“Should I be taking progesterone this time?”
It is a very understandable question after a miscarriage.
When you have been through the heartbreak of losing a pregnancy, finding out you are pregnant again can bring a mixture of emotions that are difficult to put into words.
There can be excitement, but also fear.
You may find yourself analysing every symptom, worrying about every twinge and wondering whether there is anything — anything at all — that you can do differently this time.
That is where progesterone often comes into the conversation.
You may have read that progesterone can help prevent miscarriage. You may have been offered it before. Or perhaps you have been told by someone else that you “should” be taking it from the moment you get a positive pregnancy test.
But the evidence is a little more nuanced than that.
Progesterone can be helpful in some circumstances, but it isn’t recommended for everyone who has experienced a miscarriage.
So let’s talk about what progesterone actually does, what the research tells us and where it may have a role.
What does progesterone do in early pregnancy?
Progesterone is one of the hormones that plays an important role in supporting an early pregnancy.
After ovulation, progesterone helps prepare and maintain the lining of the womb so that an embryo can implant and continue to develop.
In early pregnancy, progesterone continues to support the pregnancy while the placenta develops. Later in the first trimester, the placenta becomes the main source of progesterone.
So it is an important hormone.
But that doesn’t mean that every miscarriage happens because there isn’t enough progesterone.
And this distinction is really important.
Although progesterone is important in supporting early pregnancy, miscarriage is not usually as simple as having “too little progesterone”.
Many early miscarriages occur because the pregnancy itself has a chromosomal abnormality that means it cannot continue developing normally.
Taking progesterone cannot correct that.
This is one reason why progesterone isn’t simply prescribed to everyone who has experienced a previous miscarriage.
So why might progesterone help some women?
This is where the evidence becomes particularly interesting.
Research has looked at women who experience vaginal bleeding in early pregnancy — particularly before 12 weeks — and who have also had a previous miscarriage.
The theory is that progesterone may provide additional support to the pregnancy at a time when the pregnancy is vulnerable.
The large PRISM trial looked at women with early pregnancy bleeding and investigated whether vaginal micronised progesterone could improve the chance of having a live baby.
Overall, the difference between progesterone and placebo was relatively small.
But when researchers looked more closely at women who had previously miscarried, there appeared to be a benefit.
And the benefit became more apparent as the number of previous miscarriages increased.
This is why the current UK guidance is much more specific than simply saying “progesterone prevents miscarriage”.
What does the evidence actually show?
There are three groups worth separating.
1. Previous miscarriage AND bleeding in the current pregnancy
This is the group where the evidence is strongest.
If you have had at least one previous miscarriage and then develop vaginal bleeding in an early pregnancy, vaginal micronised progesterone may increase the chance of the pregnancy resulting in a live birth.
This is the situation in which NICE recommends offering progesterone.
Tommy’s summarises the evidence as suggesting that, among women who are bleeding in early pregnancy, progesterone may increase the chance of a successful pregnancy by around 5% for those who have had one or two previous miscarriages, and by around 15% for those who have had three or more previous miscarriages. These are estimates of the additional benefit seen in the research rather than a guarantee for an individual pregnancy.
2. Bleeding in early pregnancy, but no previous miscarriage
This is different.
The evidence has not shown the same clear benefit from progesterone for women who have bleeding in early pregnancy but have never previously miscarried.
That doesn’t mean the bleeding should be ignored — it absolutely needs appropriate assessment — but progesterone isn’t routinely recommended simply because bleeding has occurred.
3. Previous miscarriage, but no bleeding in the current pregnancy
This is another important distinction.
You might reasonably think:
“I’ve had a miscarriage before, so surely taking progesterone from the moment I get pregnant again would reduce my risk?”
It sounds logical.
Unfortunately, the evidence doesn’t currently support routine progesterone treatment simply because you have had a previous miscarriage.
The PROMISE trial looked at progesterone in women with previous unexplained miscarriages and did not demonstrate a significant improvement in live birth rates when progesterone was given routinely in the next pregnancy.
So at the moment, a previous miscarriage alone isn’t an indication for progesterone.
What does NICE recommend?
This is where the UK guidance is particularly helpful.
NICE recommends offering vaginal micronised progesterone 400 mg twice daily to women who have:
- vaginal bleeding in early pregnancy
- a history of at least one previous miscarriage
- and an ultrasound confirming that the pregnancy is in the womb.
If a fetal heartbeat is confirmed, NICE recommends continuing progesterone until 16 completed weeks of pregnancy.
One important point is sometimes missed here.
You do not necessarily have to wait until a heartbeat can be seen before progesterone can be started.
If it is very early in the pregnancy, an ultrasound may confirm that the pregnancy is in the womb while it is still too early to see a heartbeat. Current guidance allows progesterone to be started in this situation if the other criteria are met.
There is an important reason for establishing the location of the pregnancy.
Progesterone is not a treatment for an ectopic pregnancy, and bleeding in early pregnancy can have several causes. An ultrasound assessment is therefore an important part of deciding what is happening and what treatment, if any, is appropriate.
What if I’ve had more than one miscarriage?
This is an area where conversations can become particularly difficult.
If you have experienced recurrent miscarriage, it is completely understandable to want to try anything that might improve your chances next time.
The evidence suggests that progesterone is particularly helpful when recurrent miscarriage is accompanied by bleeding in an early pregnancy.
