Well this blew my mind.
Results from a recent study suggest that taking an anti-inflammatory such as ibuprofen could prevent or delay ovulation. Used by over 30 million people worldwide and available over the counter they are usually used for common ailments such as back ache, period pain or musculature pain.
“In the study 39 women of childbearing age who suffer from back pain took part in the study, and received diclofenac (100mg once daily), naproxen (500mg twice daily) and etoricoxib (90mg once daily) or placebo. Treatment was given for 10 days from day 10 of the onset of the menstrual cycle; hormonal analysis (progesterone level) and follicle diameter were conducted via blood sample and ultra sonsography respectively. At the end of the NSAID treatment period, the dominant follicle remained unruptured in 75 percent, 25 percent and 33 percent of patients receiving diclofenac, naproxen and etoricoxib respectively. Rupturing of the dominant follicle, and subsequent release of an oocyte (unfertilised egg), is essential for ovulation to occur.”
You can read about the study here.
So if you are trying for children, it might be an idea to steer off them or use paracetamol or another pain killer or use them at the very start of your cycle and at no other time.
On the other hand it may open the door for emergency contraceptives. More research is needed!