Study Design
This retrospective study included women who underwent IUI with donor
sperm in a natural menstrual cycle. The trial was conducted between
January 2012 and December 2017 at the Center for Reproductive Medicine
of the Shandong Provincial Hospital Affiliated to Shandong University.
The Institutional Review Board approved the research project.
Prior to the IUI cycles, all women underwent basic fertility
investigation that included evaluations of the following: cycle day 3
FSH, LH, estradiol, anti-Müllerian hormone (AMH), prolactin, and thyroid
stimulating hormone (TSH) levels, hysterosonography (at least one month
prior to IUI), as well as transvaginal ultrasound for evaluation of
pelvic anatomy and follicular monitoring.
Study inclusion criteria were: age ≤ 35 years, regular menstrual cycles
(28–35 days), no personal history of infertility or medical conditions
likely to cause infertility, a normal baseline hormonal profile, and
patency of at least one fallopian tube. Exclusion criteria were the
presence of irregular menstrual cycles, tubal factor infertility,
confirmed endometriosis, a diagnosis of polycystic ovarian syndrome
(according to the Rotterdam criteria; Rotterdam ESHRE/ASRM-Sponsored
PCOS Consensus Workshop Group, 2004), abnormal TSH or prolactin levels,
or any known metabolic or endocrinological disease. Women with
incomplete medical records were excluded from the study, as were women
who taking any medication.
The choice to use hCG trigger or urinary LH monitoring plus transvaginal
ultrasonography was made according to the patient’s preference and
availability for monitoring. A home urinary ovulation prediction kit was
used to monitor urinary LH levels once a day, in the evening around
19:00 h, starting on cycle day 10. And serial ultrasonography for
follicular monitoring was also started on cycle day 10 for all cycles.
When ovulation was diagnosed, insemination was performed immediately.
In the spontaneous ovulation group (based on urinary LH monitoring and
transvaginal ultrasonography), insemination was carried out within 24
hours after detection of the first urinary LH positive test or upon
detection of ultrasound features suggestive of ovulation. In the induced
ovulation group (administration of hCG trigger), when a leading follicle
reached a diameter of 16 mm or urinary LH surge appeared, ovulation was
triggered using 10,000 IU of recombinant hCG (choriogonadotropin alfa,
Ovidrel®; EMD Serono, Inc.). In our practice, the standard of care is to
perform two inseminations in a given cycle, approximately 24 hours and
36 hours after HCG injection 13-15; however, there are
clinical factors affecting the clinical decision to use single or double
IUI including patient demand, financial barriers, or ovulation time.
Frozen donor sperm were obtained from the Shandong Province Human Sperm
Bank of China, and were thawed on site on the day of insemination. All
sperm samples were prepared with a density gradient centrifugation
method using Puresperm TM (Nidacon, International AB)16. The quality of semen was evaluated before and
after processing (semen TMS).
The insemination procedure was the same for all women, bed rest was
maintained for 15 min after the insemination 17. A
urine pregnancy test was administered 14 days after insemination, and if
positive, a transvaginal ultrasound would be performed 14 days later to
assess the pregnancy outcome (including the number of gestational sacs,
viability, and location).