How Do Birth Control Pills Work? - Types, Effectiveness & Medications to Avoid

Birth control pills, also known as contraceptives, help to prevent pregnancy by acting as an efficient birth control option. This contraception contains steroid hormones, namely, progesterone and oestrogen, in specific combinations that work towards changing the hormone levels in a woman’s body to deter chances of pregnancy. 

Let us take a close look at how birth control pills work and how to increase their effectiveness.

Commonly referred to as “the pill”, oral contraceptives come in the form of pills and are of several types and brands based on hormonal combinations. The pills are taken by mouth once daily, but the dosage and effectiveness vary among individuals.

The underlying section discusses how birth control pills work to prevent unwanted pregnancy in women.

Birth control pills work to prevent pregnancy by averting ovulation or the process of release of an egg cell from ovaries. Additionally, contraceptives prevent pregnancy by causing the following changes to a female body:

Step 1: Thickens the mucus layer at uterine opening making it harder for the sperm cells to penetrate the mucosal layer and from entering the uterus.

Step 2: Thins uterine tissue lining in womb to reduce chances of implantation of the fertilised egg and from further development into a foetus. 

By averting these essential reproductive processes every month, a birth control pill assures 99% effectiveness in preventing pregnancy if taken in the correct dosage as per individual requirements.

Oral pills come in mainly 3 types and are marketed by different brands based on different steroid hormone combinations. These are described below:

1. Phasic Oral Pills (21-day)

Phasic pills have different hormone concentrations and come in one pack. Each pack has 2 or 3 sections of pills of varying combinations. A single pill needs to be taken every day for 21 days. This is to be followed by a period of discontinuation for the next 7 days in a month.

It is mandatory to take the pills at the correct dosage and at the right time every day. For example - Logynon is a phasic pill.

2. Monophasic Oral Pills (21-day)

Monophasic birth control pills are the most commonly used oral pills Each such pill contains hormones in similar concentrations and must be taken every day for a continuous period of 21 days to show the highest effectiveness. This is to be followed by a period of discontinuity for 7 more days to complete a monthly cycle of pill intake. 

For example – A few monophasic oral pills are Marvelon, Yasmin and Microgynon.

3. Every Day Pills or ED Pills

A pack of Every Day (ED) pills contains 7 inactive pills and 21 active ones. The 7 inactive oral pills are often called dummy pills. These two variants of pills in a pack look different and have different compositions. 

ED pills need to be consumed orally every day for a continuous period of 28 days of a month. Therefore, the intake of ED pills needs to follow the correct order, and a user needs to follow the instruction manual carefully. If the pills are not consumed at the right time every day or are missed at times, their effectiveness decreases.

For example – A common ED pill is Microgynon.

Also, one must consult with a medical practitioner before consumption of a type of oral pill. They will provide proper guidance to a user on how pregnancy pills work and the correct dosage. When oral pills are consumed with certain medications, their effectiveness may decrease. 

A doctor will consider all these to guide a user with a contraceptive which best suits an individual’s needs. Before starting an oral pill, one must know how to take contraceptive pills.

Birth control pills show maximum effectiveness when taken at the proper time and in the correct dosage. Below are the regimes a user should follow for consuming 21-day pills (phasic and monophasic) and ED pills. However, every user has a unique health metric, and one should always consult a medical practitioner before starting a regime.

1. Standard Regime

The standard regime to follow for 21-day pills and ED pills are described below:

• Phasic and Monophasic Pills (21-day Pills)

One needs to follow the following steps to consume 21-day pills as per the standard regime.

Step 1: One must take the 1st oral pill starting from the correct day of the week, as marked in the pill packet or take the 1st oral pill of first colour. 

Step 2: The user must continue taking the pill at the same time every day for the ongoing 21 days

Step 3: One needs to stop pill consumption for the next 7 days, which is the time when one may experience bleeding.

Step 4: Following this, the user must start with the next pack of oral pills on the 8th day, regardless of whether the bleeding continues. 

[NOTE: This day of the week should be the same day on which the 1st pill was started.]

• Every Day (ED) Pills

One needs to follow the following steps to consume ED pills as per the standard regime.

Step 1: A user must take the 1st pill from the packet’s section marked as ‘start’. This should not be a dummy pill but an active one.

Step 2: The user must now continue to consume 1 pill every day for 28 days. One must always follow the correct intake order and maintain a specific time every day for taking the pills until the packet is completed.

Step 3: When a user takes dummy pills for the 7-day period, one will experience bleeding.

Step 4: The user should start with a fresh pill pack after completing the 1st pack, irrespective of whether bleeding continues or has stopped.

