Among the options provided, Intrauterine Devices (IUDs) are known to increase phagocytosis of sperms within the uterus and suppress sperm motility and fertilizing capacity.

IUDs are inserted by doctors or expert nurses in the uterus through vagina. These Intra Uterine Devices are presently available as the non-medicated IUDs (e.g., Lippes loop), copper releasing IUDs (CuT, Cu7, Multiload 375) and the hormone releasing IUDs (Progestasert, LNG-20)

IUDs, specifically copper-releasing IUDs, alter the uterine environment, creating conditions that are hostile to sperm survival. They promote the phagocytosis (engulfment and destruction) of sperm by the immune cells present within the uterus, reducing sperm motility and affecting their ability to fertilize an egg. Additionally, copper IUDs release copper ions, which further interfere with sperm function and viability.

Condoms act as a physical barrier method and do not influence sperm motility or function. Birth control pills (pills) and periodic abstinence work differently, primarily by preventing ovulation or altering hormone levels, respectively, rather than directly affecting sperm within the uterus.

Therefore, among the options listed, IUDs are the ones that increase phagocytosis of sperms within the uterus and suppress sperm motility and fertilizing capacity.