How fast does evening primrose oil work to induce labor

With this series (Evening Primrose Oil – EPO), Gina and I both believe that a “natural” induction, is still an induction in a way. You are still using interventions to start labor before you may be ready. 

There are risks and benefits to everything we do in life, and for one person it may be worth taking the risk for the benefit while another person it’s not worth it. 

We always recommend discussing options with your provider and doing your own research before using any of the induction methods we discuss in this series. 

Read our Week 1 Blog: Castor Oil here

Evening Primrose Oil - EPO: What is it?

Evening Primrose Oil is from the Evening primrose flower, this flower blooms at night which is how it got its name. 

The oil that they extract from the seeds of this flower have been used for cervical ripening for a few decades. The Oil contains a high amount of gamma-linolenic acid (GLA), which is a precursor of prostaglandin derivatives. Prostaglandin is needed for cervical ripening!

EPO is used medically for hemorrhoids, dermatological reasons like bruises, eczema, or acne; GI problems; sore throats; and PMS symptoms. It can be applied topically or taken orally. 

It is stated that EPO is a blood thinner and could decrease blood pressure, so if taking blood thinning or blood pressure medication speak with your provider before taking. 

Will it induce labor based on research?

The evidence on if labor is induced with EPO is lacking. The few studies that have been done on EPO are fairly small, so it is not strong evidence. This doesn’t mean it doesn’t work, just that is not proven by evidence. 

The research we have differs based on if EPO was placed vaginally or taken orally, so let’s break that down further.

Vaginal EPO

Studies showed that compared to not using EPO, Vaginal EPO does increase the Bishop Score (likelihood of successful induction) and early labor is shorter. This makes sense in my mind because a lot of early labor is cervical effacement and a little of dilation. If the evening primrose oil helps soften and efface the cervix, it makes sense that early labor does not need to be as long.  

• In one study the cervix was both dilated and effaced more compared to the control groups. Their early labors were shorter, decreased likelihood of c-section, and less need for oxytocin. Had no effect on their active labor or pushing time. 
• In another study they used it during medical induction along with IV oxytocin. They found that the length of early labor was also shortened but no affect on active labor and pushing time. 

Oral EPO

Most studies that researched oral EPO only do not seem to support the use of oral EPO for cervical ripening. Most of them showed little to no different in the Bishop score between the usages, but there were limitations to those studies. I could only find one that supported that oral could cause cervical ripening, but the dosage requirement was 1 capsule 3 times a day over a week compared to other studies of 1-2 times a day. There was a significant change in the Bishop score in the EPO group, without any increased risk for the baby. There was a decreased risk of a c-section in the EPO group versus the control group!

Vaginal vs Oral EPO

One study done recently did a study on comparing Vaginal EPO, Oral EPO, or nothing. This is the only study I could find that did this. Their results showed the Vaginal EPO is a little more effective compared to Oral EPO, but both of them were more effective than doing nothing. The bishop score increased and pushing stage was shorter in the Vaginal EPO. The oral EPO only had an increased Bishop score only. The EPO groups had a higher likelihood of having a vaginal birth, but it was not a significant amount. The vaginal EPO had a lower rate of inductions, but it was not statistically significant.

Most of the studies did not find any complications associated with EPO use, the only side effects people complained of were slight headaches and slight GI upset. One study found that it may be associated with Prolonged Rupture of Membranes, Increased instrument delivery, and need for oxytocin administration, but no other studies found a correlation. 

In Summary, EPO may be a way to ripen and soften the cervix for labor with very little side effects and no increased risk for baby. Vaginally administration seems to work better than oral!

How does it work?

The GLA (gamma-linolenic acid) is a precursor to prostaglandins. Prostaglandins are what play a huge part in the cervical ripening of the cervix and part of the positive feedback loop of labor. 

It is thought that by increasing the prostaglandins this will cause the cervix to ripen and soften to be easier to dilate. The prostaglandins will also tell the brain to start producing more oxytocin to then stimulate contractions. 

