Association of endometrial thickness and pattern on pregnancy outcome in superovulation cycles

Abstract

OBJECTIVE: Limited data exist concerning the relationship between endometrial thickness and pregnancy outcome in superovulation cycles. This study sought to determine whether endometrial thickness and pattern as observed by transvaginal sonography was predictive of pregnancy outcome or related to first-trimester bleeding in those who conceived with superovulation.DESIGN: Retrospective analysis of endometrial thickness and pattern for patients who became pregnant while undergoing infertility treatment at the University of Michigan.MATERIALS AND METHODS: Between 1999-2007, 162 pregnancies were identified. Demographic data, infertility diagnosis, treatment type, bleeding history, endometrial thickness/texture on day of hCG, and pregnancy outcome were collected. Descriptive statistics were completed for all variables, including bivariate analysis by women with and without a live birth and by bleeding history. Regression models were used to test the associations between bleeding history, endometrial thickness, and having a live birth.RESULTS: The mean age was 32.4 ± 4.2 years. No difference was seen in BMI, gravidity or parity between those who had a live birth (n=130) and those who did not (n=29). The endometrial thickness in those who had a live birth was 9.9 ±2.4 vs 8.9 ± 2.2 mm in those who did not (p=0.05). Among those who bled, 51.3% had a live birth compared with 91.7% in those who did not (p<0.001). Women ≥38 years had a thicker lining compared to younger women: 11.3±2.8 vs 9.6±2.3; p=0.02. There was no difference in treatment type or endometrial pattern between patients in the live birth and no live birth categories. No difference was found in endometrial thickness or pattern between those who bled those who did not: 9.9±2.4 vs 9.4±2.4; p=0.25. The adjusted odds of having a live birth increased by 25% for every 1-mm increase in endometrial thickness (p=0.025). The adjusted odds of not having a live birth was 11.5 times greater among women with a history of bleeding compared to those without (p<0.0001).CONCLUSIONS: Women with a thicker endometrial lining had a higher likelihood of having a live birth. A thinner endometrial lining was not a risk factor for first trimester bleeding. Older women who conceived had a thicker endometrial lining compared to younger women. The difference in thickness seen between older versus younger women may suggest that, in addition to egg quality, endometrial thickness may play an important role in conception. Further studies evaluating endometrial thickness and age are needed. OBJECTIVE: Limited data exist concerning the relationship between endometrial thickness and pregnancy outcome in superovulation cycles. This study sought to determine whether endometrial thickness and pattern as observed by transvaginal sonography was predictive of pregnancy outcome or related to first-trimester bleeding in those who conceived with superovulation. DESIGN: Retrospective analysis of endometrial thickness and pattern for patients who became pregnant while undergoing infertility treatment at the University of Michigan. MATERIALS AND METHODS: Between 1999-2007, 162 pregnancies were identified. Demographic data, infertility diagnosis, treatment type, bleeding history, endometrial thickness/texture on day of hCG, and pregnancy outcome were collected. Descriptive statistics were completed for all variables, including bivariate analysis by women with and without a live birth and by bleeding history. Regression models were used to test the associations between bleeding history, endometrial thickness, and having a live birth. RESULTS: The mean age was 32.4 ± 4.2 years. No difference was seen in BMI, gravidity or parity between those who had a live birth (n=130) and those who did not (n=29). The endometrial thickness in those who had a live birth was 9.9 ±2.4 vs 8.9 ± 2.2 mm in those who did not (p=0.05). Among those who bled, 51.3% had a live birth compared with 91.7% in those who did not (p<0.001). Women ≥38 years had a thicker lining compared to younger women: 11.3±2.8 vs 9.6±2.3; p=0.02. There was no difference in treatment type or endometrial pattern between patients in the live birth and no live birth categories. No difference was found in endometrial thickness or pattern between those who bled those who did not: 9.9±2.4 vs 9.4±2.4; p=0.25. The adjusted odds of having a live birth increased by 25% for every 1-mm increase in endometrial thickness (p=0.025). The adjusted odds of not having a live birth was 11.5 times greater among women with a history of bleeding compared to those without (p<0.0001). CONCLUSIONS: Women with a thicker endometrial lining had a higher likelihood of having a live birth. A thinner endometrial lining was not a risk factor for first trimester bleeding. Older women who conceived had a thicker endometrial lining compared to younger women. The difference in thickness seen between older versus younger women may suggest that, in addition to egg quality, endometrial thickness may play an important role in conception. Further studies evaluating endometrial thickness and age are needed.