3 Discussion
The definition of a premature LH surge differs depending on the study.
In our case, if the definition of Kummer et al.5 (LH
levels ≥ 10 mIU/mL and > 50% rise from baseline) was used,
an accurate premature LH surge or ovulation could not be predicted or
specified. Therefore, the spontaneous ovulation date of our case was
estimated from two parameters, the GS and crown-rump length (CRL). If a
10-mm GS is detected at 11 days after the OPU and that day is defined as
a menstrual age of 40 days6, the estimated ovulation
date is CD 9. The CRL was 15 mm 28 days after the OPU, and the estimated
gestational age was 7 weeks+4, 8 weeks+2, and 9 weeks by 5, 50, and 95
percentile, respectively. Therefore, the estimated ovulation date was CD
8 (3–13)6.
Because the natural menstrual cycle in our case was 28 days, this
suggested that ovulation might have occurred earlier than it should have
in a natural cycle.
If normal COS is in progress, early luteinization and follicular atresia
will occur after a premature LH surge7. However, in
our case, fertilization and implantation occurred after the presumed
spontaneous ovulation day, and follicular development was observed after
this time. A total of 31 oocytes were retrieved by using a GnRH agonist
trigger.
A previous study reported that the outcome of luteal phase ovarian
stimulation (LU) was higher than that for follicular phase ovarian
stimulation (FO) regarding the total dosage of hMG, M2
rate7, number of oocytes collected, fertilization
rate, and the number of day 3 embryos8. Additionally,
a study that compared FO only to FO + LU reported that the FO + LU group
had a higher number of retrieved oocytes, M2 rate, and 2 PN
rate9. Theoretically, continued stimulation after
spontaneous ovulation is therefore possible for retrieving oocytes.
Although good results are obtained with LU, in this case, as a result of
ICSI performed on 21 M2 oocytes in our case, 12 of 21 had 2 PN, but 5
had 3 PN. Higher peak estradiol levels, large oocyte yields, a high
gonadotropin dose, and a lengthy stimulation procedure are considered to
increase 3 PN10,11. Therefore, additional attention
should be paid to stimulation after spontaneous ovulation.