Home LH / Ovulation Testing
LH (Luteinizing Hormone) is the pituitary hormone that induces ovulation in the midcycle. This hormone is released from the brain into the circulation causing release of the egg 34-36 hours later. The hormone can also be identified in the urine and ovulation usually follows 12-24 hours later, with most patients ovulating by 48 hours after LH is first detected in the urine. Consequently, the most fertile days are the day of the surge and the next 2 days. For those patients undergoing intrauterine insemination (IUI), the optimal day for the procedure is the day after the surge is first detected.
Ovulation kits do not necessarily increase the chance of pregnancy in couples having regular intercourse, but they can be helpful in ovulatory women who have infrequent intercourse or who are having an IUI.
The LH surge starts in the morning for most women, and thus LH is detectable in the urine in the late afternoon. False positives and false negatives are commonly seen. False LH positives can be seen when high constant levels of LH occurs in the circulation (as seen in patients with polycystic ovaries) or a few days after taking ovulation induction drugs (Clomid, Femara). False negatives can occur with high fluid intake (dilution effect) or when the LH surge is too transient and occurs between testing times (twice-a-day testing can help minimize this, but is unnecessary for most patients).
Menses usually occur 14 days after the LH surge, therefore, LH testing should be started approximately 17 days before a menstrual period is expected, and can be stopped once a positive surge is detected.
Most LH kits today are very accurate, but the highest accuracy is found in those that are easy to use and interpret, and those with a high level of LH sensitivity. For a conclusive positive or negative result, digital kits appear to be the easiest to interpret.
According to a study from Johns Hopkins University published in Fertility and Sterility in May of this year, the highest performing products are: ClearPlan Easy Ovulation Test Pack, First Response, and Clear Blue Easy (they also have the One Month Ovulation Test).
Julian C. Escobar, M.D.
References: Brezina et al. F&S May 2011; Speroff et al. Clinical Gynecologic Endocrinology and Infertility, 8th Ed.
This entry was posted on Thursday, September 15th, 2011 at 5:50 pm and is filed under Diagnostics. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.
