Tubal-factor infertility and tubal surgery — structured SAQ (15 marks)

(a) Effect of hydrosalpinx on IVF outcomes and mechanisms (3 marks)

One mark for the outcome, one for the magnitude, one for the mechanisms. [2][3]

• Outcome: a hydrosalpinx lowers IVF implantation and pregnancy rates and raises miscarriage.[2]
• Magnitude: the Zeyneloglu meta-analysis found clinical pregnancy and implantation rates were roughly halved and miscarriage was more than doubled in women with a hydrosalpinx.[2]
• Mechanisms: embryotoxic hydrosalpingeal fluid leaking into the uterine cavity, mechanical washout of embryos, and altered endometrial receptivity (cytokine disruption).[3]

(b) Surgical options before IVF, with evidence and recommendation (5 marks)

One mark per option with its evidence, one for the recommendation, one for the rationale. [1]

• Laparoscopic salpingectomy — first line. The Melo Cochrane found salpingectomy before IVF probably increases clinical pregnancy versus no surgery (risk ratio 2.02, 95% CI 1.44 to 2.82, moderate-quality evidence). The Strandell randomised trial showed salpingectomy improved cumulative IVF outcome.[1][6]
• Proximal tubal occlusion — alternative. The Cochrane found proximal occlusion may increase clinical pregnancy versus no surgery (RR 3.21, 95% CI 1.72 to 5.99, low quality), used when salpingectomy is technically difficult or ovarian-reserve concerns favour a more conservative approach.[1]
• Transvaginal aspiration — inferior and temporary. RR 1.67 (95% CI 1.10 to 2.55, very low quality); fluid reaccumulates, so it is reserved for when surgery is not possible.[1]
• Recommendation here: laparoscopic left salpingectomy, preserving the ovarian blood supply. The Capmas systematic review confirms that managing a hydrosalpinx (by any method) improves IVF pregnancy, with no significant difference in ovarian response except a small drop in AMH after salpingectomy.[3]

(c) Why NOT to offer reconstructive tubal surgery here (3 marks)

One mark for the principle, one for the female-factor context, one for the ectopic risk. [1]

• She has only one remaining tube, already damaged (distal occlusion with a hydrosalpinx); reconstructive surgery on a single severely diseased tube has poor prospects and risks consuming her ovarian reserve.[1]
• Reconstructive surgery is reserved for young women with mild disease and good mucosa; her disease is severe (hydrosalpinx), and her stated goal is IVF.[1]
• A patent but mucosa-damaged tube carries ongoing ectopic risk without restoring fertility — patency is not function.[2]

(d) Oil-based versus water-based HSG evidence and applicability (2 marks)

One mark for the evidence, one for applicability. [4][5]

• Evidence: the Dreyer H2Oil trial (NEJM 2017) found oil-based contrast gave higher ongoing pregnancy (39.7% vs 29.1%) and live birth (38.8% vs 28.1%) than water-based within 6 months; the Wang network meta-analysis confirmed oil flushing raised clinical pregnancy versus water-based (OR 1.67) and no flushing (OR 2.28).[4][5]
• Applicability: the benefit applies to women with unexplained or mild disease undergoing HSG. Her problem is a confirmed hydrosalpinx destined for IVF, so oil flushing does not substitute for salpingectomy — it would not address the embryotoxic fluid.[2]

(e) Effect of declining ovarian reserve on further surgery (2 marks)

One mark for the principle, one for the AMH caveat. [3][1]

• With an AMH of 6 pmol/L she has diminished ovarian reserve; the priority is to protect remaining oocytes and move to IVF, not to undertake further tubal surgery that could compromise ovarian blood supply.[3]
• The Capmas review noted no major ovarian-response difference after salpingectomy except a small AMH decline; in a low-reserve woman, avoid repeat ovarian-compromising surgery and, if a hydrosalpinx recurs, favour proximal occlusion over salpingectomy where feasible, or proceed straight to IVF.[3]