Cervical mucus: reading the cycle stages, egg white mucus, and ovulation

Cervical mucus is the fertility sign you can observe every day without any device and at no cost. It changes so clearly over the cycle that you can often recognize your fertile days by it a few days before ovulation (ASRM 2022).

This is more than forum wisdom. In a European study of 782 women and 7,288 cycles, the quality of the mucus on the day of sex predicted the chance of pregnancy better than the timing relative to ovulation (Bigelow 2004).

Data box: What mucus on the day of sex reveals about the chance of pregnancy

Among 193 Italian women who observed their mucus using the Billings method, the chance of conception was 0.3% on days without noticeable mucus and 29% on days with the most fertile type of mucus (Scarpa 2006). In a US study, it was highest on the peak day of the mucus: 38% in 309 normally fertile couples and 14% in 117 couples with reduced fertility (Stanford 2003).

What is cervical mucus?

Cervical mucus is produced in the cervix, the neck of the uterus. On most days of the cycle, it blocks the entrance to the uterus. Shortly before ovulation it becomes fluid, and afterward it thickens again (familienplanung.de 2026). In the fluid phase, sperm can pass through and wait for ovulation for up to 5 days in the cervix and uterus (familienplanung.de 2026).

Two hormones control this change:

• Estrogen rises while the follicles mature. The mucus becomes more abundant, clearer, wetter, and stretchier. This alkaline mucus lets sperm through best (FSRH 2015).
• Progesterone is produced by the corpus luteum after ovulation. The amount of mucus drops abruptly (Najmabadi 2021), and the mucus becomes thick and sticky, blocks the way for sperm, and slows their movement (FSRH 2015).

How the hormones work together over the whole cycle is explained in the guide Menstrual cycle.

Not everything you notice at the vaginal opening is cervical mucus. Semen, lubricant, or a vaginal infection can mask or change it (WHO 2022, FSRH 2015). More on this under What interferes with observation.

Cervical mucus throughout the cycle: the stages chart

How many days each stage lasts depends on your cycle length (FSRH 2015).

1. Dry

   after your period

   Sensation

   dry

   Appearance

   no visible mucus

   Fertility

   low

2. Creamy

   a few days before ovulation

   Sensation

   moist or sticky

   Appearance

   white or creamy, cloudy, not stretchy

   Fertility

   rising

3. Stretchy

   around ovulation

   Sensation

   wet, slippery, slick

   Appearance

   clear and glassy like raw egg white, stretches up to a finger’s length

   Fertility

   highest

4. After ovulation

   until your next period

   Sensation

   sticky or dry

   Appearance

   thick, sticky, cloudy, or no mucus at all

   Fertility

   drops quickly

In detail, from the first day of the cycle, in a cycle with ovulation:

Not every woman sees every stage, and the order of the two most fertile qualities is not fixed. In some women, the mucus at the peak is more watery than stretchy. Studies count clear or partly clear mucus, stretchy mucus, and a smooth, slippery sensation equally as mucus of the highest quality (Najmabadi 2021, Ecochard 2015). The sensation is therefore at least as meaningful as the appearance.

How many days are normal? In 2,488 cycles of 528 women aged 18 to 40 without known fertility problems, there were on average 6.4 days per cycle with mucus of the highest quality, and 4 to 8 days in half of the cycles. In 72% of the women, this number varied by more than 3 days between their cycles (Najmabadi 2021).

Cervical mucus before ovulation

Mucus announces ovulation in advance. In an early study of 24 women, it began on average 5.9 days before the ovulation estimated from hormone levels (Hilgers 1978). The US professional society ASRM describes how the amount of mucus increases with estrogen over the 5 to 6 days before ovulation and is greatest 2 to 3 days before (ASRM 2022).

