How many among the following, prevents implantation as well as ovulation?

Multiload 375, Mala-D, Norplant, Saheli

Solution:

Let's analyze the mechanism of action for each contraceptive method listed:

1. Multiload 375: This is a copper-releasing Intrauterine Device (IUD). IUDs primarily prevent implantation by making the uterus unsuitable for implantation and also affect sperm motility and fertilizing capacity. They generally do not prevent ovulation.

2. Mala-D: This is a combined oral contraceptive pill containing estrogen and progestin. Combined oral contraceptive pills primarily work by inhibiting ovulation, altering cervical mucus to prevent sperm entry, and making the uterus unsuitable for implantation. Thus, it prevents both ovulation and implantation.

3. Norplant: This is a progestin-only implant. Progestin-only methods primarily work by inhibiting ovulation, thickening cervical mucus, and thinning the uterine lining (making it unsuitable for implantation). Thus, it prevents both ovulation and implantation.

4. Saheli: This is a non-steroidal oral contraceptive (Centchroman). It works by preventing implantation and has minimal side effects. It does not inhibit ovulation.

Therefore, the contraceptives that prevent both implantation and ovulation are Mala-D and Norplant. There are two such methods.

Hence, the correct answer is Two.