title: Unexpected pregnancy despite extremely decreased estradiol levels during ovarian stimulation.
abstract: OBJECTIVE
  To report two patients with ongoing pregnancies despite a dramatically sharp decrease in E(2) levels after coasting.
  
  
  METHODS
  Case report.
  
  
  METHODS
  Reproductive endocrinology and assisted reproduction unit of university hospital.
  
  
  METHODS
  One 30-year-old and one 25-year-old woman, both with unexplained infertility, in whom E(2) levels increased up to 6345 and 14,275 pg/mL during ovarian hyperstimulation and decreased by 79.5% and 75.5%, respectively, after coasting.
  
  
  METHODS
  Two IVF treatments during which coasting was performed after high E(2) levels were observed. IVF cycles were carried out despite abrupt E(2) decrease.
  
  
  METHODS
  Development of ovarian hyperstimulation syndrome (OHSS) or fertilization, cleavage, implantation, and pregnancy rates.
  
  
  RESULTS
  Two embryos (one grade A and one grade B) were transferred into the 30-year-old patient and three embryos (all grade A) were transferred into the 25-year-old patient. Neither woman developed OHSS. Two pregnancies on going at gestational weeks 20 and 14, respectively.
  
  
  CONCLUSIONS
  Coasting is practiced to avoid severe complications of ovarian hyperstimulation during IVF cycles and is achieved by withholding gonadotropins. The aim of coasting is to lower E(2) levels to a safer range; however, there has been no consistency with respect to the time of coasting or the safety rates of E(2) decrease. We believe that high rates of E(2) decrease after coasting do not have deleterious effects on implantation.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology, Center for Assisted Reproduction and IVF, Ankara University School of Medicine, Ankara, Turkey.
authors.forename: Cem
authors.initials: C
authors.lastname: Atabekoglu
authors.forename: Murat
authors.initials: M
authors.lastname: Sonmezer
authors.forename: Sinan
authors.initials: S
authors.lastname: Ozkavukcu
authors.forename: Suheyla
authors.initials: S
authors.lastname: Isbacar
mesh_terms: D000328:Adult; D015536:Down-Regulation; D004334:Drug Administration Schedule; D010064:Embryo Implantation; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood*; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage; D005307:Fertilization in Vitro; D005865:Gestational Age; D006062:Gonadotropins / Q000008:administration & dosage; D006801:Humans; D007247:Infertility, Female / Q000378:metabolism / Q000628:therapy*; D054315:Oocyte Retrieval; D010062:Ovulation Induction; D011247:Pregnancy; D016896:Treatment Outcome
chemical_list: D005300:Fertility Agents, Female; D006062:Gonadotropins; D004958:Estradiol