If you are trying to conceive, this means: do not wait for the perfect, stringy mucus. The FSRH counts the peak day and the 2 days before it as the most fertile time, but a pregnancy is possible on any day of the fertile window (FSRH 2015). In normally fertile couples, the chance per day was already above 5% 3 days before the peak day (Stanford 2003).

The calendar gives only a rough idea of when your fertile mucus will appear. In the Italian study, even on the most common day, cycle day 13, only 59% of cycles had mucus of the most fertile type. Outside cycle days 10 to 17, it was less than 20% (Scarpa 2006). The Ovulation Calculator shows you from when observing is especially worthwhile in your cycle.

Cervical mucus during ovulation: the peak day

The peak day is the last day with the mucus that is best for you, for example glassy and stretchy (AWMF 015-095). So it does not mean the day with the most mucus, but the last day with wet, smooth, clear mucus. You can recognize it only in hindsight: the day after, the mucus is thicker or gone completely (FSRH 2015, WHO 2022).

Several studies have examined how close the peak day is to ovulation:

The authors of the ultrasound study therefore consider the mucus peak a possibly better indicator of ovulation than the LH peak (Ecochard 2001). But it is not accurate to the day. Expect that ovulation may be one to two days before or after your peak day (Hilgers 1978). And because you recognize the peak day only the following day, the wet, smooth days before it are what count for planning.

Cervical mucus after ovulation

After ovulation, the corpus luteum produces progesterone, and the mucus becomes thick and sticky again or disappears (FSRH 2015). At the vaginal opening, it then feels sticky or dry. The mucus now acts as a barrier and holds sperm back (FSRH 2015).

The chance of pregnancy drops quickly after the peak day. In normally fertile couples, it was still above 5% up to 2 days after the peak day, in couples with reduced fertility only up to 1 day after (Stanford 2003). The rules for contraception build in a buffer: according to the FSRH and the WHO, the 3 full days after the peak day are still fertile, and from the fourth day on, the time is considered infertile (FSRH 2015, WHO 2022).

Basal body temperature, which progesterone raises only after ovulation, gives you a look back (FSRH 2015). However, the temperature chart is not reliable proof of ovulation either (NICE NG257, recommendation 1.18.9). How to measure and read the chart is covered in the guide Measuring basal body temperature. How long it takes from ovulation to the next period is shown in the Period Calculator.

Stretch test: how to observe your mucus

All you need is a little attention throughout the day. Here is how:

1. Check every time you go to the toilet. In the large studies, the women observed their mucus at the vaginal opening during their normal trips to the toilet, not inside (Najmabadi 2021). The WHO mentions fingers, underwear, toilet paper, or the sensation at the vaginal opening (WHO 2022).
2. Pay attention to the sensation first. Dry, moist, wet, or smooth and slippery? A smooth, slippery sensation counts as mucus of the highest quality, even if you can hardly see anything (Najmabadi 2021).
3. Then the appearance. White, creamy, and cloudy, or clear and glassy?
4. Check how stretchy it is. Take a little mucus between your thumb and index finger and slowly pull your fingers apart. Around ovulation, it can be drawn into a thread up to a finger’s length. Before and after, it is firm and sticky (frauenaerzte-im-netz.de 2018).
5. Write it down every day. The women in the studies kept a daily diary (Najmabadi 2021). A template with columns for mucus, temperature, and LH test can be found in the guide Measuring basal body temperature.
6. Keep at it for several cycles. Many women recognize the patterns reliably only after at least three cycles (FSRH 2015).

Outside or inside? The German-language S2k guideline (Germany, Austria, and Switzerland) describes observing on the outside, at the vulva, so you do not need to go into the vagina (AWMF 015-095). The portal frauenaerzte-im-netz.de considers this unreliable and advises taking the mucus directly from the cervix with two fingers (frauenaerzte-im-netz.de 2018). The large studies on the mucus pattern and the chance of conception are based on observation from the outside (Stanford 2003, Najmabadi 2021). So if observing from the outside gives you clear results, it is enough.

