Clomid/ClomifeneAdditional information added 09/06/19 – opinions on the safety of clomid vary between professionals / sources.
For clarity, historically our group has always been of the opinion that clomid can be taken safely during breastfeeding. This has been based on a collection of information sources. The group is still of this opinion, but strongly suggests that you read all of this information and make your own informed choice.
Previously, discussion on the Hale infant risks forums has tended to conclude that clomid is safe during breastfeeding, historical posts include:
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/other-uncategorized-medications/743-clomid-while-nursing-16-month-old
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/medications-and-mothers-milk/739-clomid-while-breastfeeding
It seems that recently, within the infant risk forums, Dr Thomas Hale has taken a far more cautious stance than previously, and has advised against taken this medication during breastfeeding. This is detailed in this link:
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/other-uncategorized-medications/12406-clomid-repost
We believe that the forums are answered by several people; Hale and his team which might explain some of the disparity between what different individuals have said. However he is clearly now saying that based on studies of rodents, clomid should not be taken during breastfeeding.
This does appear to be a new stance contrary to other evidence based sources, summarised as follows:
Briggs, Freeman & Yaffe say:
there is no human data, and no reports describing the use of clomid during lactation have been located. Based on the fact that studies in rodents have shown that it shouldn’t be used during pregnancy they have concluded that the characteristics of the drug suggest there could be a clinical risk to a nursing infant. They also cite reduction of supply.
Doctor Hales book still says:
that there is limited data regarding clomid, and it could be hazardous. It cites studies that showed suppression of early lactation by inhibiting supply, however it does not report any transfer or effect on infants.
Kellymom says:
That clomid is safe based on ‘personal communication’ with Dr Thomas Hale: https://kellymom.com/nursingtwo/resources/ttc-while-bf.pdf
E-lactancia says:
That clomid is low risk, and classified as moderately safe. It says that there is no published data on its excretion in breast milk. But that it’s high volume of distribution makes the transfer to milk in significant quantities unlikely, although its long half-life could facilitate it: http://www.e-lactancia.org/breastfeeding/clomifene-citrate/product/ We have contacted e-lactancia to see if the they would like to comment.
Since Doctor Hales stance appears to have changed we have made contact with the following experts:
Wendy Jones said:
It is worrying that Hale is saying this. She did say that his book hasn’t changed and nor has lactmed, but that the only real studies done were in relation to milk suppression and not transfer into milk. I will update this section as/when she comes back.
Jack Newman said:
‘I do not believe that clomiphene (Clomid) is risky during breastfeeding. Letrozole is considered a problem, but I have seen any new evidence or reason why clomiphene should now be considered risky during breastfeeding, especially as breastfeeding mothers are usually using it for a short time (about a week). Like almost all medications, clomiphene gets into the milk in minuscule amounts at all. Click and read: http://ibconline.ca/maternal-medications/However, I will check around and see if there is new information and get back to you soon’
Rodney Whyte said:
That there isn't enough information to say categorically that Clomid is a safe drug to continue while feeding as it is orally bio-available, small doses can pass through to breast milk and we don’t know what that might mean for an infant.
However he did feel that Clomid has limited potential for harm and would be ok to take while breastfeeding depending on your situation:
- He DOES NOT recommend Clomid for those with breastfeeding child under 12 months old as they are feeding primarily for nutrition.
- If your child is 12-24 months of age it would be situation depending on number of feeds and how much child is breastfeeding for nutrition as it can be hard to tell.
- If child is over 24 months he was much more comfortable recommending Clomid as most breastfeeding at this point is for comfort.
- Drug metabolism: Clomid peaks at 6 hours and has a half life of 5-7 days. You need to allow for 4 half lives (20-28 days) to occur before the drug is sufficiently cleared of mother’s system.
For an example: If you are taking 100mg of Clomid for 7 days you should be fine to take it in consecutive cycles as there will be at least 21 days in between taking Clomid again, (as it means that the half life allows the previous dose to completely leave your system)
An example scenario: Baby girl (aged 2) will feed in the morning, pre nap and before bed at night, then anywhere from 2-10 times a night. He felt confident that as baby was feeding for comfort rather than nutrition if I needed Clomid it would be ok.
