Timing of Sex
Intercourse timing and frequency relative to ovulation is possibly the most important factor affecting the chances of conception. It is also the element over which couples trying to conceive have the greatest degree of control.
Couples who are aware of their fertile time and have intercourse during this time become pregnant more quickly. Having sex during the fertile window also makes it easier for couples and their healthcare provider to decide whether not becoming pregnant is likely to be due to infertility rather than poor timing.
The ‘fertile window’ is determined by the lifespan of the sperm in the female reproductive tract and the life of the egg once it has been released at ovulation. Sperm live up to 3-5 days and the egg survives for 12-24 hours. Based on studies, the maximum fertile window has been determined to include the day of ovulation and the five days preceding ovulation. The most probable days for intercourse to result in pregnancy are 1 or 2 days before ovulation.
The currently available evidence suggests that methods that prospectively identify the window of fertility are likely to be more effective than calendar calculations or basal body temperatures, for optimal timing of intercourse. These include fertility charting of vaginal discharge and using commercially available fertility monitors. However, caution is advised when relying on urinary LH detection kits alone. The quality of cervical mucus falls rapidly as progesterone rises in response to the LH surge. Hence by the time the LH is detected by urinary ovulation kits, the cervical mucus quality may have already declined in most women.
The best time to attempt conception is when a woman’s cervical mucus is wet, slippery and of egg white consistency, usually over a 2-3 day period. The last day of this fertile type mucus is usually the day of ovulation and should be followed by a temperature rise. The temperature rise confirms that ovulation has taken place. As sperm can live for up to 3-5 days it is best to try and have intercourse in the 2-3 days preceding and on the day of egg release (ovulation).
Urine-based OPKs test the urine for an increase (surge) in luteinising hormone (LH). This happens one to two days before ovulation. A small amount of LH is always present in your blood and urine. But in the days before ovulation, the amount increases several times. The day before the LH surge until ovulation (12-24 hours after the start of the LH surge) is the most fertile time of your cycle. This is when you are most likely to conceive, so ensure that you do not wait until a positive LH test before having sex for conception.