What interferes with observation

This rule comes from contraception, so you do not need to have sex less often. On the day after sex, the observation simply tells you less.

Cervical mucus in early pregnancy: what the evidence shows

You cannot tell from your mucus whether you are pregnant. Cleveland Clinic describes how some women notice clumpy mucus, or mucus that stays moist for longer, during pregnancy, but it explicitly advises against predicting a pregnancy from mucus. Only a pregnancy test is certain (Cleveland Clinic 2024).

The reason lies in the hormones. After every ovulation, progesterone makes the mucus thick and sticky (FSRH 2015), whether an egg has been fertilized or not. Until your period is due, the mucus therefore follows the same hormone in cycles with and without a pregnancy. We have not found a study that shows a different mucus pattern in cycles with a pregnancy before the period is due.

The following is established:

• During pregnancy, the mucus forms a large plug in the cervix, which comes away shortly before or during labor. According to a review, it is thought to protect against ascending infections (Becher 2009).
• More discharge in pregnancy is normal and helps prevent infections from traveling up from the vagina into the uterus (NHS 2024). We have not found reliable information in any source on the week from which this begins.
• What a long high phase of the temperature can mean is explained in the section Basal body temperature and pregnancy. When a test becomes reliable is explained in the Period Calculator.

During pregnancy, contact your midwife or gynecologist if the discharge smells unpleasant, is green or yellow, itches or burns, or if urinating hurts. These can be signs of a vaginal infection (NHS 2024).

Little or no stretchy cervical mucus

First, something reassuring: the chance is highest on days with clear, smooth mucus, but such mucus is not a prerequisite for pregnancy (ASRM 2022).

Having only a few days with good mucus is also common. In the large analysis, 12.2% of cycles had at most 2 days with mucus of the highest quality. Women aged 30 or older who had not yet given birth had 5.3 such days on average, younger women without children 6.4. Women with children had 1.3 days more on average than women without. However, women aged 35 or older were barely represented in the study, with only 27 (Najmabadi 2021).

Possible reasons for little fertile mucus:

• No ovulation in this cycle. In the Hilgers study, 64 of 65 cycles with hormonally confirmed ovulation showed a mucus peak, and in 8 of 73 cycles there were signs of absent ovulation or a disturbed second half of the cycle (Hilgers 1978). If there is no peak day over several cycles, it is worth looking at ovulation itself.
• Pill stopped recently: Women who had stopped the pill within the last 12 weeks had markedly poorer mucus scores than women who had not taken the pill in the past year (FSRH 2015).
• Breastfeeding: Normal mucus returns later while breastfeeding (WHO 2022).
• Clomiphene: In a meta-analysis of 6 randomized studies, the risk of unfavorable mucus was more than seven times higher with 100 and 150 mg of clomiphene daily (odds ratio 7.9 and 7.5). At 50 mg, the effect was not significant (Roumen 1997). Additional estrogen improved the mucus in 4 studies (odds ratio 2.87; Roumen 1997). Whether that is an option for you is something your fertility practice will clarify. How the treatment works is explained in the guide Fertility drugs.
• Medications: Antihistamines can change the mucus (WHO 2022).
• Surgery on the cervix or an infection (Cleveland Clinic 2024).

What helps if mucus is lacking

Broaden your timing. If your mucus shows little, add other signs, such as ovulation tests. ASRM recommends sex every 1 to 2 days in the fertile window and considers 2 to 3 times a week almost as effective (ASRM 2022). NICE suggests sex every 2 to 3 days (NICE NG257).

Use a lubricant if you are dry. In a cohort study of 6,467 women, using lubricant during sex was not associated with a lower chance of pregnancy (McInerney 2018). What happens to sperm in the lab and which products do better is covered in the guide Fertility friendly lubricant.

Be realistic about home remedies. For the cough medicine guaifenesin, which circulates in forums as a mucus aid, there is only a two-page short report from 1982 (Check 1982). We have not found a controlled study on it, nor a study showing that drinking a lot improves cervical mucus.

