title: Cumulative pregnancy rates after sequential treatment with modified natural cycle IVF followed by IVF with controlled ovarian stimulation.
abstract: BACKGROUND
  In modified natural cycle IVF (MNC-IVF), treatment is aimed at using the one follicle that spontaneously develops to dominance, using a GnRH-antagonist together with gonadotrophins in the late follicular phase only. The MNC-IVF is of interest because of its low-risk and patient-friendly profile. The effect of application of MNC-IVF preceding standard IVF with ovarian stimulation on overall results is unknown.
  
  
  METHODS
  This single-center cohort study provides follow-up of an earlier study in which nine cycles of MNC-IVF were offered to 268 patients. Ongoing pregnancy rates and live birth rates, as well as time-to-pregnancy after controlled ovarian stimulation-IVF (COS-IVF) following MNC-IVF, were evaluated.
  
  
  RESULTS
  Actual observed cumulative ongoing pregnancy rates and live birth rates after sequential treatment with MNC-IVF followed by COS-IVF were 51.5 (95% CI: 45.4-57.6) and 50.0% (95% CI: 43.9-56.1) per patient, of which 8.0 and 6.7% were twins. Median time to ongoing pregnancy was 28.8 weeks. Including treatment-independent pregnancies, cumulative ongoing pregnancy rate was 56.7% (95% CI: 50.7-62.8).
  
  
  CONCLUSIONS
  Sequential treatment with MNC-IVF followed by COS-IVF does not appear to compromise overall success rates, while twin pregnancy rate is low. Because of its patient-friendly and low-risk profile, it seems appropriate to perform MNC-IVF preceding COS-IVF.
authors.affiliation: Section of Reproductive Medicine, Department of Obstetrics and Gynaecology, University Medical Center Groningen, Groningen, The Netherlands. pelinck@hotmail.com
authors.forename: M J
authors.initials: MJ
authors.lastname: Pelinck
authors.forename: H M
authors.initials: HM
authors.lastname: Knol
authors.forename: N E A
authors.initials: NE
authors.lastname: Vogel
authors.forename: E G J M
authors.initials: EG
authors.lastname: Arts
authors.forename: A H M
authors.initials: AH
authors.lastname: Simons
authors.forename: M J
authors.initials: MJ
authors.lastname: Heineman
authors.forename: A
authors.initials: A
authors.lastname: Hoek
mesh_terms: D000328:Adult; D001724:Birth Weight; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods* / Q000706:statistics & numerical data; D043373:Follicle Stimulating Hormone, Human / Q000627:therapeutic use; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000627:therapeutic use; D006801:Humans; D007231:Infant, Newborn; D007247:Infertility, Female / Q000628:therapy; D010062:Ovulation Induction / Q000379:methods* / Q000706:statistics & numerical data; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D014427:Twins
chemical_list: D043373:Follicle Stimulating Hormone, Human; D007987:Gonadotropin-Releasing Hormone; C062876:cetrorelix