Study of variables related to multiple pregnancy in cycles of ovarian stimulation

espanolIntroduccion: este trabajo analiza los ciclos de estimulacion ovarica seguidos de inseminacion intrauterina o coito programado que lograron embarazo. El objetivo es identificar las caracteristicas de la paciente o de la respuesta ovarica asociadas con el embarazo multiple. Material y metodos: es un estudio observacional retrospectivo descriptivo. Incluye 261 ciclos en los que se ha conseguido embarazo mediante inseminacion intrauterina o coito programado. La muestra se ha obtenido de 1.189 parejas infertiles tratadas de enero de 2009 a diciembre de 2014. Se evaluan caracteristicas potencialmente asociadas con el embarazo multiple dependientes de la paciente, del tratamiento aplicado y de la respuesta ovarica. Resultados: el 88,9% de los embarazos fueron unicos y el 11,1%, multiples (8,4% gemelares, 2,7% triples). En el grupo de embarazo multiple, la media de foliculos intermedios (14-16 mm), los foliculos con una media de ≥ 17 mm y el total de foliculos el dia de la gonadotropina corionica humana fueron mayores respecto al grupo de embarazo unico (p Conclusiones: este estudio confirma la asociacion entre embarazo multiple y mayor numero de foliculos. Desglosando los foliculos por su tamano y el embarazo multiple en gemelar y triple, los foliculos intermedios se asocian significativamente a embarazo gemelar, por lo que deben ser tenidos en cuenta en la decision de cancelacion para intentar disminuir el riesgo de embarazo multiple. EnglishIntroduction: This paper analyzes cycles of ovarian stimulation followed by intrauterine insemination or timed intercourse that resulted in pregnancy. Our objective was to identify characteristics of the patient or ovarian response that are associated with multiple pregnancy. Material and methods: We performed a descriptive retrospective observational study of 261 cycles where pregnancy was achieved by intrauterine insemination or timed intercourse. The sample was obtained from 1,189 infertile couples treated from January 2009 to December 2014. We evaluated features that were potentially associated with multiple pregnancy and dependent on the patient, treatment, and ovarian response. Results: Of all the pregnancies analyzed, 88.9% were singleton and 11.1% multiple (8.4% twins, 2.7% triplet). In the multiple pregnancy group, the average number of intermediate follicles (14-16 mm), follicles measuring ≥ 17 mm, and the total number of follicles on the day human chorionic gonadotropin was administered were higher than for the singleton pregnancy group (p Conclusions: This study confirms the association between multiple births and increased number of follicles. When follicles were classified by size and multiple pregnancy as twin and triplet, we found that intermediate follicles were significantly associated with twin pregnancy. Consequently, they must be taken into account when deciding to cancel a cycle in order to try to reduce the risk of multiple pregnancy.