Ovarian response is a better predictor of clinical pregnancy rate following embryo transfer than is thin endometrium or presence of an endometrioma.
OBJECTIVE
To examine whether endometrial thickness and the presence of endometrioma are independent predictors of clinical pregnancy rate or simply associated with poor ovarian response (POR).


METHODS
This was a retrospective cohort study assessing the first cycle of all women undergoing in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in a university hospital in Brazil between January 2011 and December 2012. Only the first cycle of each woman within the study period was considered. Women over 40 years of age and those who used clomiphene citrate during controlled ovarian stimulation (COS) or did not undergo embryo transfer were excluded from analysis. POR was defined as ≤ three oocytes retrieved and a thin endometrium was defined as endometrial thickness ≤ 7.0 mm on the day of human chorionic gonadotropin (hCG) administration. We performed a multiple regression analysis to identify which of the following parameters were independent predictors of clinical pregnancy: age, number of oocytes retrieved, endometrial thickness or the presence of endometrioma.


RESULTS
Within the study period, 787 women began COS, but 270 were excluded from analysis. Among the 517 women analyzed, those who achieved pregnancy were younger and yielded more oocytes. The proportion of POR was higher in women with a thin endometrium (17/57 (29.8%) vs 80/460 (17.4%); P = 0.03) and in women with endometrioma (15/39 (38.5%) vs 82/478 (17.2%); P = 0.002). The results of regression analysis showed that only age and the number of oocytes retrieved were independent predictors of pregnancy. Additionally, we observed higher clinical pregnancy rates in women with a thin endometrium from whom ≥ seven oocytes were retrieved (11/25 (44.0%)) compared to women with normal endometrial thickness (99/241 (41.1%)). Considering only women from whom ≥ four oocytes were retrieved, we observed reasonable pregnancy rates in those with a thin endometrium (14/40 (35.0%)) and in those with endometrioma (9/24 (37.5%)).


CONCLUSIONS
Both a thin endometrium and the presence of endometrioma are associated with POR but are not important independent predictors of clinical pregnancy. Good pregnancy rates can be observed when these conditions are present in women with a good ovarian response.
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo (DGO-FMRP-USP), Ribeirao Preto, Brazil.
M A
MA
Coelho Neto
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo (DGO-FMRP-USP), Ribeirao Preto, Brazil.
W P
http://orcid.org/0000-0002-7593-5607
WP
Martins
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo (DGO-FMRP-USP), Ribeirao Preto, Brazil.
M L S
ML
Lima
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo (DGO-FMRP-USP), Ribeirao Preto, Brazil.
M A P
MA
Barbosa
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo (DGO-FMRP-USP), Ribeirao Preto, Brazil.
C O
CO
Nastri
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo (DGO-FMRP-USP), Ribeirao Preto, Brazil.
R A
RA
Ferriani
Department of Obstetrics and Gynecology, Ribeirao Preto Medical School, University of Sao Paulo (DGO-FMRP-USP), Ribeirao Preto, Brazil.
P A
PA
Navarro
D000328:Adult; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D015331:Cohort Studies; D004624:Embryo Transfer / Q000009:adverse effects / Q000379:methods*; D004715:Endometriosis / Q000175:diagnosis / Q000503:physiopathology*; D004717:Endometrium / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology; D005260:Female; D006801:Humans; D010053:Ovary / Q000187:drug effects / Q000502:physiology*; D010062:Ovulation Induction / Q000379:methods; D011237:Predictive Value of Tests; D011247:Pregnancy; D018873:Pregnancy Rate; D012044:Regression Analysis; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000009:adverse effects / Q000379:methods; D016896:Treatment Outcome; D014463:Ultrasonography
D006063:Chorionic Gonadotropin
ICSI; IVF; endometrial receptivity; endometrial thickness; endometriosis; poor ovarian response; ultrasound