What is understood about how these two types function? Copper: As mentioned, IUDs seem to make it difficult for sperm to survive passing through the uterus to reach an egg.
اَلنَّوْعُ ٱلْأَوَّلُ يَحْتَوِي عَلَى ٱلنُّحَاسِ ،‏ وَصَارَ شَائِعًا فِي ٱلْوِلَايَاتِ ٱلْمُتَّحِدَةِ عَامَ ١٩٨٨ .‏