Bypass the mucus. With insemination (IUI), the sperm are placed directly into the uterus at the time of ovulation (NHS 2024), so they do not have to pass through the cervix. Who it is suitable for is covered in the guide IUI treatment.

A Dutch study of 410 couples facing infertility shows that good mucus days matter: the more days on which sperm could penetrate the mucus well, the higher the chance of pregnancy without treatment (Keulers 2007). Even so, NICE does not recommend the postcoital test, in which the mucus is examined after sex, as a routine test because it does not predict the chance of pregnancy (NICE NG257, recommendation 1.18.1).

When to get it checked

• Unusual discharge: An unpleasant smell can point to an infection, and cottage-cheese-like discharge is also considered abnormal (Cleveland Clinic 2024). An infection also interferes with mucus observation (WHO 2022).
• Irregular cycle: If your cycles are repeatedly shorter than 21 or longer than 35 days, or you have fewer than 8 periods a year, infrequent or absent egg maturation is considered present according to the German guideline (AWMF 089-004). A medical evaluation then makes more sense than continuing to observe. More on this in the guide Getting pregnant with PCOS.
• No pregnancy despite regular sex: The German-language guideline (Germany, Austria, and Switzerland) recommends an evaluation after 12 months, after 6 months for women over 35, and immediately at a fertility clinic for women over 40 (AWMF 015-085).

What is examined is covered in the guide Fertility tests for women, and the Infertility guide describes how both partners are evaluated.

Combining cervical mucus, basal body temperature, and ovulation tests

Each sign shows a different moment in the cycle:

Methods that combine temperature and mucus are called symptothermal. The Sensiplan method, which is widely used in Germany, evaluates both signs according to the principle of double-checking, and the cervix can be felt instead of observing mucus (AWMF 015-095). The Billings method uses mucus only and is not widely used in German-speaking countries (AWMF 015-095). The German-language fertility guideline (Germany, Austria, and Switzerland) names ovulation tests and cycle self-observation as ways to supplement or replace medical cycle monitoring or lab tests in the second half of the cycle (AWMF 015-085).

In everyday terms: mucus shows you that the fertile window is opening, an LH test narrows down ovulation, and temperature rises afterward. More on this in the section Combining basal body temperature with cervical mucus and ovulation tests. Fertility trackers and apps in which you record your mucus are compared in the Fertility tracker comparison, and other signs such as mittelschmerz are described in the article Ovulation symptoms.

How well does mucus observation identify the fertile window?

The fertile window covers 6 days: the 5 days before ovulation and the day of ovulation (familienplanung.de 2026). A study of 107 women with daily ultrasound examined how well mucus identifies these days (Ecochard 2015):

• Any mucus captured all fertile days (sensitivity 100%), but produced a fertile window of 11 days, considerably more than the 6 biologically fertile days.
• Mucus of the highest quality, meaning clear, smooth, or stretchy, captured the fertile window with 96% sensitivity and marked fewer unnecessary days. In fewer than 10% of cycles, it appeared before the fertile window.
• This mucus identified ovulation itself, including the day before, with 88% sensitivity.

The studies on the chance per day show the same picture. In the European analysis, the chance rose markedly with mucus quality. When mucus quality was factored out, the chance differed only slightly between the days of the fertile window (Bigelow 2004).

Whether couples actually get pregnant faster by observing their mucus is less clear:

The Evans-Hoeker study only observes. The authors themselves consider it possible that other differences between the women distort the result (Evans-Hoeker 2013).

What does this mean for you? Mucus is a good, free guide to the days with the highest chance. Start having regular sex as soon as the mucus becomes moist, and do not stop at the first stretchy day: up to 2 days after the peak day, the chance per day in normally fertile couples was still above 5% (Stanford 2003). The Ovulation Calculator estimates the fertile days of your next cycle, and its section on chances shows the chance for each day around ovulation. Your mucus will then show you whether the time has actually come.

