NSAID painkillers (aspirin protocol exceptions aside), and stay hydrated. After transfer: rest briefly at the clinic, light walking at home is encouraged (bed rest is not necessary), avoid heavy lifting and hot baths. Pregnancy test at day 14 — not before, as early testing can be misleading.

Frozen Embryo Transfer (FET) — What It Is, How It Works, and Why It Is Now Preferred Over Fresh IVF