A novel method for assessing assisted female fertility: bioelectric impedance

Early detection of declining female fertility is important for effective prevention and treatment of infertility. Age, serum concentration of FSH in the early follicular phase (basal FSH), and the clomiphene citrate (CC) challenge test correlate only with large declines in fertility. We serendipitously discovered that by a novel mechanism bioelectric impedance (BEI) sensitively reflects early fertility decrements. BEI was measured between the right and left arms by the tetrapolar method before and during ovarian stimulation for in vitro fertilization (IVF). In a stepwise multiple logistic regression analysis of five factors (BEI on luteal day 4 prior to the IVF cycle [BEI-L4], age, basal FSH, body height, and body mass index), BEI-L4 alone was a significant predictor (P<0.05) of achievement of pregnancy by IVF in 148 women (74 pregnant and 74 nonpregnant). BEI showed a nadir on the day of administration of hCG in the pregnant but not the nonpregnant group. Serum concentrations of VEGF during ovarian stimulation were significantly higher in the pregnant group, but not those of 17beta-estradiol and progesterone. The CC challenge test revealed no significant difference between 11 pregnant and 15 nonpregnant women. The clinical usefulness of BEI was evaluated in 272 consecutive IVF cycles. Rate of pregnancy was significantly higher (P<0.01) in IVF cycles with BEI-L4 > or =600 Ohms than <600 Ohms (44% and 26% in 149 and 123 cycles, respectively). When BEI-L4 was > or =600 Ohms, pregnancy rates were constantly high irrespective of age and basal FSH. In prediction of nonpregnancy, sensitivity of BEI-L4 (0.52) was significantly (P<0.05) higher than those of age and basal FSH (0.39 and 0.046, respectively). BEI, which is easy, noninvasive, and inexpensive, predicts female fertility more sensitively than age and basal FSH, probably reflecting angiogenic capacity of reproductive organs.