HOME

TheInfoList



OR:

Fertility while breastfeeding is controlled by the
hormonal A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required fo ...
effects induced by
breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that brea ...
during the
postpartum period The postpartum (or postnatal) period begins after childbirth and is typically considered to end within 6 weeks as the mother's body, including hormone levels and uterus size, returns to a non-pregnant state. The terms puerperium, puerperal peri ...
. Hormones associated with
lactation Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proce ...
and breastfeeding can inhibit processes necessary for conception. Because of the high variation of this process, breastfeeding is not recommended to be a method of contraception by medical providers, although correct use of breastfeeding as contraception, termed ''
Lactational Amenorrhea Method Lactational amenorrhea, also called postpartum infertility, is the temporary postnatal infertility that occurs when a woman is amenorrheic (not menstruating) and fully breastfeeding. Physiology Hormonal pathways and neuroendocrine control ...
'' (LAM), is as effective as hormonal contraceptive pills for the first six months after birth.


Reliability

Breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that brea ...
as contraception - the lactational amenorrhea method - has a failure rate of 2% with typical use, and 0.5% with perfect use. By
comparison Comparison or comparing is the act of evaluating two or more things by determining the relevant, comparable characteristics of each thing, and then determining which characteristics of each are similar to the other, which are different, and t ...
, condoms have a failure rate of 13% with typical use, and 2% with perfect use. Breastfeeding does not provide protection against STIs. Breastfeeding is not a sole method of postpartum contraception that is recommended by medical providers, because its effectiveness is variable. LAM is comparable in effectiveness to oral contraception. LAM is as effective as progesterone-only contraceptives when comparing perfect use, and much more effective than oral contraception with typical use. The factors that contribute to the reliability of using breastfeeding as a method of postpartum contraception are the amount and frequency of breastfeeding, the age of the baby, and whether they baby is exclusively breastfed or is partially formula fed or has started solids. To be effective, LAM requires the baby be less than six months old, exclusively breastfed, at least every four hours during the day and at least every six hours during the night. The time in which a
lactating Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...
woman does not
menstruate Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of ho ...
is called
lactational amenorrhea Lactational amenorrhea, also called postpartum infertility, is the temporary postnatal infertility that occurs when a woman is amenorrheic (not menstruating) and fully breastfeeding. Physiology Hormonal pathways and neuroendocrine control ...
.
Amenorrhea Amenorrhea is the absence of a menstrual period in a woman of reproductive age. Physiological states of amenorrhoea are seen, most commonly, during pregnancy and lactation (breastfeeding). Outside the reproductive years, there is absence of menses ...
is the medical term that means “no menstruation.” If a woman is not menstruating, her uterine lining is not proliferating and shedding. The purpose of uterine lining proliferation is to provide a favorable environment for a potential fertilized
zygote A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellula ...
. A thick uterine lining is rich in grooves and blood vessels. The grooves increase the surface area inside the
uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The uter ...
, giving the fertilized zygote many different options for locations to implant. Blood vessels provide the implanted zygote with the sufficient amount of nutrients necessary for its development. Without uterine proliferation, implantation is extremely rare. The length of time in which a postpartum woman does not
ovulate Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized ...
is another factor. During ovulation, an egg develops, leaves the
ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...
, and travels down the
fallopian tube The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In ot ...
. There, it will most likely get fertilized if sperm cells are present. If ovulation does not occur, there is no egg present to be fertilized and become a developing zygote. Hormones present during breastfeeding can inhibit ovulation and uterine proliferation. The level of inhibition is highly variable in potency and is not uniform from woman to woman. Time since delivery contributes to the fertility of a postpartum woman as well. There is a direct relationship between time and fertility. As time increases, fertility also increases. This time can vary between individuals. This is why medical providers do not recommend using breastfeeding as a primary method for contraception. Other contraceptive use contributes to postpartum fertility as well. Medical providers will often recommend that sexually active postpartum woman be on some form contraceptive to avoid a subsequent pregnancy if desired.


Physiology

During pregnancy, levels of
estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activ ...
and
progesterone Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the major ...
are high and stimulate the production of
dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% o ...
. Dopamine inhibits the production of
prolactin Prolactin (PRL), also known as lactotropin, is a protein best known for its role in enabling mammals to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans. Prolactin is secreted from the p ...
. Because of this, prolactin is not produced during pregnancy. After childbirth, levels of estrogen and progesterone plummet, no longer stimulating the production of dopamine. Without dopamine present, prolactin's production is no longer inhibited. Both prolactin and
oxytocin Oxytocin (Oxt or OT) is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. It plays a role in social bonding, reproduction, childbirth, and the period after childbirth. Oxytocin ...
are needed for breastfeeding to occur. Oxytocin secretion is stimulated by
suckling Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that brea ...
. Suckling sends sensory input to the
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
where higher brain centers block dopamine and release oxytocin. The presence of oxytocin triggers the secretion of prolactin. Prolactin regulates the production of milk and delivery of that milk into the alveoli of breast tissue where it waits to be excreted. Oxytocin regulates the excretion of milk by targeting the layer of smooth muscle cells that surround the alveoli, causing them to contract. As this muscle contracts, milk is forced out of the alveoli, through ducts, and out of the breast via the nipple. The prolactin that is being secreted during one round of feeding is making milk for the next round of feeding. Oxytocin is expelling milk that was made during the last feeding. A breastfeeding mother's fertility is decreased because higher amounts of prolactin inhibit
GnRH Gonadotropin-releasing hormone (GnRH) is a releasing hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. GnRH is a tropic peptide hormone synthesized and released ...
through a direct relationship. The less prolactin there is secreted, the less inhibition occurs. Inhibition and fertility have an inverse relationship. The less inhibition that occurs, the higher the fertility rate will be. If there are fewer suckling events, there will be less prolactin production. If suckling ceases, prolactin levels will return to those of a non-pregnant woman.


Importance

If breastfeeding did not have any effect on fertility, then newly postpartum women would have an increased likelihood of getting pregnant. If they were to become pregnant again within the period of time in which they are breastfeeding their newborn, their next pregnancy would inhibit the production of milk as explained above. Breastfeeding's inhibitory actions reduce the likelihood of a subsequent pregnancy.


References

{{Reflist Chao, S. "The Effect of Lactation on Ovulation and Fertility." ''Clinics in Perinatology''. U.S. National Library of Medicine, Mar. 1987. Web. 21 Nov. 2019 McGregor, James A. "Lactation and Contraception." ''SpringerLink''. Springer, Boston, MA, 01 Jan. 1983. Web. 21 Nov. 2019. Planned Parenthood. "Breastfeeding as Birth Control: Information About LAM." ''Planned Parenthood''. N.p., n.d. Web. 21 Nov. 2019. Shaaban, Mamdouh M. "Contraception with Progestogens and Progesterone during Lactation." ''The Journal of Steroid Biochemistry and Molecular Biology''. Pergamon, 17 Jan. 2003. Web. 21 Nov. 2019. Breastfeeding