title: The effect of exogenous hormones on the resistance of the early pregnant human cervix.
abstract: The force required to dilate the cervix to a diameter of 8 mm (cervical resistance index) has been measured in 355 patients undergoing suction termination in the first trimester of pregnancy. The cervical resistance index (CRI) was significantly lower in multigravid patients compared with primigravid patients. Prior treatment with prostaglandin E2 pessaries produced a consistent reduction in CRI in multigravidae but not in primigravidae. The effect of the prostaglandin was more pronounced on the compliance of the cervical tissue than on the diameter of the cervical canal. Treatment with pessaries of oestradiol, progesterone and medroxy-progesterone acetate produced no changes in the CRI.
mesh_terms: D002584:Cervix Uteri / Q000187:drug effects / Q000502:physiology*; D004107:Dilatation and Curettage; D015232:Dinoprostone; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006801:Humans; D008525:Medroxyprogesterone / Q000031:analogs & derivatives / Q000494:pharmacology; D017258:Medroxyprogesterone Acetate; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D010298:Parity; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011374:Progesterone / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology*
chemical_list: D011458:Prostaglandins E; D011374:Progesterone; D004958:Estradiol; D017258:Medroxyprogesterone Acetate; D008525:Medroxyprogesterone; D015232:Dinoprostone