Table of Contents
- 1 Infertility associated with breastfeeding
- 2 Physiology of infertility associated with lactation
- 3 Differences between women
- 4 Contraceptive effectiveness of lactational amenorrhea
- 5 Guidance to mothers
- 6 In conclusion
- 7 References
Infertility associated with breastfeeding
Women who do not breastfeed have a rapid recovery of ovarian function, of ovulation and fertility. Usually the first ovulation occurs between the 4 and 8 weeks postpartum. In contrast, women who breastfeed have a period of amenorrhea and infertility that can last from two months to two or more years.
Breastfeeding as birth control. This period of infertility associated with breastfeeding has contributed significantly to space out births throughout the history of the human species. In part, the phenomenon of the population explosion is due to the decline in breastfeeding and its impact on fertility.
The clearest example is the one observed by anthropologists in the hunter-gatherers who lived in the Kalahari Desert in Africa. Since they didn’t have crops, they had no food to supplement the young children.
Therefore these were dependent on breastfeeding for their survival. In this population, breastfeeding and associated amenorrhea lasted more than four years, with the consequent separation between the pregnancies.
Also, puberty was later. Thus, women had only 3 or 4 children in their reproductive lives.
Infertility associated with breastfeeding still contributes significantly to those countries where most women breastfeed for long periods working as a population control factor.
However, the impact of breastfeeding on fertility has decreased in many places due to progress, changes in lifestyle and the need to study or work. These factors can interfere with breastfeeding and the frequency of the baby suction that is needed to maintain postpartum amenorrhea and infertility.
Physiology of infertility associated with lactation
The physiological mechanisms of infertility associated with breastfeeding are not known and all the variables that help to strengthen the association between suction and inhibition of ovarian function. We will briefly describe what you know, to better understand why suction is so important for maintaining postpartum infertility. Nipple suction has an inhibitory effect on the function of the hypothalamus and pituitary gland in terms of production of the hormones that control ovulation.
Without these hormones, the ovary does not produce a mature egg or progesterone, which is necessary to prepare the uterus to nest a fertilized egg. The woman does not have menses, which is called postpartum amenorrhea.
Suction determines an alteration of the pulsatile secretion of the hormone luteinizing hormone (LH) which is responsible for triggering ovulation. It is found in the blood in smaller amounts than those seen in women who are not breastfeeding.
Various mechanisms have been suggested to explain why this happens. There would be a transitory alteration of the hypothalamic centers that produce the factor that stimulates secretion of LH (GnRH) and a certain resistance of the pituitary to respond to the amounts available from this stimulating factor.
During suction, very high amounts of prolactin (PRL) are produced, which is the hormone in charge of milk production. It’s not clear if this hormone also influences the function of the hypothalamus, pituitary or ovary. Some think it might influence directly at this central level or that may alter the ovarian response to LH. Others believe it has no direct influence, because normal ovulatory cycles have been observed and also pregnancies in the presence of high levels of LRP.
Influence of suction
There is a very clear relationship between the way you nurse and the length of the period of postpartum amenorrhea:
- Women who are exclusively breastfeeding are more likely to remain more amenorrheic than those that add other foods to the baby. It is understood as exclusive breastfeeding when no other solid or liquid foods are given, although adding vitamins or small amounts of water or juice occasionally does not affect the duration of the amenorrhea.
- If supplements are introduced into the child’s diet, the suction power decreases to inhibit ovulation. There is a lot of research that confirms this effect. The first postpartum bleeding occurs earlier in mothers who supplement, with the consequent increased risk of pregnancy.
- The frequency of suctioning episodes is also very important for inhibition of the ovary. The more frequent the suctioning episodes, the more likely it is that woman remain in amenorrhea.
- Amenorrhea is longer in those populations where women breastfeed for long periods. However, the vast majority of women recover uterine bleeding before breastfeeding is stopped and it is not possible to predict how much to last the amenorrhea in a particular woman.
Alteration of the first menstrual cycle
Pregnancy during lactational amenorrhea is very rare in the first six months postpartum, even in women who ovulate before the first menstruation, because the first menstrual cycle is altered.
In most cases, the first ovulation is followed by a luteal phase insufficient to prepare the endometrium. This first luteal phase is shorter and has blood progesterone levels that are lower than in the luteal phase of women who are not breastfeeding.
The following menstrual cycles
The following menstrual cycles have many characteristics more normal. Luteal phase length and progesterone levels are similar to those of women who don’t breastfeed.
Therefore, fertility recovers quickly after the first menstruation postpartum. However, suction retains some of its inhibitory power, as the rates of pregnancy in women who are breastfeeding and who have periods are lower than in women who don’t breastfeed. Since this protection is inadequate, women who want to avoid a pregnancy should not postpone contraception beyond the first postpartum bleeding.
After six months postpartum
Women are more likely to ovulate before the first bleeding and that this first menstrual cycle is normal. Therefore, the limit for the use of lactational amenorrhea as a contraceptive has been set at the six months postpartum.
