Predicting Ovulation and Monitoring IUI Cycles
The timing of the intrauterine insemination is important to maximizing the chance of pregnancy. While sperm can last for several days in the female reproductive tract, the egg can only be fertilized within a 24 hour period (approximate). The sperm must travel through the fallopian tube to reach an egg and IUI increases the number of sperm making fertilization more likely.
Ovulation predictor kits (OPK) allow women to test their urine for LH at home to determine the time of the “surge” with 90-95% accuracy. During the menstrual cycle luteinizing hormone (LH) rises (“surge”) 36-40 hours prior to release of the egg.
Follow the kits instructions and begin testing on day 10 of your cycle. Cycle day one is considered the first day of the menstrual cycle and the test should be done before 5:00 PM. Testing is done once daily at approximately 11:30 AM or twice daily, early morning and evening. Ovulation will most likely occur between days twelve and twenty..
When your test is positive call the office as soon as possible to schedule the IUI. If you surge in the evening, call us the next morning when the office opens. If you have an LH surge on a day we are closed, call our answering service at (866) 774-1266 and the physician on call will be contacted. Call us for further instructions if you don't surge by day 18.
If the test is positive in the morning or at noon, we usually perform IUI the next day. If it is negative in the morning and positive in the evening, we usually perform IUI the next afternoon or the following morning (1.5 days later).
The menses will occur 13-15 days after the positive LH surge. If the menses doesn’t start, the patient is either pregnant or ovulation did not occur (false positive OPK test). If the OPK testing seems inaccurate, we do a blood test for LH (should be high >30) in the next IUI cycle. We often check a blood progesterone level 7 days after the IUI to confirm that ovulation with good luteal progesterone production occurred.
Women with PCOS often have elevated LH levels which can cause the OPK test to be falsely positive for several days.
Additional Cycle Monitoring
- Ultrasound to confirm the number and maturity of the follicles and the thickness of the lining of the uterus (endometrium). Thickness greater the 6 mm is desired. Clomid can cause a thin lining if taken for more than 3-4 months.
- Blood estradiol levels to confirm healthy mature follicles.
- Transvaginal ultrasounds, estradiol, LH and progesterone measurements are done when FSH is used. This helps avoid multiple births, FSH side effects and can determine the best time to give the hCG injection (hormone to induce final maturation).