Rheses Negative-Anti D injection

Im rheses negative and my partner is not, now iv done a lot of research on this however im looking to know that if i dont have the anti D injection after my baby is born can i have it when i decide to have another baby, im not into having injections that are only for the IF factor or just in case! So if I have a positive baby, can i have the injection say next year if i decide to have another baby which i dont know if i will or not.? thanks any info will be much appriciated.