A Randomized Controlled Trial of Intragastric Ballon Insertion versus Metformin for Methemoglobin-Induced Anovulation in Severe PCOS

International Journal of Obstetrics and Gynecology | Vol. 14, No. 8, August 2026 | pp. 435–446

DOI: 10.46882/2026/IJOG/000517

Original Research Article

Title: A Randomized Controlled Trial of Intragastric Ballon Insertion versus Metformin for Methemoglobin-Induced Anovulation in Severe PCOS

Names of Authors: Ibrahim K. Sanusi¹, Chioma J. Nwachukwu¹

Authors’ Affiliations:
¹ Department of Obstetrics and Gynecology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria

Abstract:
Polycystic Ovary Syndrome (PCOS) complicated by severe obesity presents complex metabolic blocks that impair normal ovulatory functions. This randomized open-label trial evaluated whether rapid weight loss induced via an endoscopic intragastric balloon (IGB) achieves superior ovulation restoration and insulin sensitivity compared to maximal metformin therapy in severely obese anovulatory women with PCOS. One hundred participants aged 18 to 35 years with a BMI ≥ 35 kg/m² and confirmed anovulation were randomized to receive either an fluid-filled IGB for 6 months (n = 50) or oral metformin titrated up to 2,000 mg daily (n = 50). The primary outcome was the percentage of women achieving spontaneous ovulation, confirmed via serial serum progesterone measurements (≥ 10 nmol/L) at month 6. The mean body weight loss was significantly higher in the IGB cohort compared to the metformin cohort (18.4% ± 3.5% vs. 4.2% ± 1.8%, p < 0.001). Spontaneous ovulatory cycles were restored in 76.0% of the IGB group compared to 38.0% of the metformin group (p < 0.001). Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) values improved substantially more in the balloon arm (mean reduction of 2.15 ± 0.45 vs. 0.85 ± 0.22, p < 0.001). Free testosterone concentrations also dropped further in the IGB cohort (p = 0.004). Endoscopic intragastric balloon placement drives superior weight reduction, leading to higher spontaneous ovulation restoration and improved insulin kinetics in severely obese anovulatory women with polycystic ovary syndrome.

Keywords: Polycystic Ovary Syndrome; Intragastric Balloon; Metformin; Weight Loss; Spontaneous Ovulation; Insulin Resistance.

Manuscript Timeline: Received: May 18, 2026; Revised: July 05, 2026; Accepted: July 24, 2026; Published: August 09, 2026.

Citation: Sanusi IK, Nwachukwu CJ. A Randomized Controlled Trial of Intragastric Ballon Insertion versus Metformin for Methemoglobin-Induced Anovulation in Severe PCOS. International Journal of Obstetrics and Gynecology. 2026; 14(8): 435–446.

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