Dr. Meier's updates

Apr 23 2012

Medroxyprogesterone (The "Birth Control Shot") and Providing Milk for an Infant in the NICU: Evidence and Counseling Tips for Health Care Providers

A recent paper in Breastfeeding Medicine1 reviews the scientific basis for differing clinical opinions about the administration of injectable medroxyprogesterone (Depo Provera®, Pfizer, New York), often referred to as "the birth control shot," to new mothers during the maternity hospitalization.  The early use of this and other progestin-only contraception methods (including the "mini-pill" and the birth control "implant") have remained controversial because of the potential for these products to interrupt the successful initiation of lactation when administered in the early days after birth.  There is little disagreement among experts that the use of progestin-only birth control methods should not interfere with established lactation, e.g., when administered approximately 6 weeks post-birth.  The following frequently asked questions summarize some of the evidence surrounding the use of medroxyprogesterone  during the initial maternity hospitalization, and offer suggested counseling techniques for use with mothers who want to breastfeed or provide milk, especially those with early lactation risk such as breast pump-dependent mothers with infants in the NICU.


If medroxyprogesterone does not affect milk supply at 6 weeks, why should it affect lactation in the early days after giving birth?


The hormonal mechanisms that are necessary to maintain an established milk supply differ from those that bring about the initiation of lactation in the first few days after giving birth.2  The active ingredient in medroxyprogesterone is not likely to affect an established milk supply, but may interfere with the initiation of lactation.  The mechanisms for initiation of lactation are very well-studied in humans and other mammals, and are as follows.  In the early postpartum period, the milk-making cells inside the breast go through a series of step-by-step changes that allow them to make and secrete milk.  The main trigger for these breast changes is the rapid fall in progesterone that accompanies the birth of the placenta.  As  the progesterone falls to very low levels during the first days after birth, its inhibitory effect on prolactin (the milk making hormone) is removed, and under the influence of high prolactin concentrations, the breast can begin to synthesize milk.   The fall in progesterone is critical, because it allows prolactin to stimulate structural changes in the milk-making cells that bring about lactogenesis II (e.g., secretory activation, the milk "coming in"), and change the type of milk from colostrum to mature milk.  These changes in the breast must occur for the mother to initiate lactation and establish her initial milk supply.  In fact her milk supply will increase from about 15 mLs on day 1 to 500-600 mLs by days 4-7 postpartum. The primary concern about hormonal contraception is that the active ingredient in these methods is a synthetic form of progesterone, and giving progesterone to other mammals during the early post-birth period interferes with the establishment of lactation.2   This is why exogenous progesterone usually does not impact an established milk supply,  but can interfere with the initiation of lactation.  Basically, the biologic mechanisms that control these two processes are completely different.


What do the studies in this area show?


As detailed in the Breastfeeding Medicine article, the quality of the studies about early postpartum use of medroxyprogesterone is very poor.  Specifically, there has been no well-designed randomized study in which a large number of exclusively breastfeeding mothers has been assigned by chance to receive different contraception methods and then followed sufficiently with appropriate measures for determining the adequacy of the milk supply.  Additionally, no studies have included mothers of NICU infants who are breast pump dependent, or other women who have many documented risks for the establishment of lactation.  For example, It is known that mothers of premature infants experience a less coordinated transition to making milk, with respect to the step-by-step changes in the breast tissues described above.4  Many other women with lactation risk factors, but with non-NICU infants also experience delayed onset of lactogenesis II, including those with high BMI, insulin-dependent diabetes, pregnancy-induced hypertension and other conditions.5.  It is biologically more likely, but unstudied and not proved, that these mothers may be more susceptible to the prolactin-inhibiting effect of early medroxyprogesterone  administration. 


How should I interpret the findings from these studies?


In the absence of definitive studies, many health care providers argue that:  "There are no studies that show early medroxyprogesterone is detrimental, so therefore its use is acceptable and ethical".  However, as stated by Brownell et al1, the biological mechanisms for the initiation of lactation are established fact--not theories, and include the importance of progesterone withdrawal.  Thus, the burden of proof should be that early hormonal contraception use is safe with lactation, not the other way around.  This translates into:  "Until studies show otherwise, it is not acceptable or ethical to conclude that early medroxyprogesterone  administration is safe with respect to the initiation of lactation. 


How should this information be shared with families, especially those with NICU infants?


Families understand that some aspects of health care are controversial because studies are incomplete or show different results.  HCPs can present contraception choices within this framework, so that families have all of the evidence they need to make a decision that best reflects their personal priorities with respect to contraception and lactation. Just as it is unacceptable for the HCP to tell a mother that there are "no known lactation risks" to the use of medroxyprogesterone, it is also inappropriate to insist that  medroxyprogesterone will interfere with the initiation of lactation.  Until this question is answered with quality, definitive research, the HCP should focus on answering the mother's specific questions, and then allow her to choose whether the most effective contraception or the greatest assurance of lactation success is her personal priority.  To ensure this information is communicated accurately and consistently, a parent information sheet6  can be used to guide the HCP discussion, and can be left with the family for further reference. 





1.  Brownell EA, Fernandez D, Howard CR, Fisher SG, Ternullo SR, Buckley RJJ, Dozier AM.  A systematic review of early postpartum medroxyprogesterone receipt and early breastfeeding cessation:  Evaluating the methodological rigor of the evidence.  Breastfeeding Medicine 7: 10-18, 2012.


2.  Neville MC, Morton J, Umemura S.  Lactogenesis:  The transition from pregnancy to lactation.  Pediatric Clinics of North America 48: 35-52, 2001.


3.  Meier PP, Engstrom, JE, Janes JE, Jegier BJ, Loera F.  Breast pump suction patterns that mimic the human infant during breastfeeding:  Greater milk output in less time spent pumping for breast pump-dependent mothers with premature infants.  Journal of Perinatology doi:10.1038, 2011.


4.  Cregan MD, De Mello TR, Kershaw D, McDougall K, Hartmann PE.  Initiation of lactation in women after preterm delivery.  Acta Obstetricia et Gynecologica Scandinavica 81: 870-877, 2002.


5.  Hurst NM.  Recognizing and treating delayed or failed lactogenesis II.  Journal of Midwifery and Women's Health 52: 588-594, 2007.


6.  Birth Control Choices While You Provide Milk for Your Baby in the NICU.  Rush Mothers' Milk Club, Chicago, IL, (under development)


©Rush Mothers Milk Club, 2012.  All rights reserved

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