As someone who suffers from an autoimmune disease, anti-inflammatories (or more specifically NSAIDs Non-Steroidal Anti-Inflammatory Drugs) are often my best friend. I’ve been on and off them for probably close on 15 years and have often relied on them to help me make it through the day. So when my husband and I were trying to conceive I kept on popping them without a thought, while weaning myself off of all the hectic autoimmune disease drugs such as methotrexate that I was advised to get off of before conception (you need to be off of methotrexate for at least 4 months before you conceive). Then because things were taking a little longer than I would of hoped, I started to investigate the effect of the NSAID I was still taking on fertility. I was stunned by what I found, even more so because not one of my doctors had mentioned it.
NSAIDs can interrupt, delay or stop ovulation due to the action of the NSAID on the cox-2 enzyme and its role in the development of prostaglandins (a fatty molecule involved in the regulation of inflammation) . If you think about ovulation, it is essentially an inflammatory process with the follicle on the ovary swelling and eventually bursting to release the egg. If you don’t allow for this inflammation then ovulation cannot occur.
In fact some NSAIDs are so good at stopping ovulation that they have been investigated for their use as contraceptives or as morning-after pills [2, 3]! Unfortunately it is not just prescription anti-inflammatories (such as Arcoxia and Celebrex, Mypaid and Myprodol) that can cause this, anti-inflammatories available over the counter are responsible as well (such as Voltaren, Cataflam, Nurofen , Advil) .
So if you are trying to conceive, think carefully about popping a pill for a headache or backache.
 M. Gaytán, C. Morales, C. Bellido, J.E. Sánchez-Criado and F. Gaytán, “Non-steroidal anti-inflammatory drugs (NSAIDs) and ovulation: lessons from morphology”, Histol Histopathol Vol. 21, pp. 541-556, 2006 http://europepmc.org/abstract/med/16493584
 Edelman AB, Jensen JT, Doom C, Hennebold JD, “Impact of the prostaglandin-synthase 2 inhibitor celecoxib on ovulation and luteal events in women. “, Contraception, 87(3), pp. 352-357, 2013 https://www.ncbi.nlm.nih.gov/pubmed/22902348
 McCann NC, Lynch TJ, Kim SO and Duffy DM, “The COX-2 inhibitor meloxicam prevents pregnancy when administered as an emergency contraceptive to nonhuman primates”. Contraception. 88, 2013 https://www.ncbi.nlm.nih.gov/pubmed/24120248
 Salman S, Sherif B & Al-Zohyri A, “Effects of some non-steroidal anti-inflammatory drugs on ovulation in women with mild musculoskeletal pain.” Annual European Congress of Rheumatology, 2015 http://www.pharmaceutical-journal.com/news-and-analysis/nsaid-use-may-prevent-fertile-women-from-ovulating/20068779.article