Last update Dec. 26, 2020
Normal fertility cycle (ASRM 2018 and 2012):
The gonadotroph cells in the anterior part of the pituitary gland secrete two gonadotrophin hormones: the follicle stimulator, follitropin or follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The FSH regulates pubertal maturation. In women, it makes the ovarian follicles that secrete estrogen grow as the egg they contain matures. A surge of hypophyseal LH causes the follicle to break and release the egg.
The egg is fertilized by a sperm in the fallopian tube and ends up nesting in the endometrium, conveniently prepared by the ovarian follicle estrogens with the ovule and the progesterone from the residual follicle or corpus luteum.
In assisted reproduction treatments (ART) for infertility, two issues must be taken into account:
1. THE POSSIBLE EFFECTS OF ART ON THE INFANT OR ON THE CURRENT BREASTFEEDING:
The various techniques used in the ART process (MedlinePlus 2019, ASRM 2018 and 2012): intrauterine insemination, in vitro fertilization, ovule collection, gamete or embryo transfer, etc., are physical-mechanical procedures that can not cause alterations in the infant or breastfeeding. The possible anesthetics used to apply them are compatible with breastfeeding.
However, two ART techniques use medication:
- for controlled ovarian stimulation (COS), clomiphene or letrozole are used and if they fail, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to mature the follicle and human chorionic gonadotropins and human menopausal gonadotropins (HGC and HMG) to cause ovulation. Gonadotropin-releasing hormone (GnRH) agonists and antagonists can be used to control that stimulation.
- Progesterone and estrogens are used to favour the nesting process.
Many of these drugs are found naturally in the body, have high molecular weight and protein nature, so they do not trasfer into breastmilk in significant quantities and are not absorbed in the intestine of the infant when ingested. It has not been proven that they reduce milk production.
They can be consulted one by one by clicking on the ones that appear at the end of this entry.
In general, they do not interfere with breastfeeding and do not affect the infant, who in these cases is usually older than 6 months and even 1 or 2 years old.
2. THE POSSIBLE INTERFERENCE OF CURRENT BREASTFEEDING WITH ART:
Breastfeeding, especially when frequent, could have a negative effect on ovulation. This is the main reason why assisted reproduction services recommend stopping breastfeeding before starting treatment which is usually emotionally costly as well as often from a financial perspective.
To date there is no published evidence that breastfeeding interferes with infertility treatments.
3. THE POSSIBLE EFFECTS ON THE BREASTFEEDING OF THE BABY BORN AFTER AN ART:
In vitro fertilization treatments are not associated with a lower frequency of initiation or shorter duration of breastfeeding (Purtschert 2020).
A whole series of data should be taken into account:
- Breastfeeding mothers have periods of amenorrhea and infertility of between two months to two or more years (Diaz 1990), but it is also true that pregnancies occur in breastfeeding mothers.
- Exclusive breastfeeding and frequent suckling are essential for maintaining amenorrhea. Once the first postpartum menstruation appears, fertility is restored, although the frequency of pregnancy is lower in menstruating mothers who are breastfeeding (Diaz 1990).
- Breastfeeding mothers have high levels of prolactin and FSH and low levels of inhibin (Kremer 1994), estradiol (Burger 1994) and LH (Glasier 1983).
- The exact mechanism by which breastfeeding hinders ovulation is not known, but it does not seem to depend on the increase in prolactin, which is only at maximum at the beginning of breastfeeding (Battin 1985), but on the suppression of the pulsatile rhythm of LH secretion (McNeilly 2001, Tay 1991), which is complete during early breastfeeding and only partial during late breastfeeding (Kremer 1991). For some reason, the ovary does not respond to FSH and does not produce estrogen (Bonnar 1975).
Stimulus on the breasts has to be very frequent for this to happen (McNeilly 2001) and breastfeeding, with regard to older infants, is no longer exclusive nor as frequent.
There is no published data that demonstrates that breastfeeding is incompatible with assisted reproduction processes.
In the last 10 years, four mothers have told us that they had continued to breastfeed while on ART, which included COS, without there being problems for breastfeeding or the infant and they had a successful pregnancy.
You can see and hear personal testimonies at Bernal EM 2014.
A lower frequency and duration of breastfeeding has been observed in mothers who conceived by ART, partly secondary to the frequent association with caesarean section, multiple pregnancy and prematurity (Barrera 2019, Wiffen 2016, Cromi 2015, Fisher 2013).
Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.
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