Day 5 biopsy. One embryo at a time.
A modern IVF cycle: stimulation, egg collection, ICSI and culture to the blastocyst stage on Day 5. If you choose genetic testing (PGT-A), the biopsy is taken on Day 5 from the trophectoderm and the embryos are frozen while the results come back. A tested embryo has a higher chance of a live birth per transfer and a lower risk of miscarriage, and transferring one embryo at a time avoids almost all twin pregnancies. PGT-A is a choice, not a requirement: it does not add to the total chance of a baby from one egg collection.
In published international studies, about 50–65% of single euploid embryo transfers end in a live birth, falling only slowly with age. These are other programmes' results, not Oxford Medical's own. The chart compares them with fresh blastocyst transfer without testing, by age.
Consultant-led IVF and ICSI in Bneid Al Qar, Kuwait City, with Professor Scott Nelson and Dr Karema Alrashed: embryos cultured to Day 5 in our own laboratory, genetic testing by Day 5 biopsy when chosen, one embryo transferred at a time, and a written plan and estimate before you start.
Adjust your inputs. The percentage is the published probability of a live birth from the next embryo transfer — Franasiak 2014 and Forman 2013 for euploid single embryo transfer, SART 2022 for fresh blastocyst transfer. It is not a prediction of your own result, and not Oxford Medical's outcome data.
At your age, fresh blastocyst transfer (no PGT) gives ~37% — euploid eSET roughly doubles the per-transfer success rate.
Modern PGT-A uses next-generation sequencing (NGS) to look at all 24 chromosomes. What matters as much as the test is when the biopsy is taken and how many cells are tested. We recommend biopsy on Day 5, taking a few cells (typically 5–10) from the trophectoderm — the cells that go on to form the placenta, not the cells that become the baby. A Day 3 biopsy takes a single cell from an eight-cell embryo, and the evidence below is why we advise against it.
Same test. Different day. Different cells.
In the paired randomised trial by Scott et al (2013), embryos biopsied on Day 3 had a 39% lower sustained implantation rate than their unbiopsied pair; Day 5 trophectoderm biopsy showed no measurable effect on implantation.
About two weeks of stimulation, a short egg collection, five to six days of laboratory work and then the transfer. Whether the transfer is fresh, in the same cycle, or frozen, in a later one, is decided for each patient: freezing all embryos is needed when genetic testing is chosen and is advised when the ovaries have over-responded.
10–14 days of injectable gonadotropins (FSH ± LH). Antagonist or PPOS protocol depending on response. Monitoring scans every 2–3 days. Trigger when leading follicles reach 17–18 mm.
About 36 hours after the trigger, in our own theatre at Oxford Medical. Ultrasound-guided collection of the eggs from the ovaries, under sedation or anaesthesia, usually taking 15–30 minutes, and you go home the same day. The number of eggs depends mainly on your age and ovarian reserve (AMH and follicle count), and we discuss what to expect for you before the cycle starts.
A single sperm is injected into each mature egg under the microscope. It is used for male-factor infertility and in cycles with PGT-A, where it avoids contamination of the test by extra sperm. Typically around 70–80% of injected eggs fertilise normally.
Embryos are cultured in our own embryology laboratory, in the best modern incubators available, for five to six days until they reach the blastocyst stage (around 100–150 cells, divided into the inner cell mass and the trophectoderm). If genetic testing has been chosen, a few cells are taken on Day 5 (or Day 6 for slower embryos) from the trophectoderm — the cells that form the placenta — for NGS PGT-A. The inner cell mass, which becomes the baby, is not touched.
Embryos that are biopsied, or not transferred fresh, are vitrified (fast-frozen). In published series more than 95% of vitrified blastocysts survive warming. Freezing gives time for the genetic results to come back (usually one to two weeks) and lets the transfer take place in a later, calmer cycle.
In a later cycle the lining of the womb is prepared (natural or hormone-prepared cycle), and a single blastocyst is warmed and transferred. The transfer takes a few minutes and needs no sedation. The pregnancy test follows about 9–11 days later.
The genetic test (NGS) can be the same in both cases. What differs is when in the embryo's development the biopsy is taken, and how many cells are removed. This is why Day 5 trophectoderm biopsy is the recommended approach:
The move to Day 5 biopsy depended on reliable blastocyst culture and on vitrification, which lets embryos wait safely for their genetic results. Both have been routine in IVF laboratories since the mid-2010s.
