Hello, In the event of your treatment for infertility through ICSI and blastocyst transfer, it is advisable not to indulge in sexual activity until the early trimester is over. This is to avoid pressure on the uterus. If you have never had a successful pregnancy that ran to term, uterine irritability as a causative factor has to be borne in mind. It is not necessary that you have the same outcome every time you get pregnant. Also, the time lapse between the pregnancies is so much that it is unlikely to influence. Success rate varies and can be up to 30-405 in advanced centers. Hope this helps.