Table I.

Summary of maternally controlled factors: expression in tubal ectopic pregnancy and potential causal effect in the development of tubal ectopic pregnancy.

Factor	Expression in tubal ectopic pregnancy	Potential effects
Inducible nitric oxide synthase (iNOS)	Reduced	Relaxed tubal smooth muscle contractility and/or ciliary beat resulting in reduced tubal motility
Interstitial cells of Cajal (ICC)	Reduced	Loss of pacemaker activity within the Fallopian tube resulting in reduced smooth muscle contractility
Endocannabinoid receptor (CB1)	Reduced	Aberrant tubal smooth muscle contractility
Prokineticin receptors (PROKRs)	Reduced	Aberrant tubal smooth muscle contractility
Activated macrophages	Increased	Up-regulation of prostaglandins resulting in aberrant tubal smooth muscle contractility
Interleukin-8 (IL-8)	Increased	Tubal tissue damage resulting from infection
Mucin 1 (MUC1)	Reduced	Allows implantation of abnormal embryos
Activins	Increased	Dysregulation of tissue remodelling allowing for tubal implantation
		Increased NOS production contributing to aberrant tubal motility