Progesterone value of 50ng/ml at five weeks of pregnancy may or may not be twins, further observation or examination is needed. Progesterone will gradually rise in early pregnancy, generally speaking, at five weeks of pregnancy, the value of progesterone should be more than 15ng/ml, at five weeks of pregnancy, progesterone is still mainly secreted by the ovarian corpus luteum, at this time, the level of progesterone is mainly by the ovary’s secretion function is determined, and the number of fetuses does not have a direct link. At this time, the progesterone 50ng / L may be twins, or only a single fetus. At the same time, it is necessary to pay attention to whether the calculation of gestational weeks is accurate, if the calculation of gestational weeks is less than the actual number of weeks, it is also possible to show high progesterone value. In conclusion, it is advisable to consult a doctor to determine the number of fetuses by ultrasound. It is advisable to consult a medical professional if necessary.