How do I take it?

Recommendation varies but the most common ways were:

Vaginally

• 1000mg capsules once a day, placed as close to the cervix as possible. Some recommend putting holes in the capsules to ensure the oil touches the cervix, other don’t because the capsule will dissolve in the vagina.
  

Orally

• 1000mg capsules 1-3 times a day. 

Risks & Benefits

Benefits

• Increased Bishop Score
• Decrease Risk for C-section
• Shorter early labor stage
• *If taken vaginally shorter pushing stage*

Risks

• Headache
• GI Upset
• When used vaginally – feeling of wetness/oily feeling as the primrose oil leaks out
• *Prolonged Rupture of Membranes*
• *Instrument Assisted Delivery*
• *Some say Prelabor Rupture of Membranes is a risk, but this is not supported by an evidence I could find*
  • It causes thinning of the cervix, so thought is that if it causes the cervix to thin out, it could also cause the amniotic sac to thin and become weaker to break prior to labor starting
• Can cause increase in bleeding if on other blood thinners
• Can cause decrease in blood pressure if on blood pressure medication
• No studies with someone who had a prior c-sections
  • It is a cervical ripener so in theory it could cause thinning of the c-section scar and increase risk of uterine rupture similarly to other cervical ripening agents.

Our Professional Opinion

Roxanne: Labor & Delivery Nurse

I have not seen a crazy amount of people admitted to LND after taking primrose oil EPO. So I do not think it causes spontaneous labor to occur, but I have seen the difference of people who used it and having softer cervixes! If you know you will be needing to be induced potentially this could help make the induction process easier. If the cervix is not ripened that’s an additional step we have to do during the induction process. 

Seems the longer you use it for it the better the results, maybe starting earlier around 38 weeks might lead to better results. Especially if you know you will have to be induced. 

Mamastefit Survey Results

The Results of our Mini Survey we did on 9/7/2022 on Instagram. We asked out followers about Evening Primrose oil and their experience. 

Did you take Evening Primrose Oil? We had 746 people answer

• 21% said Yes
• 79% said No

When Asked why No? the most common answers were:

• Did not know it was an option
• Did not think it was necessary/did not think it would work
• PROM (Pre-labor Rupture of Membranes)
• VBAC
• Seemed messy (when used vaginally)

When asked why yes? The most answers were

• Read it on the internet/podcasts as a good option
• Provider recommended
• Heard positive stories of it working
• Previous success
• Wanting to avoid induction

How many weeks were you when you started using it? We had 219 people respond

• 37 weeks: 41%
• 38 weeks: 23%
• 39 weeks: 16%
• 40+ weeks: 19%

Did you experience PROM? We had 217 people respond

• Yes: 31%
• No: 69%

Spontaneous Labor or Induction after taking EPO? We had 336 people respond

• Spontaneous labor: 66%
• Induction: 34%

How long was labor if EPO was used? We had 179 people respond

• <12 hours: 38%
• 12-24 hours: 30%
• 24-48 hours: 23%
• >48 hours: 8%

How much did you use and how often? Most Common answers were:

• 1-2 capsules placed vaginally once a day, most common time of day at night
• 1-2 capsules by mouth once a day
• Some did both orally and vaginally
• Some had a protocol of doing 1 pill then increasing to 2 pills for both oral and vaginal dosages

If induced: How was the induction? We had 87 people respond

• Quick and easy 43%
• LONG 57%

Any Heavy Bleeding during delivery if used EPO? We had 144 respond

• Yes: 23%
• No: 77%

Any GI Distress? We had 163 people respond

• Yes: 19%
• No: 81% 

Favorite Brands of EPO:

• Target
•  

How Long Does evening primrose oil take to kick in?

How much evening primrose oil should I insert to induce labor?

Can inserting evening primrose oil cause contractions?

How many evening primrose capsules should I take a day to induce labor?