Mostly used birth control pills are a hormonal type of tablets like Ovral or Ovral L which contain two synthetic hormones, named estrogen and progestin. These hormones are of different generation and quantity in each brand and type of birth control pills. Therefore, it is necessary to know what type of birth control suits you to get the maximum effectiveness.
These birth control pills prevent pregnancy through two key ways-
- Mainly by prohibiting ovulation
- Or by obstructing the sperm’s travel towards the egg by thickening the cervical mucus
In case no egg is released, then there is nothing that the sperm can fertilize, so the woman taking the pill cannot get pregnant. The two synthetic hormones in the pills – estrogen and progestin- when introduced in the system- stabilize the woman’s naturally occurring hormone levels. This prevents estrogen from summiting mid-cycle.
In absence of this estrogen shot, the pituitary gland does not expel other hormones that typically cause the ovaries to discharge developed eggs.
Specifically, the synthetic estrogen works in a particular manner to prevent pregnancy
- Firstly, it halts the pituitary gland from creating luteinizing hormone [ LH] and follicle stimulating hormone [ FSH] to avoid ovulation.
- It also backs the uterus lining [ endometrium] to prevent breakthrough bleeding between the cycles.
All the while, synthetic progestin works to:
- Stop the pituitary gland from producing Luteinizing hormone [ LH] in order to prevent egg release.
- Make the endometrial lining [ uterine] inhospitable to a matured egg
- It partially limits the sperms’ ability to reach and fertilize the egg.
- It thickens the cervical mucus to deter the sperm’s movement [ although this effect may not be crucial in preventing the pregnancy].
How do the hormones in birth control pills act together?
A continuous loop of hormones exists in a female body acting on various levels. LH and FSH are two hormones that are produced in the brain that act on the uterus and the womb. FSH progressively thickens and prepares the uterine lining of the womb to receive the fertilized egg, while LH encourages bursting of the ovary mid-cycle to secrete the egg for fertilization.
When synthetic progestin and estrogen combo are administered they block the release of gonadotrophic hormones like LH and FSH which prevents ovulation.
Further, the lining of the womb is made unnaturally ripe/ soggy which disallows proper implantation.
The natural existing mucus at the mouth of the uterus or cervix become s unusually thin during mid-cycle due to LH. As the mucus thickens it prohibits sperm movement, which decreases the number of fatigued sperms that are an unlikely candidate for normal reproduction.
The dual presence of estrogen and progestin in the birth control makes combination birth control pills ideal to prevent ovulation and stopping fertilization and implantation.
When such a combination of hormones is administered for a period of 21 days, then discontinued abruptly it causes the uterine lining to shred, which normally ripens in the presence of hormones. Such artificial bleeding cause the absence of hormones at the end of a cycle is called as “withdrawal bleeding”.
Categorised in: Birth Control Pills
This post was written by Marcella