For most women, fertility returns to pre-implant levels soon after removal, but in some cases is delayed for as long as 18 months.
Menstrual irregularities represent a common side effect, particularly during the first year of use.
Each of these preparations is safe and extremely effective. The 1995 National Survey of Family Growth found a 4 percent decline in the teenage birth rate between 1995 and 1996-dropping 17 percent from the peak rate in 1990, and 9 percent from the 1986 rate. The abortion rate among teenagers has also declined-31 percent since 1986. While EC should not be used as an ongoing form of contraception, EC can reduce the risk of pregnancy by as much as 75 or 80 percent, if administered within 72 hours following coitus. A recent randomized study found the levonorgestrel-only regimen to be more effective than the combination formulation and also better tolerated.