The normal range of progesterone in 9 weeks of pregnancy is 63.6~95.4nmol/L. Progesterone 19.3nmol/L belongs to the lower progesterone, which may be caused by luteal insufficiency, thyroid and adrenal function abnormality, etc., and it can be treated by medication as prescribed by the doctor. 1. Luteal insufficiency: refers to poor development of the corpus luteum after ovulation, insufficient secretion of progesterone or premature degeneration of the corpus luteum, resulting in reduced secretion and responsiveness of the endometrium. Luteal supplementation therapy can be carried out, this method is to supplement progesterone to improve the luteal function, commonly used drugs such as progesterone. 2. Abnormal thyroid and adrenal function: this can lead to hormone metabolism disorders in the body, affecting the ovarian function, causing ovulation abnormalities, and progesterone content will be reduced accordingly. Hormonal drugs can be used to maintain hormonal balance in the body, commonly used hydrocortisone and so on. Pregnant 9 weeks progesterone 19.3nmol / L there are other reasons, it is recommended to go to the hospital in a timely manner to avoid low progesterone lead to fetal arrest, the use of medication need to be used under the guidance of a doctor, do not blindly use their own medication.