UKDILAS have said:
We have looked at the properties of Clomid in order to make a risk assessment as there is no information on the use of Clomid during breastfeeding.
- Clomid half life is 5-7 days and the drug may be present in mother’s system up to 35 days after it has been stopped. This increases the likelihood of Clomid passing into breast milk especially with repeated consecutive cycles as it is small enough to be expected to pass into breast milk however pharmacokinetic properties suggest that any passage would be minimal. Therefore it is reasonable to conclude that although Clomid will pass into breast milk it will be in small quantities.
- Despite there being no evidence to confirm safety, there is also no evidence of harm or any adverse effects after exposure via the breast milk. Anecdotally, Clomid has been used in the breastfeeding population for many years, without any untoward effects being reported. Even at normal therapeutic doses, Clomid rarely causes side-effects in the women who take it. We do not know whether there are any longer term effects on infant exposure to this, but to date there has been nothing to suggest that there would be.
- Our recommendation is not age specific to the infant or dependant on the amount or frequency of feeding. Although these factors may influence how much of the drug the infant is exposed to, and how they handle it, these differences are not considered significant enough to alter the advice.
- The normal course length for Clomid is 5 days and shortening this would not limit exposure of the drug due to the long half-life. It may also not be a clinically suitable option to reduce the strength or course. Waiting 6 hours after the dose would also not make a significant difference either, again due to the long half-life of the drug. We would therefore advise that breastfeeding continues as normal.
- Clomid is not usually recommended during the first weeks postpartum due the risk of decreased milk production but this is unlikely to be relevant in a mother with established breastfeeding.
- Overall, there is no information available for the use of Clomid during breastfeeding. However, there is also no information available to suggest drug exposure as a result of breastfeeding causes harm to infants, and based on the properties of the drug, the amount in breast milk is likely to be minimal. Therefore, breastfeeding can proceed with caution in women who are taking Clomid with close monitoring of the infant for side effects such as gastro-intestinal disturbances, flushing and poor feeding.
In Conclusion:
What we know is that clomid assists ovulation by stimulating the release of pituitary gonadotropins, FSH and LSH. We do not know how much it passes into milk as this has not been studied.
It is worth considering that with any medication that does transfer to milk in small doses, with an older infant, a mum who’s milk supply is far lower, will not be likely to be transferring a high dose - particularly when considering the likelihood of further supply reduction from this type of medication:
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/11291-clomid-while-breastfeeding
It is also worth remembering that original discussion on this subject stated that levels were highest after around 6 hours, so you may want to consider timing your feeds/doses:
https://www.breastfeedingbasics.com/qa/can-clomid-help-get-pregnant-im-nursing
However troublesome the change in stance is, we must acknowledge that Hale as one of the leading specialists does not seem to think this should be taken. It should be noted however that he appears to place very little value on breastfeeding over the age of 18 months - much less than the other leading medication in lactation specialists. This may contribute to his advice.
In the meantime, we would suggest that you read this post and links thoroughly, ensuring you review the information provided at source before making a decision about your treatment. Dependant on your location, you may wish to consider contacting one of the sources above (Wendy Jones, UKDILAS, Rodney Whyte or E-lactancia) to discuss your own circumstances.
Please remember that this is only one specialist, it is well worth considering the full range of information without coming to a panicked decision. Many members over the last four years have said their fertility specialist / consultant has said clomid is safe to take, and many, many members have taken it over the past four years that the group has been running with no known ill effect.
If anyone is in the US and having done their reading decides that they are happy to go ahead and take it, and would like to help out with further research to benefit other mums, it is worth contacting Hales Clinical Research Center on 806-414-9742, as he has indicated that he would be willing to study milk samples.
As a final reminder, for anyone who is worried about the information from Hale and does wish to consider weaning or temporarily stopping please seek support from a breastfeeding professional before doing so.
