Positive ferning refers to the crystallization pattern seen under a microscope when a woman’s saliva is dried on a slide during ovulation. When a woman ovulates, her estrogen level peaks, which causes ferning or crystallization of the saliva. A positive ferning pattern shows the woman is currently fertile and able to get pregnant.
When does positive ferning occur?
Positive ferning occurs just before and during ovulation, which is when an egg is released from the ovary. This usually happens about 14 days before a woman’s next period. Ovulation causes a woman’s estrogen level to surge, which in turn causes electrolytes in the saliva to crystallize in a fern-like pattern when the saliva dries on a microscope slide. This crystallization is called “ferning.”
A positive ferning pattern indicates the woman has reached her peak fertility for the menstrual cycle. It means ovulation is occurring or is about to occur within the next 24-48 hours. The egg only lives for about 24 hours after ovulation. So when positive ferning is seen, it means the woman is in her fertile window and has the best chance of getting pregnant if sexual intercourse occurs.
How is a ferning test performed?
A ferning test is very simple and non-invasive. To perform the test:
- The woman collects a sample of saliva on her tongue or from under her tongue.
- She spreads the saliva thinly and evenly on a microscope slide.
- She allows the saliva to completely dry, which takes about 5 minutes.
- The dried saliva slide is then examined under a microscope, usually at 100x magnification.
The saliva will display one of three ferning patterns:
- Positive ferning – a full ferning pattern that has numerous distinct crystallization branches.
- Partial ferning – some crystalline branches are visible but the pattern is not complete.
- Negative ferning – there is no crystallization visible.
What causes the ferning pattern?
The ferning pattern is caused by changes in the composition of the saliva in response to hormonal fluctuations during the menstrual cycle. Here is what happens:
- Estrogen levels increase significantly around ovulation.
- The high estrogen increases the amount of salt (sodium chloride) in the saliva.
- The salt causes the saliva proteins and carbohydrates to crystallize as the saliva dries.
- This crystallization forms a unique ferning or fern-like pattern under the microscope.
When estrogen levels are low during other parts of the cycle, the saliva contains less salt and does not crystallize in the same pattern when it dries. This results in a negative ferning pattern.
What does a positive ferning pattern look like?
Here is what a typical positive ferning pattern looks like under the microscope:
- Thick ferning branches that have finger-like projections coming off them.
- Delicate ferning leaves that join together to form latticework.
- Ferns that are wide at the end and taper as they meet the main branch.
- A symmetrical, geometric appearance.
- Distinct areas of crystallization separated by clear spaces.
The size and intricacy of the ferning indicates peak fertility. Partial ferning may show a few branches and crystallization but the pattern is not full and complete like a positive result.
What affects ferning test results?
Certain factors can affect the accuracy of ferning test results. These include:
- Time of day – Ferning is best observed using saliva collected before eating, drinking, brushing teeth, smoking, or kissing. Morning saliva is optimal.
- Food and beverages – Caffeine, alcohol, high sugar or salt intake can alter ferning patterns.
- Contaminants – Oral hygiene products, lip balm, cigarettes, and blood can distort the saliva sample.
- Hormonal problems – Conditions like polycystic ovarian syndrome (PCOS) can affect natural hormonal fluctuations.
- Medications – Hormonal therapies and fertility medications containing estrogen can increase ferning.
To get the most accurate result, the ferning test should be done first thing in the morning before any food, drink, or oral hygiene. Following the testing guidelines carefully is important.
How accurate are ferning tests?
When performed correctly under optimal conditions, ferning tests can be quite accurate at predicting ovulation. Some key points about accuracy include:
- Ferning tests correctly predict ovulation about 80% of the time in women with regular cycles.
- They are more accurate than other natural fertility indicators like cervical mucus and basal body temperature.
- Accuracy is higher when ferning is monitored for several months to establish a woman’s natural pattern.
- False negatives are more common than false positives.
While no natural fertility test is 100% accurate, ferning testing done properly can detect ovulation with fairly good reliability for many women.
