Hello and welcome to Healthcare Magic. Thanks for your query.
injections, when taken regularly, have the highest efficacy for birth control. The perfect use failure rate is estimated to be less than 0.3%. However, only a maximum delay of 2 weeks is acceptable and the medication loses its efficacy beyond 2 weeks of delay.
So, it is likely that you have not been covered by the contraceptive in the 2 weeks prior to your second shot. But you also have to remember that even in pregnancy
, there are noticable changes in the tummy before two weeks. So, your tummy becoming large is not a reliable indicator of your pregnancy. I would advise you to have a urine pregnancy test done in case you have missed a period and are suspecting the possibility of pregnancy.
Wish you all the best.
Dr. Jonas Sundarakumar