Frequently asked questions

What does cervical mucus look like during ovulation?

Clear, glassy, and stretchy like raw egg white, often also thin and watery. At the vaginal opening, it feels wet, slippery, or slick (FSRH 2015, WHO 2022). Around ovulation, it can be stretched between two fingers up to a finger’s length (frauenaerzte-im-netz.de 2018). The last day with this quality is the peak day (AWMF 015-095).

How long after stretchy cervical mucus do you ovulate?

Usually around the last day with stretchy mucus. In one study, ovulation was on average 0.31 days before this peak day, and within 2 days before or after it in 95.4% of cycles (Hilgers 1978). You can recognize the peak day only the next day, when the mucus becomes thicker or is gone (FSRH 2015).

What does cervical mucus look like after ovulation?

Thick, sticky, and cloudy, or there is no mucus at all. Progesterone from the corpus luteum causes this change, and the mucus now holds sperm back (FSRH 2015). From the fourth day after the peak day, the fertile time is considered over (FSRH 2015, WHO 2022).

Can I tell from my cervical mucus whether I am pregnant?

No. After every ovulation, progesterone makes the mucus thick and sticky, whether a pregnancy has begun or not (FSRH 2015). Cleveland Clinic advises against predicting a pregnancy from mucus; only a test is certain (Cleveland Clinic 2024).

Can I get pregnant without stretchy cervical mucus?

Yes. The chance is highest on days with clear, smooth mucus, but such mucus is not a prerequisite for pregnancy (ASRM 2022). In a large analysis, 12.2% of cycles had at most 2 days with mucus of the highest quality (Najmabadi 2021). If there is no peak day at all over several cycles, have your cycle checked by a doctor.

How many days of fertile cervical mucus do you have?

In women without known fertility problems, an average of 6.4 days of highest-quality mucus per cycle, and 4 to 8 days in half of the cycles. In women aged 30 or older who had not given birth before, it was 5.3 days on average (Najmabadi 2021). The number often varies by more than 3 days from cycle to cycle.

Sources

Guidelines and professional societies

• FSRH Clinical Guidance: Fertility Awareness Methods, Faculty of Sexual & Reproductive Healthcare (now CoSRH), 2015
• Family Planning: A Global Handbook for Providers, chapter Fertility Awareness Methods and glossary, WHO and Johns Hopkins Bloomberg School of Public Health (CCP), 2022
• S2k guideline Non-hormonal contraception, AWMF 015-095, sections 1.5 to 1.9, DGGG, OEGGG, and SGGG, as of December 2023
• Diagnostics and therapy before medically assisted reproduction treatment, S2k guideline AWMF 015-085, version 2.0, recommendation 3.1.E1, DGGG, OEGGG, and SGGG, as of April 2026
• Patient guideline: diagnosis and treatment of polyendocrine metabolic ovarian syndrome (PMOS, formerly PCOS), AWMF register no. 089-004, AWMF, as of June 2026
• Practice Committee of ASRM and SREI: Optimizing natural fertility, a committee opinion, Fertil Steril 2022;117:53-63, ASRM, 2022
• NICE NG257: Fertility problems, assessment and treatment, chapter Investigation of fertility problems and management strategies, recommendation 1.18.1, NICE, 2026
• NICE NG257: chapter Initial advice to people concerned about delays in conception, NICE, 2026
• Gibbons T, Reavey J, Georgiou EX, Becker CM: Timed intercourse for couples trying to conceive, Cochrane Database Syst Rev 2023, CD011345.pub3

