MMP1 and hydrops fetalis: Our primary IVW analysis revealed that higher genetically predicted levels of 3 inflammatory factors were associated with increased risk of HF: interferon gamma (OR = 1.080, 95% CI: 1.019–1.145, P = .010), matrix metalloproteinase-1 (OR = 1.081, 95% CI: 1.027–1.138, P = .003), and TNF-beta (OR = 1.064, 95% CI: 1.026–1.103, P < .001).