A 28-year-old woman from Delhi presents to the infertility clinic with a 2-year history of primary infertility. Her husband's semen analysis is normal. Menstrual cycles are regular (28 days), and pelvic ultrasound shows normal uterus and tubes. Serum FSH on day 3 is 6.2 mIU/mL, LH 5.8 mIU/mL, and prolactin 18 ng/mL. Thyroid function is normal. Progesterone on day 21 is 0.8 ng/mL, suggesting anovulation. She has never been treated for ovulation induction. Which agent should be offered first-line for ovulation induction in this patient?

Explanation

## First-Line Ovulation Induction in Anovulatory Infertility **Key Point:** Clomiphene citrate (CC) is the first-line agent for ovulation induction in anovulatory women with normal FSH levels and intact hypothalamic-pituitary-ovarian (HPO) axis. ### Rationale for Clomiphene Citrate 1. **Mechanism**: CC is a selective estrogen receptor modulator (SERM) that blocks negative feedback of estrogen on the hypothalamus and pituitary, leading to increased endogenous FSH and LH secretion. 2. **Efficacy**: Achieves ovulation in 70–80% of anovulatory women with normal baseline FSH. 3. **Cost-effectiveness**: Oral agent, inexpensive, easy to administer. 4. **Safety profile**: Well-tolerated with minimal side effects; no need for intensive monitoring. 5. **Success in this case**: Normal FSH (6.2 mIU/mL) and regular cycle length indicate intact HPO axis — ideal for CC response. ### Dosing Protocol - **Starting dose**: 50 mg daily for 5 days (days 3–7 of menstrual cycle). - **Monitoring**: Transvaginal ultrasound on day 10–12 to assess follicle growth. - **Trigger**: hCG 5000–10,000 IU when lead follicle ≥18 mm. - **Escalation**: If no response, increase to 100 mg daily in next cycle (up to 150 mg max). **High-Yield:** CC success rate is highest in women with PCOS and anovulation; lower in women with hypothalamic amenorrhea or severe FSH deficiency. ### Comparison with Alternatives | Agent | First-Line? | When Used | Advantage | Disadvantage | |-------|-----------|-----------|-----------|---------------| | **Clomiphene citrate** | Yes | Anovulation with normal FSH | Oral, cheap, safe | Adverse cervical mucus, thin endometrium | | **Letrozole** | Alternative | CC failure, PCOS, poor endometrium | Better endometrial thickness, cervical mucus | Off-label use; teratogenicity concerns (though reassuring data) | | **FSH (gonadotropin)** | No (2nd-line) | CC failure, hypogonadotropic hypogonadism | Direct stimulation | Injectable, expensive, requires monitoring, OHSS risk | | **GnRH agonist** | No | Hypogonadotropic hypogonadism (after priming) | Physiologic pulsatile release | Not for primary anovulation; requires pulsatile pump | **Clinical Pearl:** Clomiphene citrate should be avoided or used cautiously if baseline FSH >10 mIU/mL (suggests ovarian reserve depletion) or if there is evidence of hypothalamic amenorrhea (low FSH + low LH). **Warning:** Do not confuse clomiphene citrate (SERM, increases endogenous gonadotropins) with exogenous gonadotropins (FSH/LH injections). The latter is reserved for CC failure or hypogonadotropic states. [cite:Textbook of Obstetrics & Gynaecology, Hiralal Konar, Ch 12]