Reproductive · Year 2 · from Reproductive
Case 3: In Vitro Fertilization for Unexplained Infertility
Clinical Image
Source: Wikipedia - In vitro fertilisation - CC BY-SA 4.0
Case Presentation
A 36-year-old G0 woman and her 38-year-old husband present after 2 years of infertility. Complete evaluation reveals: regular ovulatory cycles confirmed by mid-luteal progesterone of 14 ng/mL, normal ovarian reserve (AMH 2.2 ng/mL, day 3 FSH 8 mIU/mL, AFC 12), patent fallopian tubes on HSG, normal uterine cavity, and normal semen analysis. No cause for their infertility is identified. The diagnosis is unexplained infertility. They have already tried 3 cycles of ovulation induction with letrozole plus timed intercourse and 3 cycles of letrozole plus intrauterine insemination (IUI) without success. Given her age (36 years) and the duration of infertility, they are counseled that IVF offers the highest per-cycle success rate. They proceed with IVF. She undergoes controlled ovarian hyperstimulation with gonadotropins. Fifteen oocytes are retrieved. Twelve are mature, and 10 fertilize normally with conventional insemination. Five blastocysts develop by day 5. Preimplantation genetic testing for aneuploidy (PGT-A) reveals 3 euploid embryos. A single euploid blastocyst is transferred, and she conceives. She delivers a healthy infant at 39 weeks. The remaining 2 euploid embryos are cryopreserved for potential future use.
Key Learning Points
- Unexplained infertility (10-15% of cases) is diagnosed when standard evaluation (ovulation assessment, tubal patency, semen analysis) is normal; subtle factors not detected by routine testing may be present
- For unexplained infertility, treatment typically progresses from ovulation induction + IUI (3-4 cycles) to IVF, though proceeding directly to IVF may be more cost-effective, especially in women over 35
- IVF success rates are approximately 40% per transfer for women under 35 using fresh embryos, declining with age; PGT-A for aneuploidy screening can improve implantation rates per transfer
- Elective single embryo transfer in good-prognosis patients achieves similar cumulative pregnancy rates while dramatically reducing multiple pregnancy risk