However, progesterone hasn’t been shown to reliably prevent recurrent miscarriage when there is no bleeding in the current pregnancy.
That can feel frustrating when what you really want is something proactive that you can do.
But sometimes good medical care involves being honest about where the evidence stops.
Does progesterone guarantee that the pregnancy will continue?
No.
And this is important to understand before starting treatment.
Progesterone may increase the chance of a live birth in the particular group of women where the evidence supports its use, but it cannot prevent every miscarriage.
Some pregnancies will unfortunately miscarry despite progesterone because the underlying reason for the miscarriage is unrelated to progesterone.
It is also important not to interpret a miscarriage as meaning that you “didn’t have enough progesterone” or that you should have taken it sooner.
Pregnancy loss is rarely that simple.
Is progesterone safe?
The research so far has not identified evidence of harm to the mother or baby from progesterone when used for this purpose.
NICE considers the potential benefits and risks when making its recommendations. Tommy’s also explains that, while current evidence is reassuring, there is not enough evidence to completely rule out very rare events or every possible long-term outcome.
As with any treatment in pregnancy, it is sensible to have a conversation with your healthcare professional about your individual circumstances.
Why is an early pregnancy scan important?
If you have previously experienced miscarriage, another pregnancy can feel very different from the first.
You may want to know as soon as possible that the pregnancy is in the womb and developing as expected.
An ultrasound scan can help establish the location of the pregnancy and, depending on how far along you are, whether a fetal pole and heartbeat can be seen.
It can also help guide decisions about progesterone if you are experiencing bleeding.
And sometimes it is simply too early to see everything clearly.
That doesn’t necessarily mean something is wrong. Early pregnancy changes very quickly, which is why a repeat scan may sometimes be recommended if the first scan is inconclusive.
But I think there is another side to this that is sometimes overlooked.
After miscarriage, reassurance matters too.
A scan cannot guarantee that a pregnancy will continue, but for some women it can provide an important point of reassurance and help make sense of what is happening.
What if I feel I need a little more reassurance this time?
This is where individualised care matters.
You may have had one previous miscarriage, or several.
You may have had bleeding in a previous pregnancy.
You may have used progesterone successfully during fertility treatment.
Or perhaps you have been given progesterone in a previous pregnancy and are wondering whether the same approach should be used again.
These circumstances aren’t necessarily interchangeable.
The right question isn’t simply:
“Does progesterone work?”
It is:
“Does the evidence suggest progesterone is likely to help someone in my particular situation?”
That is a much more useful conversation.
And what about progesterone after a miscarriage itself?
It is worth making another distinction here.
Progesterone is not a treatment for a miscarriage that has already occurred.
Once a pregnancy has unfortunately ended, progesterone cannot reverse the miscarriage.
The role we are talking about is supporting a subsequent pregnancy in particular circumstances — especially when there is bleeding in early pregnancy and a previous miscarriage.
That distinction can easily become blurred online.
The emotional side matters too
There is something else I think is important to say.
After a miscarriage, it is very easy to feel that you should have done something differently.
A miscarriage is not usually something you caused, and taking progesterone is not a guarantee that a pregnancy will continue.
When you become pregnant again, it is entirely understandable to want more monitoring, more information and more reassurance.
That doesn’t make you anxious or difficult.
It means you’ve been through something difficult.
So, could progesterone be right for you?
The answer depends on your circumstances.
The strongest UK evidence is for women who have had a previous miscarriage and develop vaginal bleeding in a subsequent early pregnancy, particularly before 12 weeks, once an intrauterine pregnancy has been confirmed by ultrasound.
For women who have had a previous miscarriage but have no bleeding, routine progesterone is not currently supported by the evidence.
And for women experiencing bleeding who have never previously miscarried, progesterone has not been shown to provide the same benefit.
That doesn’t mean there is nothing that can be done.
It means the focus should be on assessing the pregnancy properly, understanding your individual history and deciding what is appropriate for you.
At West Wales Women’s Wellbeing, we offer early pregnancy ultrasound scans and can talk through what is happening in your pregnancy, including whether progesterone may be appropriate in light of your previous pregnancy history and current symptoms.
The aim isn’t to prescribe progesterone simply because you’ve had a miscarriage.
It is to help you understand whether there is good evidence that it could benefit you.
The bottom line
Progesterone is an important hormone in early pregnancy, but the evidence for giving additional progesterone is quite specific.
It isn’t a universal treatment after miscarriage.
For women with a previous miscarriage who experience bleeding in an early pregnancy, there is good evidence that vaginal micronised progesterone can increase the chance of a live birth, and this is reflected in current NICE guidance.
For women with a previous miscarriage but no bleeding, the evidence does not currently support routine progesterone treatment.
And perhaps most importantly, having a miscarriage does not mean that your next pregnancy is destined to end in the same way.
Sometimes what women need most is not simply another medication.
It is careful assessment, honest information, appropriate monitoring and someone who understands why the next pregnancy can feel so frightening.
You don’t have to navigate that uncertainty alone.
Further support after miscarriage
If you’ve experienced miscarriage and would like further information or support, Tommy’s has a wealth of evidence-based information about miscarriage, pregnancy after miscarriage and progesterone in early pregnancy.
They also have a specialist midwife team who can offer support and answer questions about pregnancy loss.
You can find their information and support through Tommy’s website.