Patients sometimes ask for two embryos to increase the chance of pregnancy in one cycle. When the embryo has been tested, the gain is small: in published studies a single euploid blastocyst leads to a live birth in about 50–65% of transfers, and a second embryo adds a little to the chance in that cycle — at the cost of a much higher chance of twins.
Preterm birth, low birth weight, pre-eclampsia, gestational diabetes and admission to the neonatal unit are all several times more common in twin pregnancies. Twins are not a bonus; they are a higher-risk pregnancy.
In the randomised trial by Forman et al (2013), transferring one euploid blastocyst gave the same ongoing pregnancy rate as transferring two untested blastocysts, with almost no twins. Transferring tested embryos one at a time, over two transfers if needed, gives a similar overall chance of a baby to transferring two together, without the twin risk.
When a twin pregnancy goes wrong, the alternatives — selective reduction, monoamniotic complications, severe pre-term — are difficult clinically and emotionally. Avoiding the situation is better than managing it.
We discuss exceptions case by case — for example women with few embryos, older women, or repeated implantation failure. The default is a single embryo; the decision is individual.
IVF is not the first answer for most fertility cases — it's the right answer for specific ones. The first consultation is a 30-minute review to decide whether you actually need it.
Day 3 biopsy was standard before vitrification became reliable, because the genetic result had to come back in time for a fresh transfer. Once embryos could be frozen and warmed safely, most laboratories moved to Day 5 biopsy. Some patients still ask for Day 3 testing; we explain the evidence above and recommend Day 5.
In the Scott et al (2013) paired randomised trial, Day 5 trophectoderm biopsy had no measurable effect on implantation compared with unbiopsied embryos. The biopsy takes cells from the placenta lineage, not from the inner cell mass that becomes the baby. Follow-up of children born after embryo biopsy has so far been reassuring, although the long-term studies are still relatively small.
The chance of a live birth from transferring one euploid embryo (about 50–65% in published studies) is much the same whether it is your only euploid embryo or one of several. The number of embryos changes your overall chance across several attempts, and what remains for future siblings, not the chance of each transfer.
It happens — particularly in women over 40, where the proportion of euploid embryos falls sharply. The usual next step is another stimulation cycle, sometimes with a different protocol; for some women, collecting embryos over two or three cycles before any transfer is the right plan. Supplements have not been shown to improve egg quality reliably. We discuss this honestly at consultation; the decision depends on your ovarian reserve and how you responded before.
Always when PGT-A is chosen, because the transfer has to wait for the genetic results, and when the ovaries have over-responded, because freezing all embryos lowers the risk of ovarian hyperstimulation syndrome. For other women, large randomised trials show that a fresh transfer gives a similar chance of a baby, so the choice is made individually. Vitrified blastocysts survive warming in more than 95% of cases in published series.
It's a conversation, not a default. Twin pregnancy raises the risk of preterm birth, low birth weight, pre-eclampsia, gestational diabetes and neonatal unit admission several-fold compared with a singleton pregnancy. Transferring tested embryos one at a time gives a similar overall chance of a baby to transferring two together, without the twin risk. Exceptions exist — older age, very few embryos, repeated implantation failure — and those decisions are made case by case.
The cost depends mainly on the medication doses you need and on what the cycle includes — for example a fresh transfer, freezing, or genetic testing. Monitoring is paid visit by visit, and the main payment is made on the day of egg collection. We give you a written estimate for your own plan at consultation, once we know your AMH and ovarian reserve.
It depends on your age and ovarian reserve. Women under 35 with a normal AMH often have enough euploid embryos from one stimulation cycle for more than one transfer. Women in their late 30s more often need a second cycle, and women over 42 may need several cycles to obtain a single euploid blastocyst — and some will not. The calculator above gives the published averages for your age; we tailor the estimate at consultation.
The page comes down to four figures, each from the published literature rather than our own outcome data.
Whether IVF is right for you, what protocol fits your reserve, what the cycle looks like, what it will cost. We'll go through your AMH, ultrasound, semen analysis if available, and prior workup. The decision is made together.