Objective To explore the correlation between the last menstruation

last ovulation phase of the moon and the incidence of early miscarriage. Methods A two-way cohort study was designed. Infertility patients who have successfully become pregnant at the outpatient clinic of Longhua Hospital were selected. According to the moon phase of the last menstrual

they were divided into a menstrual new moon group with 491 cases

a menstrual first quarter moon group with 454 cases

a menstrual full moon group with 484 cases and a menstrual last quarter moon group with 403 cases. According to the moon phase of the last ovulation time

they were divided into an ovulation new moon group with 478 cases

an ovulation first quarter moon group with 432 cases

an ovulation full moon group with 489 cases and an ovulation last quarter moon group with 453 cases. From the day when the pregnancy was confirmed

the patients were treated with integrated traditional Chinese and western medicine to protect the fetus until 12 weeks or more than 2 weeks after the previous miscarriage. The pregnancy distribution of patients in different grouping methods and the incidence of early miscarriage were compared. Results Grouped according to the time of last menstruation and time of last ovulation

the number of pregnancies in the new moon group and the full moon group were more than those in the first quarter and last quarter moon group. The incidence of early miscarriage was 16.3% in the menstrual new moon group

17.6% in the first quarter moon group and the menstrual full moon group

and 20.1% in the menstrual last quarter moon group; the early abortion rate was 15.1% in the ovulation new moon group

17.1% in the ovulation group first quarter moon

19.2% in the ovulation full moon group

and 19.4% in the ovulation last quarter moon group. There was no significant difference in the early miscarriage rate among the groups（P>0.05）. Conclusion The incidence of early miscarriage in infertile women had no correlation with the moon phase of the last menclature and the last ovulation.