Which of the following is not a natural method of contraception?

The correct answer is Option (4) → Intra uterine devices

Option (1) Periodic abstinence — A natural method.

Option (2) Lactational amenorrhoea — A natural method.

Option (3) Coitus interruptus — A natural method.

Option (4) Intra uterine devices — Not a natural method. An IUD is a device inserted by a doctor or nurse into the uterus. Natural methods use no medicine or device.

Note: A similar question was also asked in CUET (UG) 2023 on 07-06-2023 (Slot 2).

NCERT Extract:
Population Stabilisation and Birth Control – “… Natural methods work on the principle of avoiding chances of ovum and sperms meeting. Periodic abstinence is one such method in which the couples avoid or abstain from coitus from day 10 to 17 of the menstrual cycle when ovulation could be expected. As chances of fertilisation are very high during this period, it is called the fertile period.”
Population Stabilisation and Birth Control – “… Another effective and popular method is the use of Intra Uterine Devices (IUDs).”
Population Stabilisation and Birth Control – “… Lactational amenorrhea (absence of menstruation) method is based on the fact that ovulation and therefore the cycle do not occur during the period of intense lactation following parturition. Therefore, as long as the mother breast-feeds the child fully, chances of conception are almost nil.”