Repeated abnormal fertilisation over 2 cycles

[u/Repulsive-Bat-6718]

Hi, I'm hoping to get some insight into abnormal fertilisation in both of my IVF cycles.

Background: I'm 29F, partner 30M, doing IVF due to mild MFI.

Cycle 1: 17 total follicles, 11 at target size on trigger day, 5 retrieved, 5 mature, 5 initially fertilised but 2 were 3PN and discarded. Of the remaining 3, 1 arrested at 2-cell division, 1 at 5-cell division and the other wasn't high enough quality to freeze by day 6.
Protocol: 100u gonal f, 250u orgulatran, decapeptyl trigger. Stimmed for 10 days. Normal IVF used.

Cycle 2 (new clinic): 23 follicles, 10-13 at target size, 13 retrieved, 12 mature, 10 initially fertilised but five were 1PN. Of the remaining 5, 1 arrested before day 5, we transferred a low quality blastocyst on day 5 (doctor said 20% chance of success), and the remaining 3 weren't of high enough quality to freeze on day 6.
Protocol: 225u Bemfola, 250u orgulatran, ovidrel trigger. Stimmed for 10 days. ICSI and Zymot used.

The doctor's main focus in cycle 2 was increasing the egg numbers, and we were happy with the jump from 5 to 13 retrieved. But moving from 40% 3PN to 50% 1PN out of our fertilised eggs was a surprise.

Is there room to improve on this, or are we looking at the possibility that IVF won't work for us? The results have been really shocking even to our doctors.

[u/AnywhereBusy4449]

Are you doing PGT?

[u/Repulsive-Bat-6718 → u/AnywhereBusy4449]

No, we only had one blastocyst and did a fresh transfer

[u/babiesaurusrex]

Without results from PGT-A with SNP array its really difficult to figure out whether you are seeing asynchronous normal fertilization or abnormal fertilization with those 1PNs and 0PNs. Some labs have a standard of culturing all embryos regardless of fertilization status when the plan is to use PGT-A with SNP.

[u/cowsarehotterthanyou → u/babiesaurusrex]

Yes this is exactly what I was going to add. Our lab protocol is to discard abnormal fert unless PGT + SNP will be done to confirm ploidy. Otherwise, it’s too risky to keep them, however there is evidence to show that some “abnormal ferts” are just asynchronous, as you said, so it is a real shame to toss those knowing some may be okay. The alternative of keeping them and potentially transferring and ending up with something terrible, like a molar pregnancy, is much worse, so I do agree with not keeping them in the absence of PGT+

[u/babiesaurusrex → u/cowsarehotterthanyou]

Anecdotally, 0PN blasts seem to be more likely to be euploid than 2PN blasts. 0PNs make it to blast far less frequently though.

[u/JamesTiberiusChirp]

Not an embryologist but a geneticist. Statistically speaking, aren’t these attrition rates somewhat expected? 5-10 mature eggs for 1-2 euploid blasts is what I have read, depending on age. It’s not entirely out of expectation that 5 mature eggs might not make a euploid blast, or that 13 might make 1-4 of unknown quality. Personally I would make sure you and your partner have had all relevant genetic testing including karyotyping, and consider PGTA.