Oral contraceptives are considered compatible with breastfeeding. However, it is necessary to make some considerations about it:
There is very limited evidence about the influence of oral contraceptives on breastfeeding from randomized controlled clinical trials, which are generally of poor quality and insufficient to establish significantly an effect of contraception, if any, on the quality and quantity of milk.
Different research advocate for the use of oral contraceptives containing only progestin. Some experts believe that the use of norgestrel can stimulate lactation and is not associated with differences in the content of the milk. The use of 75 mcg/day of desogestrel did not change the composition or the amount of breast milk, nor did it affect the development and growth of the child. However, the behavior of progestogens is not uniform.
Levonorgestrel was associated with a decrease in the volume of milk, but did not lead to differences in weight development or head circumference of children. The same work pointed out the appropriateness of initiating contraception with progestogen only when the infant is less than 6 months of age, on the basis that these drugs do not seem to affect the volume of milk, its composition and that lacks of effects on the infant.
Some authors consider the combined oral contraceptive contraindicated during breast-feeding because estrogen may suppress milk secretion or reduce the quantity and quality of breast milk with decreased protein content.
One trial in 250 nursing mothers treated with progestogen contraceptives showed that, in addition to have their children similar growth that the control group, have a lower perception of decreased milk secretion at 5th and 6th month of follow up.
The lack of robust evidence on this subject has led some authors to not discourage the use of combined oral contraceptive during lactation, considering a reasonable alternative and scientifically justified, while is mandatory warn of the possible consequences of the passage of hormone through milk. They recommend that be used the lowest dose possible and not before the baby gets two or three months of life. The pill would be ingested at the beginning of the longest pause between breast feeds, to minimize the intake of hormone, allowing the extension of the suck time to offset any reduction in milk flow.
It could be argued against the use of contraceptives that breastfeeding is itself a form of contraception. The problem is that this method does not allow to know when breastfeeding has ceased to be effective as a contraceptive and women become fertile again, and which offers no sure sign about it. Breastfeeding is associated with a lower pregnancy rate at 2% for the first six months of life the infant, which in some cases is clearly inconvenient.
Although oral contraceptives are generally considered quite safe, some alterations have been reported in breast-fed infants whose mothers took oral contraceptives simultaneously:
An infant of three weeks showed gynecomastia after 12 days of taking the mother a combined oral contraceptive containing mestranol (100 mcg) and norethynodrel (2.5 mg). The disorder disappeared after four weeks of stopping treatment [1,2]. Another infant 18 months of age, whose mother used a combined oral contraceptive containing 150 mcg of d-norgestrel and 30 mcg ethinyl estradiol for three months, presented; breast enlargement disappeared after six months of disruption of breastfeeding.
As it is known, progesterone stimulates the growth of breast tissue, while estrogens stimulate ductal growth.
We have described a rare case of major clinical and hematologic effects of folate deficiency in an infant of 10 months old whose mother took an oral contraceptive.
Decreased weight development:
Several observations reported decreased weight of breast-fed infants compared to controls. In one of them shows that the children of mothers treated with oral contraceptives showed at 61 and 91 days after birth lower absolute average of weight and lower daily weight gain during the first month that controls.
Other studies show results consistent with the above. In one of them, the group receiving oral contraceptive therapy maintained a lower percentage of full breastfeeding from six months and reduced weight gain during the fourth month, statistically significant, although there was no difference at the end of first year, nor were detected side effects. The authors conclude that oral contraceptives showed a moderate inhibition of breastfeeding when initiated at 90 days postpartum.
The weight gain in babies from the group of mothers treated with oral contraceptives was significantly lower than in the control group, despite the increase in caloric supplementation administered to these children. The duration of breastfeeding also decreased statistically significantly. This effect was more pronounced in primiparous compared with mothers who had previously breastfed successfully.
In some cases, the socioeconomic and cultural conditions amplify the effects of contraceptives to reach worrisome results. A clinical trial conducted in Egypt showed that children of mothers who received a combined oral contraceptive (Lyndiol 2.5) or an injectable contraceptive (Deladroxate) recorded weight values ??below the 10th percentile during the first four weeks.
Despite the above, most of the findings of clinical trials reflect the absence of significant effects of oral contraceptives on well-nourished mothers and adequate sociocultural situation. A long-term follow-up of infants whose mothers received a contraceptive containing 50 mcg of ethinyl estradiol showed no differences compared with the controls on disease incidence, behavioral or intellectual development during follow-up period of eight years. No oral contraceptive studied was associated with significant differences in weight or milk's fat or in the rate of discontinuation of breastfeeding due to lack of weight development.
