Endometrial receptivity and conception outcome among women with light menstrual bleeding of unidentified etiology

ObjectiveTo investigate endometrial receptivity (ER), conception outcome, and other factors among women with light menstrual bleeding of unidentified etiology. MethodsA prospective study was undertaken at a center in China. Between January 1, 2011, and December 31, 2014, women meeting the inclusion criteria (aged 20-35years, without any history of pregnancy, desire to conceive, follicle-stimulating hormone <10IU on second or third day of cycle, and regular menstrual periods) were enrolled. Participants with a menstrual blood volume of 5-20mL formed the study group; others were in the control group. ER measures were obtained by transvaginal Doppler ultrasonography. Serum estradiol and progesterone levels were measured and items of prethrombotic state were screened in mid-luteal phase. Participants were followed up for 1year to establish conception outcome. ResultsThe ER (Salle) score was significantly lower in the study group (n=110) than in the control group (n=330; 9.413.02 vs 15.672.63, P<0.001). The natural rate of conception within 1year was lower (60.0% [63/105] vs 72.1% [230/319], P=0.020), and the spontaneous abortion rate in early pregnancy was higher (34.4% [21/61] vs 18.1% [41/227], P=0.006) in the study group than in the control group. ConclusionWomen with light menstrual bleeding of unidentified etiology had an increased prevalence of low ER and poor conception outcome. Women with light menstrual bleeding of unidentified etiology had an increased prevalence of low endometrial receptivity and poor conceptionoutcomes.