2. Tailored Regime

A user can also take combined pills as per tailored regimes suiting the specific needs and uniqueness of one’s health metrics. A tailored regime can include taking a combined pill for a stretch of 21 days and refraining for the next 5 days. It may also comprise taking a specific pill for a continuous period without any break in the schedule. 

An experienced medical practitioner should always be consulted for formulating a tailored regime. The steps one can follow in a tailored regime are given below.

One can start the pill at any stage of the oestrus cycle. However, it is always advisable to use additional contraception depending on the stage of one’s menstrual cycle. Furthermore, medical surveillance and guidance are mandatory for exceptions like miscarriage, short or abrupt menstrual cycle, abortion or after delivery. 

• 1st Day of Menstrual Cycle

If one starts to take the combined pill on the 1st day of the menstrual cycle, then the user will be protected from unwanted pregnancy right away. There is no need for other means of contraception in such a case.

• 5th Day of Menstrual Cycle – on or Before

If one starts the combined pill on or right before the 5th day of one’s menstrual cycle, the pill will protect from pregnancy as in the previous scenario. 

• 5th Day of Menstrual Cycle – After

If a user begins to take the combined pill after the 5th day of the menstrual cycle, the effectiveness of the pill will decrease. In this scenario, the pill will not be able to protect right away and it will be beneficial to use additional contraception till 7 days after using the pill.

The birth control pill or combined pill shows 99% efficiency if taken at the right dosage and by following a proper regime. This means that if a user forgets to take a pill for even one day, the efficiency drops. 

However, the pill causes changes in the hormonal balance of a woman’s body, and for most women, it becomes quite challenging to maintain the regime and perfect time of intake. This is the reason why out of 100 women, 9 women face unintended pregnancy every year. 

The reliability of the pill comes with consistency of usage, and one needs to intake it every day at the right time. This prevents fluctuations in hormone levels in a woman’s body and increases the pill’s efficiency.

The primary criteria that can lower the effectiveness of a combination pill or a birth control pill are an improper time of taking the pill and not following a regular routine. Factors like missed pill intake, consuming the pill at different times every day, improper regime and incorrect dosage all create hormonal imbalances in a woman’s body. 

This results in reducing the pill’s effectiveness to an extent where the pill may fail to avert pregnancy. Some other health conditions that can also reduce effectiveness are vomiting the pill out after intake or suffering from diarrhoea for a continued stretch of 48 hours after its intake.

It often takes a minimum of 7 days for a combined pill to be fully effective in stopping unintended pregnancy by altering the reproductive hormones of a woman’s body. During this period of time, it is advisable for a user to use an additional birth control measure (barrier contraceptives like condoms) to achieve the desired result.

Further, for controlling symptoms, namely, abnormal bleeding or acne, the pill needs to be taken for a stretch of 3-4 months to attain benefits. Also, the time when one has started to take the pill and the type of combined pill used are important factors that one should not ignore. 

• Progestin-Only Pill or POP

These pills (also known as ‘mini pills’) can be started at any time of one’s menstrual cycle or any day of a month. It helps to protect the user and starts to show efficiency after 2 days or 48 hours of consumption. During these 2 days, it is best if one combines the usage of the pill with an additional form of birth control measure like a condom.

An exception to this is a POP pill named Slynd. If the Slynd pill is taken on the 1st day of one’s menstruation, the user will be protected from pregnancy from that day itself. But if Slynd is started at any other time of menstrual cycle, it needs to be combined with barrier methods for protection for the next 48 hours. 

• Combination Pill or COC

If COCs are started within a period of 5 days from the 1st day of one’s period, then the pill protects from pregnancy from that very day. For example – If a user gets her period on a Saturday evening, then the pill will provide protection any time until the following Thursday evening. If that is the scenario, then COC will provide protection from the same day of its intake.

However, if a COC pill is started at any other time of one’s periodic cycle, then one needs to intake the pill for a continuous stretch of 7 days before getting protected. During these 7 days, one should use another birth control measure like condoms or barriers for ensured protection against pregnancy.

One can follow the 13 simple tips below to gain knowledge on how oral pills work and to ensure 99% efficiency.

Tip 1: One can follow the standard routine for pill intake, i.e., consuming 1 pill every day for a stretch of 21 days. This is followed by a break of 7 days when a user experiences bleeding. One needs to continue with the pill after the 7th day.

Tip 2: One can follow a tailored routine suiting one’s ease or convenience, i.e., taking pills with no breaks or short breaks in between. For this, one needs to consult with a healthcare practitioner.

Tip 3: One must consume the pill at a fixed time every day. If not taken at the right dosage or if one vomits the pill, misses a pill or suffers from diarrhoea, then they run the risk of getting pregnant.

