Age, independent from ovarian reserve status, is the main prognostic factor in natural cycle in vitro fertilization.
OBJECTIVE
To analyze natural cycle IVF (NC-IVF) results according to patient age, ovarian reserve status following the Bologna criteria, cause of infertility, and modification of the cycle with the use of GnRH antagonist.


METHODS
Retrospective cohort study.


METHODS
Tertiary-care university hospital.


METHODS
Nine hundred forty-seven natural cycles carried out in 320 patients.


METHODS
Analysis of 947 NC-IVF outcomes performed in one single center between January 2010 and December 2014.


METHODS
Pregnancy rates per cycle started, per ET, and per patient, as well as ongoing pregnancy rate at a minimum of 12 weeks of gestation.


RESULTS
Among the three age groups analyzed (≤35 years, 36-39 years, and ≥40 years), pregnancy rates per cycle were significantly lower in the older group of patients (11.4% vs. 11.6% vs. 5.9%). In addition, miscarriage rate (7.7% vs. 34.4% vs. 50%) and ongoing pregnancy rate (10.6% vs. 7.6%vs. 3.0%) were negatively affected by patient age. However, no differences were observed according to patient ovarian reserve status, cause of infertility, or modification of the cycle with GnRH antagonist. The multivariate logistic regression confirmed that patient age was the only variable that could predict pregnancy in NC-IVF cycles (odds ratio, 0.93; 95% confidence interval, 0.88-0.98).


CONCLUSIONS
NC-IVF is a feasible and "patient-friendly" option to be offered to young patients, independent of their ovarian reserve status.
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain. Electronic address: igonzalf@clinic.ub.es.
Iñaki
I
González-Foruria
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Juana
J
Peñarrubia
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Aina
A
Borràs
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Dolors
D
Manau
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Gemma
G
Casals
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Sara
S
Peralta
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Montserrat
M
Creus
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Janisse
J
Ferreri
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Ester
E
Vidal
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Francisco
F
Carmona
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Juan
J
Balasch
Institut Clinic of Gynecology, Obstetrics and Neonatology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Medicine, University of Barcelona, Barcelona, Spain.
Francisco
F
Fàbregues
D000022:Abortion, Spontaneous / Q000209:etiology; D000328:Adult; D016009:Chi-Square Distribution; D005260:Female; D005298:Fertility; D005300:Fertility Agents, Female / Q000008:administration & dosage; D005307:Fertilization in Vitro / Q000009:adverse effects; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors; D006727:Hormone Antagonists / Q000008:administration & dosage; D006785:Hospitals, University; D006801:Humans; D007247:Infertility, Female / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D016015:Logistic Models; D008423:Maternal Age; D015999:Multivariate Analysis; D016017:Odds Ratio; D065851:Ovarian Reserve / Q000187:drug effects; D010053:Ovary / Q000187:drug effects / Q000503:physiopathology*; D018579:Patient Selection; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D012307:Risk Factors; D013030:Spain; D062606:Tertiary Care Centers; D016896:Treatment Outcome
D005300:Fertility Agents, Female; D006727:Hormone Antagonists; D007987:Gonadotropin-Releasing Hormone
Bologna criteria; GnRH antagonist; Natural cycle IVF; endometriosis; poor ovarian response