For clarity, historically our group has always been of the opinion that clomid can be taken safely during breastfeeding. This has been based on a collection of information sources. The group is still of this opinion, but strongly suggests that you read all of this information and make your own informed choice.
Previously, discussion on the Hale infant risks forums has tended to conclude that clomid is safe during breastfeeding, historical posts include:
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/other-uncategorized-medications/743-clomid-while-nursing-16-month-old
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/medications-and-mothers-milk/739-clomid-while-breastfeeding
It seems that recently, within the infant risk forums, Dr Thomas Hale has taken a far more cautious stance than previously, and has advised against taken this medication during breastfeeding. This is detailed in this link:
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/other-uncategorized-medications/12406-clomid-repost
We believe that the forums are answered by several people; Hale and his team which might explain some of the disparity between what different individuals have said. However he is clearly now saying that based on studies of rodents, clomid should not be taken during breastfeeding.
This does appear to be a new stance contrary to other evidence based sources, summarised as follows:
Briggs, Freeman & Yaffe say:
there is no human data, and no reports describing the use of clomid during lactation have been located. Based on the fact that studies in rodents have shown that it shouldn’t be used during pregnancy they have concluded that the characteristics of the drug suggest there could be a clinical risk to a nursing infant. They also cite reduction of supply.
Doctor Hales book still says:
that there is limited data regarding clomid, and it could be hazardous. It cites studies that showed suppression of early lactation by inhibiting supply, however it does not report any transfer or effect on infants.
Kellymom says:
That clomid is safe based on ‘personal communication’ with Dr Thomas Hale: https://kellymom.com/nursingtwo/resources/ttc-while-bf.pdf
E-lactancia says:
That clomid is low risk, and classified as moderately safe. It says that there is no published data on its excretion in breast milk. But that it’s high volume of distribution makes the transfer to milk in significant quantities unlikely, although its long half-life could facilitate it: http://www.e-lactancia.org/breastfeeding/clomifene-citrate/product/ We have contacted e-lactancia to see if the they would like to comment.
Since Doctor Hales stance appears to have changed we have made contact with the following experts:
Wendy Jones said:
It is worrying that Hale is saying this. She did say that his book hasn’t changed and nor has lactmed, but that the only real studies done were in relation to milk suppression and not transfer into milk. I will update this section as/when she comes back.
Jack Newman said:
‘I do not believe that clomiphene (Clomid) is risky during breastfeeding. Letrozole is considered a problem, but I have seen any new evidence or reason why clomiphene should now be considered risky during breastfeeding, especially as breastfeeding mothers are usually using it for a short time (about a week). Like almost all medications, clomiphene gets into the milk in minuscule amounts at all. Click and read: http://ibconline.ca/maternal-medications/However, I will check around and see if there is new information and get back to you soon’
Rodney Whyte said:
That there isn't enough information to say categorically that Clomid is a safe drug to continue while feeding as it is orally bio-available, small doses can pass through to breast milk and we don’t know what that might mean for an infant.
However he did feel that Clomid has limited potential for harm and would be ok to take while breastfeeding depending on your situation:
- Duration of taking Clomid medication
- Age of your child and if breastfeeding for nutrition or comfort
- He DOES NOT recommend Clomid for those with breastfeeding child under 12 months old as they are feeding primarily for nutrition.
- If your child is 12-24 months of age it would be situation depending on number of feeds and how much child is breastfeeding for nutrition as it can be hard to tell.
- If child is over 24 months he was much more comfortable recommending Clomid as most breastfeeding at this point is for comfort.
- Drug metabolism: Clomid peaks at 6 hours and has a half life of 5-7 days. You need to allow for 4 half lives (20-28 days) to occur before the drug is sufficiently cleared of mother’s system.
For an example: If you are taking 100mg of Clomid for 7 days you should be fine to take it in consecutive cycles as there will be at least 21 days in between taking Clomid again, (as it means that the half life allows the previous dose to completely leave your system)
An example scenario: Baby girl (aged 2) will feed in the morning, pre nap and before bed at night, then anywhere from 2-10 times a night. He felt confident that as baby was feeding for comfort rather than nutrition if I needed Clomid it would be ok.
