Ovulation usually occurs about 12-16 days before the next menstrual period, and the most fertile days are typically around the middle of the cycle. Since your wife’s last periods were on 1 February and 5 March, assuming her cycles are roughly 28-30 days, her likely ovulation would be around 14-18 February and 19-23 March, and the best time for intercourse to increase the chances of pregnancy is during these days and a few days before, having sex every 1-2 days. Keep in mind that cycle lengths can vary, so tracking menstrual cycles, observing ovulation signs like cervical mucus changes, or using ovulation kits can help identify the most fertile days more accurately. Consulting a doctor is also helpful if you plan to conceive or have been trying for some time.