However, in some parts of the world, women have periods of very long amenorrhoea and their infertility lasts beyond six months.
Differences between women
It is important to bear in mind the differences that may exist between the various women and populations in terms of duration of lactation amenorrhea. We saw that in the hunter-gatherer amenorrhea can last for years. It’s still very long in some regions of Asia and Africa.
However, it tends to be shorter in Latin America. For example, studies in Chile show half of the women recover their menstrual bleeding and ovulation in the first six months postpartum, despite being in exclusive breastfeeding.
This duration of amenorrhea is important because women experience a sharp increase in the risk of pregnancy after the first bleeding, which should be clearly explained in counseling, as we’ll see later. It also has practical importance for strategies to be used by planning programs family members for postpartum women.
The number of suctioning episodes that is necessary to maintain amenorrhea may be different in different populations. A study in Scotland showed that the women do not ovulate in the first few months if they are breastfeeding more than 6 times in 24 hours. In contrast, the ICMER study showed that half of the women had the first postpartum bleeding at six months, despite breastfeeding at a frequency of similar or greater suction.
However, the ICMER study also supports the influence of suctioning episodes. It showed that a woman has half the risk of experiencing the first rule if you breastfeed more than 7 times in 24 hours compared to the risk you have of women who breastfeed at a low frequency.
The reasons for these differences are not well known. They could be due to different ways in which women breastfeed, to the influence of minor variations in frequency, to endocrine, metabolic or nutritional aspects of the mother or other factors that are not yet known. In ICMER studies, differences have been observed between women who experience a long duration of amenorrhea and those who experience a short duration of amenorrhea. These differences occur from the first few weeks after birth. Those who are going to have a long amenorrhea, have the lower estrogen and LH levels and a higher rise in prolactin after suction than those who will have short amenorrhea.
Contraceptive effectiveness of lactational amenorrhea
Lactational amenorrhea effectively protects women in the first six months postpartum, if they’re exclusively breastfeeding. Under these conditions, the rate of pregnancies is less than 1 per 100 women, which is comparable to more effective contraceptives.
This was discussed in depth at two meetings involving experts from many parts of the world. The agreement among these experts is known as the Consensus of Bellagio since the meetings took place there.
The method of lactation amenorrhea (LAM) has been called conditions that allow this level of contraceptive effectiveness to be achieved. It is important to introduce this option in family planning programs, as we will see when we talk about postpartum contraception.
Guidance to mothers
The following points are important for correctly informing women about the infertility associated with breastfeeding:
- The most important indicator that fertility has been restored during lactation is the first bleeding that appears after the period of amenorrhea. This is significant even if the woman is exclusively breastfeeding and in the first months after delivery. The probability of pregnancy increases significantly after the first postpartum bleeding. It is important to remember that this first bleeding may be rare and different from previous menses and that, even if it’s only for two or three days, should be considered as an indicator of fertility recovery. Therefore, the mother must be warned to pay attention to any bleeding or dripping.
- Another indicator of pregnancy risk is the introduction of artificial milk or other food in the child’s diet. This increases the likelihood of menstruation and fertility. It is possible to prolong amenorrhea if supplements are slowly introduced, maintaining a high suction rate. In any case, it is recommended not to introduce supplements in the first six months, unless it is indispensable for inadequate infant growth.
- The third risk indicator is the child’s age, since after 6 months a significant decrease in the contraceptive effectiveness of breastfeeding. In the first 6 months after birth, although some women ovulate before the first bleeding, the luteal phase is inadequate and pregnancy does not occur. Instead, after six months, the probability of ovulating before the first bleeding and this ovulation may be followed by a luteal phase with characteristics normal.
It is also important to remember that the way you breastfeed influences the duration of and amenorrhea. To prolong it, it is best to breastfeed exclusively and in free demand with a high frequency of suction episodes, maintaining at least a suction during the night as they should not be separated for more than 6 hours. This also contributes to better feeding and growth of the infant, allowing postpone supplements until after 6 months.
In practice, the answer to three questions allows us to estimate the risk of pregnancy from
the mother during the postpartum period and orient her:
- Has she had her first postpartum bleed?
- Is she giving supplements?
- Is your son or daughter more than six months old?
If NO: Inform her that she does not need another birth control method, but that you can start it if you want.
If the answer is yes: The woman is at greater risk of pregnancy, and the use of another method of contraception and to continue breastfeeding for the health of your child.
If the woman wants or needs to start another method of contraception, she should be given information on the methods best suited to the breastfeeding woman and the best time to start them.
The influence of breastfeeding on fertility varies in different communities and depends largely on how you breastfeed. Women who are in Exclusive breastfeeding with a high suction frequency have a lower risk of regaining ovarian function.
In the first six months postpartum, a woman’s risk of pregnancy in amenorrhea and exclusive breastfeeding is similar to that of contraceptive users modern. After the first postpartum bleeding, fertility recovers quickly, even if a high suction rate is maintained. The supplementation of the Being six months or more from delivery is also a risk factor for pregnancy.
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