Tip 4: Get educated about the effects of medicines on pills. Some medicines reduce the effectiveness of combined pills. A timely consultation with medical supervisors can help avert this.

Tip 5: One can take a combined pill to reduce associated problems of reproductive health other than pregnancy. These may be experiencing painful periods or heavy bleeding, endometriosis or premenstrual syndrome (PMS). However, doctor consultation is mandatory.

Tip 6: The combined pill may not be suitable if a user is above 35 years of age. Also, the pill may not be effective if a user smokes and has other associated health issues.

Tip 7: One must be knowledgeable on the minor side-effects of the pill, namely – headache, tenderness of breast, nausea or depression.

Tip 8: The pill only provides protection against pregnancy and not against any Sexually-Transmitted-Diseases or STDs. One must use a condom for such cases.

Tip 9: One must avoid myths related to knowledge and know that the pill holds a low risk of causing blood clots and cancer.

Tip 10: Research has shown that there are very low chances of any existing linkage between pill intake and obesity.

Tip 11: One must ensure that the pill is taken correctly to provide 99% efficiency in preventing pregnancy. This means that a combined pill should be taken at the right dosage and at the correct time every day after consultation with a medical practitioner.

Tip 12: One must remember that the combined pill will work best if started at the right stage of one’s menstrual cycle and if the pill is consumed every day. If taken in correct dosage, then there’s very little chance of getting pregnant.

Tip 13: One can use a birth control app to set reminders for taking the pills every day at the right time.

A birth control pill works by changing the reproductive hormone levels in a woman’s body to avert the process of ovulation. So, it helps to avoid pregnancy. However, STDs are caused by infectious agents like viruses or bacteria that are transmitted via infections during intercourse. 

Thus, the transmission of infection-causing agents cannot be prevented by using combination pills. Other birth-control measures like the usage of rings, patches or IUDs, though effective in avoiding pregnancy, do not provide protection against HIV and STDs. One will require other control measures in order to avert STDs. 

STDs can only be successfully prevented by avoiding anal, oral or vaginal intercourse or by using barrier methods of protection like condoms made up of latex.

Before starting with a specific birth control pill or regime, one must always take medical advice and visit a medical practitioner. This is to check whether any supplement or medicine which they intake in their daily life can act and deter the efficiency of the combined pill in preventing pregnancy.

A few such supplements and medicines are listed down below.

• Rifampin is an antibiotic that can reduce the pill’s effectiveness. This is not applicable to other antibiotics, and there are other antibiotics that do not have any effect on the pill’s efficiency.
• Griseofulvin is an antifungal medicine that can make a combined pill less effective. Other antifungal medicines do not produce the same negative effect on the pill.
• Certain medicines prescribed for treating HIV infections also reduce the effectiveness of birth control pills.
• Anti-seizure drugs or medicines which are used to prevent seizures or mental health disorders deter the effectiveness of combined pills.
• St. John’s Wort is a herbal medicine which is often used in treating menopausal symptoms, anxiety, depression, Attention-Deficit-Hyperactivity-Disorder (ADHD) etc. and lowers the effectiveness of the pill.

If the aforementioned medicines are taken by a user while on a pill, then it is advisable to use other contraceptives like condoms as an additional measure to protect against pregnancy. One can also opt for switching to other birth control measures if these aforementioned medicines are mandatory and need to be used for a prolonged time.

Apart from the hormonal birth control measure of using a combination pill, there are certain other non-hormonal measures that one may opt to prevent pregnancy. In a non-hormonal method, a woman’s hormonal balance is not affected. 

These alternatives to birth control are discussed below:

• Barriers – These methods create a physical barrier to prevent fusion of an egg and a sperm and, thereby, fertilisation. Some types of barrier methods are: diaphragm, cervical cap, sponge, copper IUD (Intra-Uterine-Device), spermicide, gel and condoms.
• Surgical Methods – Surgical processes or sterilisation methods are of two types – tubectomy and vasectomy. In the former, the fallopian tubes of a female are blocked to prevent the egg from reaching the uterus and, thereby, fertilisation. In a vasectomy, the tubes carrying sperm in a male reproductive system are sealed. 
• Behavioural Methods – Behavioural methods include outercourse and withdrawal methods.
• Family Planning – In family planning, the menstrual cycle is kept on track to prevent intercourse on days of ovulation, when a female body remains the most fertile. Also known as the rhythm method, it needs monitoring of body temperature, discharge and other physical parameters to avoid intercourse on such days.

This article provides a comprehensive idea of how birth control pills work. It also details the medications to avoid while using a birth control pill, the regimes to follow for 99% effectiveness, how long does the pill take to work and the types. 

Furthermore, the additional birth control measures one can adopt alongside the pills, as well as ideal alternatives for preventing STDs, have all been provided.