PROBLEM TO BE SOLVED: To provide methods of decreasing the risk of premature birth and miscarriage in human females, and to provide methods even applied to a pregnant female if she suffers from such a symptom as, but not limited to, early contractions, cramps in her lower abdomen, low dull pain in her back, pressure in her pelvic area, stomach cramps, vaginal discharge, vaginal bleeding and vaginal watery fluid leakage.SOLUTION: A method of reducing rate of cervical dilation comprises administering a pharmaceutical formulation comprising pharmaceutically active relaxin (a disulfide bridged polypeptide hormone of approximately 6000 daltons) to a pregnant human female to reduce the rate of cervical dilation, wherein the relaxin is human H2 relaxin and is administered to a pregnant female in an amount in a range of about 0.1 to 500 &mu；g/kg of subject body weight. The relaxin is administered to the female so as to maintain a serum concentration of the relaxin from about 0.5 to 50 ng/ml.【課題】ヒト女性において早産及び流産の危険性を低減する方法、並びに早期収縮、下腹部の痙攣、腰の鈍痛、骨盤領域の圧迫、胃痙攣、膣分泌物、膣出血、及び膣水状液漏れ等の(但しこれらに限定されない)症状に直面している場合の妊娠女性にも適用できる方法の提供。【解決手段】医薬的に活性なリラキシン（約6000ダルトンのジスルフィド架橋ポリペプチドホルモン）を含む医薬製剤を妊娠しているヒト女性に投与して子宮頚管の拡張度を低減する工程を含む方法。前記リラキシンがヒトＨ２リラキシンであり、０．１～５００μｇ／ｋｇ（被験体の体重）の範囲で妊娠している女性に投与し、前記女性のリラキシンの血清中濃度を０．５～５０ｎｇ／ｍｌを維持する様にリラキシンを投与する方法。【選択図】なし
