Which of the following methods of birth control is considered the most effective?

Which of the following statements is true regarding $IUDs$ used by females?

Find out the correct aspects of lactational amenorrhoea.
$I$. Ovulation does not occur during the lactational period.
$II$. Chances of the failure of contraception are almost nil up to six months following parturition.
$III$. Side effects are almost nil.
$IV$. It is a natural method of contraception.
$V$. It increases phagocytosis of sperms.

Give scientific reasons: Pregnancy can be stopped or prevented without artificial methods of family planning.

$A$ method of birth control is:

Select the incorrect statement about contraceptives.