Studies on mucus, peak day, and ovulation

• Hilgers TW, Abraham GE, Cavanagh D: Natural family planning I. The peak symptom and estimated time of ovulation, Obstet Gynecol 1978;52(5):575-582
• Ecochard R, Boehringer H, Rabilloud M, Marret H: Chronological aspects of ultrasonic, hormonal, and other indirect indices of ovulation, BJOG 2001;108(8):822-829, doi:10.1111/j.1471-0528.2001.00194.x
• Ecochard R, Duterque O, Leiva R, Bouchard T, Vigil P: Self-identification of the clinical fertile window and the ovulation period, Fertil Steril 2015;103(5):1319-1325, doi:10.1016/j.fertnstert.2015.01.031
• Stanford JB, Smith KR, Dunson DB: Vulvar mucus observations and the probability of pregnancy, Obstet Gynecol 2003;101(6):1285-1293, doi:10.1016/s0029-7844(03)00358-2
• Bigelow JL, Dunson DB, Stanford JB, Ecochard R, Gnoth C, Colombo B: Mucus observations in the fertile window, a better predictor of conception than timing of intercourse, Hum Reprod 2004;19(4):889-892, doi:10.1093/humrep/deh173
• Scarpa B, Dunson DB, Colombo B: Cervical mucus secretions on the day of intercourse, an accurate marker of highly fertile days, Eur J Obstet Gynecol Reprod Biol 2006;125(1):72-78, doi:10.1016/j.ejogrb.2005.07.024
• Najmabadi S, Schliep KC, Simonsen SE et al.: Cervical mucus patterns and the fertile window in women without known subfertility, a pooled analysis of three cohorts, Hum Reprod 2021;36(7):1784-1795, doi:10.1093/humrep/deab049
• Evans-Hoeker E, Pritchard DA, Long DL, Herring AH, Stanford JB, Steiner AZ: Cervical mucus monitoring prevalence and associated fecundability in women trying to conceive, Fertil Steril 2013;100(4):1033-1038, doi:10.1016/j.fertnstert.2013.06.002
• Keulers MJ, Hamilton CJ, Franx A, Evers JL, Bots RS: The length of the fertile window is associated with the chance of spontaneously conceiving an ongoing pregnancy in subfertile couples, Hum Reprod 2007;22(6):1652-1656, doi:10.1093/humrep/dem051
• Becher N, Adams Waldorf K, Hein M, Uldbjerg N: The cervical mucus plug, structured review of the literature, Acta Obstet Gynecol Scand 2009;88(5):502-513, doi:10.1080/00016340902852898

Studies on medications and lubricants

• Roumen FJ: Decreased quality of cervical mucus under clomiphene, a meta-analysis (in Dutch), Ned Tijdschr Geneeskd 1997;141(49):2401-2405
• Maxson WS, Pittaway DE, Herbert CM, Garner CH, Wentz AC: Antiestrogenic effect of clomiphene citrate, correlation with serum estradiol concentrations, Fertil Steril 1984;42(3):356-359, doi:10.1016/s0015-0282(16)48072-6
• Check JH, Adelson HG, Wu CH: Improvement of cervical factor with guaifenesin, Fertil Steril 1982;37(5):707-708, doi:10.1016/s0015-0282(16)46287-4
• McInerney KA et al.: Lubricant use during intercourse and time to pregnancy, a prospective cohort study, BJOG 2018;125(12):1541-1548, doi:10.1111/1471-0528.15218

Consumer health information

• Getting pregnant: ovulation and the fertile days, familienplanung.de (Federal Institute for Public Health), as of 7 January 2026
• How do I check my cervical mucus?, frauenaerzte-im-netz.de (BVF and DGGG), last edited 10 July 2018
• How can I determine the firmness of my cervix?, frauenaerzte-im-netz.de (BVF and DGGG), last edited 10 July 2018
• Cervical Mucus, Cleveland Clinic, updated 18 December 2024
• Vaginal discharge in pregnancy, NHS, review 17 April 2024
• Artificial insemination (IUI), NHS, review 25 June 2024
• LH urine test (home test), MedlinePlus, U.S. National Library of Medicine, review 22 May 2025