Is sperm count higher in the morning or evening? What’s the best time of day to get pregnant? What about the best time of day to produce a semen sample for an analysis or fertility treatment? If you’re trying to conceive or hoping to test or freeze your sperm, you may be curious if you’re doing everything right when it comes to timing.
A recent study into the daily rhythm of semen quality has flipped previous research findings on their head, leading to new questions about the best time to collect semen for those trying to conceive or for semen analysis. Let’s explore the recent research and compare it with the previous studies to see what could account for these contrasting results — and examine what this means for you, if you’re wondering about the best time of day to produce a semen sample or try to get pregnant.
Key takeaways
- Circadian rhythms may influence semen quality due to fluctuations in hormones and body temperature over a 24-hour period.
- Previous advice was based on research that found early morning was the optimal time for semen quality. Those trying to conceive have been told to have sex early in the morning.
- A new study contradicts these findings, concluding that semen parameters are at their highest between 11 am and 3 pm.
- The time of day accounts for only a small change in semen quality. For most people, the time of day for producing a semen sample or having sex will have little to no effect on the results.
Insights into the timing for peak semen quality
When people are trying to conceive, they may encounter a multitude of online advice outlining the best ways to increase their chances of success. Put your legs up after sex, eat pineapple, have sex early in the morning — you name it.
A frequently asked question is: What is the best time of day to get pregnant? The advice has been to try and have sex within the fertile window, early in the morning.
A related question: What is the best time to collect a semen sample to get the best sperm quality? This may be relevant if you’re hoping to test your sperm, freeze your sperm, or if you’re doing fertility treatment like IUI or IVF. Until now, many experts advised patients to collect a sample before 7:30 am where possible to maximize the chances of a successful pregnancy.
A new, large study has disputed these earlier findings and has led to some confusion over the best advice for those trying to conceive or collecting sperm samples.
New findings about the time of day when sperm count is highest
A recent study in Human Reproduction examined the diurnal (daily) fluctuations of semen quality. This study looked at over 33,000 samples collected for a sperm bank between 2010 and 2015. Researchers also included a laboratory study that compared semen samples from six volunteers at six different times of day, with identical time intervals. Using these two methods, the researchers tracked the daily rhythms in human semen parameters.
The parameters measured were:
- Total sperm count
- Semen volume, the total amount of semen ejaculated
- Sperm concentration, or the number of sperm per mL of semen
- Total and progressive motility, the percentage of sperm that are moving or “swimming”
- Sperm chromatin integrity, or the amount of DNA damage in sperm
- Sperm viability, or how many sperm were alive
The samples from the human sperm bank had a pattern of variations in semen parameters, depending on when the semen sample was collected. Similar patterns were found in the samples taken from the lab volunteers. In both cases, the time of sample collection was associated with semen quality. The results found that sperm count and quality was highest between 11 am and 3 pm.
The overall change was small. For example, sperm concentration was about 54 million/mL at its peak around 11am; at 5pm, it was about 47.5 million/mL. This is a change of about 2–3% per hour. Average sperm concentration was still solidly normal, even at 5pm.
However, the study had its limitations. One factor that could have impacted semen quality was energy intake, AKA how much food the donors had eaten — and researchers couldn’t control for that variation. These results only convey the findings in a sample taken from one population during one time and place and could also impact the daily oscillations of semen quality.
What prior research says about the best time of day for semen quality
Until now, the usual advice was to collect semen early in the morning to obtain the best quality samples. This advice relied on research findings from 2018 that demonstrated a statistically significant increase in sperm count and quality when semen was collected early in the morning.
This study analyzed 12,245 samples from 7,068 men in Zurich between 1994 and 2015 and found that sperm concentration, count, and morphology was highest when the sample was collected before 7:30am. This advice filtered through to couples who were trying to conceive, often told that the best time to have sex to get pregnant was early in the morning, before 7:30am.
The major difference between this previous sample set and the new one: The 2018 looked at subfertile partnerships — couples who were experiencing difficulty getting pregnant — while the new 2022 study looks at fertile donors to a sperm bank. Is it possible that there’s a difference in daily semen quality rhythms between fertile men and infertile men? We’ll need more research to determine.
Why is sperm count and quality higher at certain times of day?
Sperm count and quality fluctuations throughout the day may be impacted by circadian rhythm as well as changes in body temperature.
Circadian rhythm and male fertility
“Circadian rhythm” is a term used to describe the normal 24-hour cycle that the body’s natural processes go through each day. A person’s circadian rhythm responds to changes in their environment, including exposure to light. The circadian rhythm regulates bodily functions, from waking and sleeping to metabolism and hormone secretion. Circadian rhythm also plays a role in the state of equilibrium within your body, known as “homeostasis.”
All of these processes impact male fertility. A 2020 review found that, when circadian rhythms are disrupted, fertility is affected — this is also why sleep is so important for fertility.
Circadian rhythm in hormones and sperm production may explain why the study above found a window of time during the day when sperm quality was improved. However, evidence is mixed, and more studies are necessary.
Body temperature and male fertility
Body temperature fluctuations throughout the day are another possible factor that may contribute to these findings. It has been well established that heat has a role to play in sperm quality, with increased temperatures in the scrotum causing impaired sperm production. However, it has yet to be confirmed whether the daily oscillation of body temperature significantly impacts male fertility, according to a paper published in 2022.
One study found that sedentary behavior had increased scrotal temperature. Perhaps the occupations of the sampled men may need to be considered, to understand if this can help explain the sperm quality fluctuations throughout the day.
What does all this mean for those trying to conceive or collect a sample for semen analysis?
One large sample size found that semen quality is best before 7:30am, while another found that semen quality is best between 11am and 3pm. How do we use this information to make decisions about when to have sex to get pregnant — or when to collect a semen sample for best results?
Evidence is still mixed
Essentially, it’s still not entirely clear which time of day sperm count is highest and sperm quality is best. We’ll need more investigation and comparison among different populations to clarify if there’s a strong causal relationship.
In the newer study, the reported fluctuations in semen quality were relatively small — less than 3% per hour. For most couples trying to conceive, the time of day will have a minimal effect on fertility and your chances of getting pregnant.
The good news: Couples should feel reassured that they don’t necessarily need to have early morning sex to maximize the chances of pregnancy. Having sex on a schedule can already be complicated for those who are trying to conceive, and getting up at the crack of dawn can make it even more difficult. This new research finds that semen quality may be similar when having sex later in the day. Similarly, this takes some of the pressure off finding the “perfect” time of day to collect and submit a semen sample for analysis.
Other factors are more important than the time of day
Rather than worrying about exactly what time of day to have sex, couples should aim to maximize pregnancy success by having sex every 1–2 days while the female partner is within her fertile window — the 3–5 days prior to ovulation.
When considering the best time of day to produce a semen sample for semen analysis, patients are advised to do so during the day, between waking up and mid-afternoon. What’s more important is the period of abstinence prior to semen analysis. Avoid ejaculation for 2–5 days before collecting a semen sample, so it can be accurately compared to normal parameters.
Start with a semen analysis
If you’re trying to conceive, it’s more helpful to understand your fertility than it is to focus on the best time of day to have sex for pregnancy. An at-home semen analysis can help illuminate any issues with your sperm that may lower your chances of getting your partner pregnant.