Can I still get pregnant after taking birth control pills?

Most people who take birth control pills don’t know what their exact effects are. They just know that birth control pills can prevent pregnancy. In fact, birth control pills can only inhibit ovulation, making it difficult for sperm to penetrate, or change the way the uterus moves, but they do not necessarily prevent unwanted pregnancy. Today we will find out whether you can still get pregnant after taking birth control pills.

The main functions of contraceptives: inhibit ovulation and change cervical mucus, making it difficult for sperm to penetrate, or reduce the production of glycogen in the uterine glands, making it difficult for the blastocyst to survive, or change the activity of the uterus and fallopian tubes, hindering the transportation of the fertilized egg.

The mechanism of action is multi-faceted and multi-faceted, and varies depending on the ingredients, preparation, dosage and usage. For example, combined preparations of estrogen and progesterone mainly inhibit ovulation, small doses of progesterone mainly hinder fertilization, and large doses of progesterone mainly prevent implantation. The above classification of application mechanisms is relative.

1. Steroid hormones that mainly inhibit ovulation

After oral administration, the blood concentration of estrogen and progesterone increases, which inhibits the secretion of gonadotropin-releasing hormone in the hypothalamus through negative feedback. In addition, the sex hormones in the blood also have a direct inhibitory effect on the anterior pituitary, which can reduce the secretion of gonadotropin by the anterior pituitary, and the amount of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in the blood. Since the secretion of FSH is inhibited, the growth and maturation of follicles are hindered, there are no mature follicles for ovulation, and the estrogen peak before ovulation is also cancelled. Because the LH surge during the mid-cycle disappears, the ovulation process is inhibited.

2. Steroid hormones that mainly hinder fertilization

After taking small doses of progesterone orally, it changes the physical and chemical properties of cervical mucus and hinders fertilization. Progesterone can inhibit the secretion of cervical mucus, reducing the amount of mucus but increasing the viscosity and cell content, which is not conducive to sperm penetration, making it difficult for sperm to pass through, thereby hindering fertilization. When progesterone is dominant, sperm capacitation is inhibited and sperm loses its fertilization ability, thus affecting fertilization. Taking small doses of progestin continuously throughout the menstrual cycle can hinder fertilization. Its advantage is that it does not contain estrogen and has fewer side effects, but its contraceptive effect is worse than that of estrogen and progestin combination preparations, and the incidence of irregular bleeding is higher. Rarely used.

The human hypothalamus secretes gonadotropin-releasing hormone (GnRH). GnRH stimulates the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In women, FSH promotes the growth and development of ovarian follicles. Under the combined action of FSH and LH, the mature follicles secrete estrogen and progesterone. Both progesterone and estrogen levels in women's bodies drop to their lowest levels during menstruation. After menstruation ends, the secretion of these two hormones begins to increase. The first is that estrogen increases faster. Before ovulation, high estrogen levels can stimulate the pituitary gland to secrete LH directly or through the hypothalamus, leading to ovulation (positive feedback).

After ovulation, the progesterone content begins to reach its peak (luteal phase). At this time, due to the high levels of estrogen and progesterone in the blood, progesterone reduces the secretion of hypothalamic GnRH, thereby inhibiting ovulation and inhibiting the woman's own progesterone and estrogen secretion (negative feedback). Therefore, after ovulation, when progesterone reaches its peak, the estrogen and progesterone levels in a woman's body will begin to decline, and when they decline to a certain level, menstruation will occur. The so-called "safe period" includes the luteal phase. During the luteal phase, the level of progesterone in a woman's body is high, so she will neither ovulate nor become pregnant.

The above article has introduced in detail whether you can still get pregnant after taking birth control pills. Although the chance of pregnancy may be smaller, it does not mean that you will not get pregnant. There are also many female friends who get pregnant after taking birth control pills, so try not to use birth control pills excessively for contraception.