RELATIVE INFLUENCE OF SERUM FOLLICLE-STIMULATING-HORMONE, AGE AND OTHER FACTORS ON OVARIAN RESPONSE TO GONADOTROPIN STIMULATION

Objective To determine the relative value of the woman's age, basal fo llicle stimulating hormone (FSH), basal luteinising hormone (LH) and m enstrual cycle pattern (all defined prior to treatment) in predicting the ovarian response to gonadotrophin stimulation for in vitro fertili sation. Design Open, descriptive cohort study. Patients One hundred an d seventy-one consecutive ovulatory women undergoing their first cycle of in vitro fertilisation with ovarian stimulation after pituitary de sensitisation. Interventions Measurement of basal (early follicular ph ase) and down-regulated concentrations of serum FSH and LH, and calcul ation of age at treatment and of median length of menstrual cycles and range of variation prior to treatment.Main outcome measures Duration and amount of gonadotrophin stimulation to achieve follicular maturity , number of mature follicles, peak serum oestradiol concentration and number of mature oocytes, were compared between banded values of varia bles studied. Results Increasing basal FSH concentrations were signifi cantly associated with reducing oestradiol levels, numbers of mature f ollicles and oocyte yield even when the FSH levels were still within t he normal range though above average (6 to 8.9 i.u./l). There were sim ilar but weaker associations with FSH levels after down-regulation. Th ere were also significant differences between women over and under 40 years old in their oestradiol levels, numbers of follicles and of oocy tes. Analysis of variance showed significant independent association o f basal FSH with both oestradiol and numbers of oocytes, but not of ag e, menstrual pattern, or serum LH concentrations. Conclusion Serum FSH is more sensitive than the woman's age in determining her ovarian res ponsiveness to stimulation. LH concentrations and menstrual cycle patt erns are unhelpful.