Have been described following alterations of breastfeeding in mothers who received oral contraceptives during it:
Shorter duration of breastfeeding:
In a study of long term follow up, it was found that mothers treated with hormonal contraception, breastfeed a time period significantly shorter than controls, although no differences in weight gain and height of infants with respect to controls. This phenomenon is noticeable even at six weeks of life. In another trial, women using combined oral contraceptives, unlike the controls, experienced a reduction in the volume of milk within six weeks of starting treatment. After 18 weeks of taking combined oral contraceptives, patients experienced a 41.9% decrease in the volume of milk produced, compared with only 12.0% reduction in those who received oral progestogens as a contraceptive, while reducing the volume of milk was only 6.1% in controls without hormone treatment.
Contraceptive steroids may inhibit lactation, especially if the woman has a poor nutritional status or the contraceptive is started early after birth, ie before the start of the second month of life of the infant.
Changes in milk composition:
Changes in milk composition induced by contraceptives are controversial. Some authors find significant changes in protein concentration in milk. These changes, as well as the amount of milk were considered irrelevant from the nutritional point of view, although significant impact could be observed in mothers with poor nutritional status, by varying the magnitude of changes depending on the component in question. Changes in the daily volume of milk were considered within the normal range without nutritional significance. However, it was observed significant negative effects in malnourished mothers. Another study found a significant decrease in the quantity of milk, the total energy content and large changes in milk composition in patients with combined contraceptives.
Other studies, however have shown conflicting results with previous ones. After adjusting the data for groups of patients investigated were not found significant effects on the total amount of protein, fat, lactose and caloric value. A combined pill and another containing only progestin did not alter the total lipids in milk.
Low dose progestins have shown a significant decrease in the amount of fat and calcium in milk, but surprisingly, the addition of 10 mcg of estrogen resulted in a composition similar to that of controls.
Hormone excretion into milk:
A study of two volunteer patients allowed to evaluate the amount of radiolabeled ethinylestradiol sulfonate excreted in the milk. At day 9 were collected on 0.0012% and 0.03% respectively of the amount administered. The transfer rate of the plasma estradiol milk is estimated less than 10%.
D-Norgestrel transferred with 600 ml milk has been estimated at 0.15-0.30 mcg with 150-250 mcg daily doses of the substance, corresponding to 0.1% of the administered dose. Other authors place the transfer rate within a still modest level but higher than the previous reference of about 1:10. For the case of drospirona, progestogen of the contraceptive Yasmin, it is estimated that the daily dose offered to the infant is 3 mcg. Megestrol reaches a total dose 2 mcg in an infant with 5 kg which receives 600 ml of milk a day,. This amount represents 0.1% of the maternal dose. Commercial preparations containing cyproterone (Diane 35 and others) can transfer 1 mcg/kg daily to a baby. Medroxyprogesterone was detected in milk in a 1:1 ratio with respect to plasma. To the contrary, norethisterone found in milk at a ratio of 1:10 with respect to the plasma.
The desirable to administer combined oral contraceptives should be weighed against potentially reduction of the time of exclusive breastfeeding as well as production of a slight reduction in the amount of milk, which in the case of well-nourished mothers and probably adequate sociocultural level is irrelevant, but could lead to important risk situations in mothers with poor nutritional status. Above are mentioned ways to minimize the passage of hormone to the milk and partially offset the reduction in milk secretion.
Unless it can be to have better evidence in future, contraceptive treatment in nursing mothers should be based only in contraceptive of progesterone compounds, either by mouth or by injection or implant. The latter two should be used only if there is a history of good tolerance of women.
When deciding contraceptive therapy should be noted that there is an increased incidence of thromboembolic processes in the immediate postpartum period, which can be influenced by oral contraceptives.
Warning of the manufacturer:
If you are breastfeeding, consult your doctor before taking oral contraceptives. Some of the drugs passed to the baby through the milk. Have been reported some adverse effects on the child, including yellowing of the skin (jaundice) and breast enlargement. In addition, oral contraceptives may decrease the amount and quality of milk. If possible, do not use oral contraceptives while breastfeeding.
You should use another method of contraception since breastfeeding provides only partial protection against pregnancy and this partial protection decreases significantly as you breastfeed for longer periods of time. You should consider starting to take oral contraceptives only after you have completely stopped breastfeeding your baby.