UKDILAS have said:
We have looked at the properties of Clomid in order to make a risk assessment as there is no information on the use of Clomid during breastfeeding.
- Clomid half life is 5-7 days and the drug may be present in mother’s system up to 35 days after it has been stopped. This increases the likelihood of Clomid passing into breast milk especially with repeated consecutive cycles as it is small enough to be expected to pass into breast milk however pharmacokinetic properties suggest that any passage would be minimal. Therefore it is reasonable to conclude that although Clomid will pass into breast milk it will be in small quantities.
- Despite there being no evidence to confirm safety, there is also no evidence of harm or any adverse effects after exposure via the breast milk. Anecdotally, Clomid has been used in the breastfeeding population for many years, without any untoward effects being reported. Even at normal therapeutic doses, Clomid rarely causes side-effects in the women who take it. We do not know whether there are any longer term effects on infant exposure to this, but to date there has been nothing to suggest that there would be.
- Our recommendation is not age specific to the infant or dependant on the amount or frequency of feeding. Although these factors may influence how much of the drug the infant is exposed to, and how they handle it, these differences are not considered significant enough to alter the advice.
- The normal course length for Clomid is 5 days and shortening this would not limit exposure of the drug due to the long half-life. It may also not be a clinically suitable option to reduce the strength or course. Waiting 6 hours after the dose would also not make a significant difference either, again due to the long half-life of the drug. We would therefore advise that breastfeeding continues as normal.
- Clomid is not usually recommended during the first weeks postpartum due the risk of decreased milk production but this is unlikely to be relevant in a mother with established breastfeeding.
- Overall, there is no information available for the use of Clomid during breastfeeding. However, there is also no information available to suggest drug exposure as a result of breastfeeding causes harm to infants, and based on the properties of the drug, the amount in breast milk is likely to be minimal. Therefore, breastfeeding can proceed with caution in women who are taking Clomid with close monitoring of the infant for side effects such as gastro-intestinal disturbances, flushing and poor feeding.
In Conclusion:
What we know is that clomid assists ovulation by stimulating the release of pituitary gonadotropins, FSH and LSH. We do not know how much it passes into milk as this has not been studied.
It is worth considering that with any medication that does transfer to milk in small doses, with an older infant, a mum who’s milk supply is far lower, will not be likely to be transferring a high dose - particularly when considering the likelihood of further supply reduction from this type of medication:
https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/11291-clomid-while-breastfeeding
It is also worth remembering that original discussion on this subject stated that levels were highest after around 6 hours, so you may want to consider timing your feeds/doses:
https://www.breastfeedingbasics.com/qa/can-clomid-help-get-pregnant-im-nursing
However troublesome the change in stance is, we must acknowledge that Hale as one of the leading specialists does not seem to think this should be taken. It should be noted however that he appears to place very little value on breastfeeding over the age of 18 months - much less than the other leading medication in lactation specialists. This may contribute to his advice.
In the meantime, we would suggest that you read this post and links thoroughly, ensuring you review the information provided at source before making a decision about your treatment. Dependant on your location, you may wish to consider contacting one of the sources above (Wendy Jones, UKDILAS, Rodney Whyte or E-lactancia) to discuss your own circumstances.
Please remember that this is only one specialist, it is well worth considering the full range of information without coming to a panicked decision. Many members over the last four years have said their fertility specialist / consultant has said clomid is safe to take, and many, many members have taken it over the past four years that the group has been running with no known ill effect.
If anyone is in the US and having done their reading decides that they are happy to go ahead and take it, and would like to help out with further research to benefit other mums, it is worth contacting Hales Clinical Research Center on 806-414-9742, as he has indicated that he would be willing to study milk samples.
As a final reminder, for anyone who is worried about the information from Hale and does wish to consider weaning or temporarily stopping please seek support from a breastfeeding professional before doing so.