How often should ferning be checked?
To use ferning to predict ovulation and fertility, it is important to check for ferning patterns consistently:
- Testing should begin several days before anticipated ovulation.
- Test 1-2 times per day, preferably at the same times each day.
- Ideally, test daily for several months to identify your personal ferning pattern.
Testing more frequently as ovulation approaches can help detect the ferning surge that precedes ovulation by about 1-2 days. Tracking ferning patterns daily for a few cycles allows you to learn when your peak fertility typically occurs.
What are the limitations of ferning tests?
While ferning tests can be useful for natural fertility tracking, there are some limitations to be aware of:
- Results can be affected by factors like diet, medications, and health conditions.
- Accuracy may decrease in women with irregular cycles.
- Can’t confirm ovulation occurred, only predict it.
- Doesn’t help with timing intercourse after ovulation.
- Does not detect issues affecting fertility or each partner’s fertility capability.
Ferning testing is best used along with other fertility awareness methods like cervical mucus monitoring. It may not work well alone for women with very irregular cycles.
How is ferning different from cervical mucus monitoring?
Ferning and cervical mucus changes are both ways to detect ovulation naturally. Here are the main differences:
| Ferning | Cervical Mucus |
|---|---|
| Uses crystallization of saliva when estrogen surges | Observes changes in mucus as estrogen rises |
| Performed by drying saliva on a slide | Checks sensation and appearance of mucus |
| Viewed under a microscope for fern pattern | Can be observed without tools |
| Results not affected after collection | Mucus can be altered after collection |
| More technically challenging | Easier to learn |
Many women find it helpful to monitor both ferning and cervical mucus around ovulation to confirm hormone changes. However, ferning alone can be used successfully by many women.
Should ferning be used with other fertility awareness methods?
Experts often recommend combining ferning with other natural fertility tracking methods. Here are some benefits of pairing ferning with additional indicators like cervical mucus and basal body temperature:
- More confidence predicting ovulation window
- Ability to confirm ovulation after the fact
- Identify hormonal fluctuations or irregularities
- Reduce chances of inaccurate results
- May improve effectiveness for avoiding pregnancy
Using ferning tests along with other fertility awareness techniques provides a more complete hormonal profile and thorough accuracy checks. However, ferning alone can be effective when done properly.
Can ferning help get pregnant?
Ferning testing can be useful for couples trying to get pregnant naturally. Tracking ferning can help identify the most fertile days each cycle. Key points about using ferning to aid conception include:
- Positive ferning predicts ovulation is approaching.
- Having sex on positive ferning days maximizes chances of pregnancy.
- Helps time intercourse around estimated ovulation.
- Best used along with basal body temperature to confirm ovulation.
- Not as reliable for irregular cycles.
When trying to conceive, having intercourse on days when ferning is positive can optimize the likelihood of sperm meeting the egg. Combining with basal temperature helps confirm ovulation occurred after positive ferning.
Can ferning prevent pregnancy?
Ferning testing can theoretically help couples avoid pregnancy by abstaining or using protection on positive ferning days when conception is most likely. However, there are some major caveats:
- Less effective than other fertility awareness based methods for contraception.
- Does not confirm ovulation already happened.
- No protection from STIs like condoms provide.
- Typically has a higher failure rate than other birth control options.
While some couples use ferning to help prevent pregnancy, it is generally not recommended as an effective contraceptive method by itself. Other fertility awareness techniques like sympto-thermal method are much more reliable if avoiding pregnancy.
Conclusion
In summary, positive ferning is a microscopic crystallization pattern in saliva indicating a woman is ovulating. It occurs due to estrogen-driven changes in the electrolyte composition of saliva around the fertile window. While not perfectly accurate, if performed properly ferning can help predict ovulation fairly reliably. Ferning testing can assist couples looking to achieve or avoid pregnancy when used along with other fertility awareness techniques. As an easy, non-invasive indicator of hormonal status, ferning provides valuable ovulation insights for many women.