September 28, 2026, 3:56 pm | Read time: 4 minutes
For those looking to conceive, timing the fertile days is crucial. But does the frequency of sex also play a role? Researchers explored this question using data from more than 64,000 women who planned pregnancies, as recorded in a large Norwegian study. The study indeed suggests a potentially beneficial amount of sex per week for couples trying to have a baby.
How Often Sex Affects Pregnancy Chances
Women who had sex more than four times a week in the four weeks before conception had a higher likelihood of becoming pregnant within one menstrual cycle. Their chances were 16 percent higher than those of women who had sex once or twice a week.
However, at lower frequencies, there was no clear difference: Having sex three to four times or less than once a week was associated with a similar pregnancy probability as having sex once or twice a week.
How the Study Was Conducted
Researchers from Telemark Hospital, the Norwegian Institute of Public Health, the University of Bergen, and other institutions analyzed data from the large Norwegian “Mother, Father and Child Cohort Study” (MoBa). The analysis included information from 64,193 women with planned, naturally conceived pregnancies.1
The participants reported how often they had sex in the four weeks before pregnancy. The researchers then divided them into four groups:
- less than once,
- once or twice,
- three to four times, or
- more than four times a week.
They then examined, among other things, how long it took to become pregnant. The calculations considered factors such as the women’s age and education level.
Four Times a Week Linked to Shorter Time to Conception
In addition to the pregnancy probability per cycle, the researchers examined how long it took to conceive. On average, it was 4.5 months. There was a clear difference between the groups: Women with less than once a week took an average of 4.8 months to become pregnant, while those with more than four times a week took 3.7 months.
Among this study group of women who had already become pregnant, 82 percent conceived within six months and 93 percent within a year. The proportion of women who became pregnant within these time frames increased with the frequency of sex.
Debunking the Sperm Myth and a Note on First-Time Mothers
The study provides an important practical finding regarding sperm quality: The often-expressed concern that very frequent sex could impair fertility due to decreased sperm concentration was not confirmed. Additionally, women expecting their first child showed a particularly significant benefit from frequent sex. Researchers suspect that couples without previous pregnancy experience are less likely to engage in targeted cycle tracking around ovulation and therefore benefit more from a high frequency.
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Study Evaluation
The strengths of the study include the large data set and the consideration of various factors that can affect fertility. Additional analyses supported the results.
However, there are important limitations. Only women with planned pregnancies who conceived naturally were studied. Therefore, the results can only be partially applied to other women trying to conceive.
Additionally, the information on sexual activity and the time to pregnancy was based on the participants’ memories. It was also unknown at what point in the cycle intercourse occurred. There was no information on the partner’s sperm quality either.
The study was primarily publicly or institutionally funded. One author disclosed connections to pharmaceutical companies. According to the researchers, the funders had no influence on the study.
Also of interest: Researchers see potential risks with certain care products for pregnant women
What Previous Studies Show
The fact that more frequent sex increases the chances is likely related to the short fertile window. A U.S. study in the “New England Journal of Medicine” tracked 221 women trying to conceive and determined their ovulation based on hormone levels in their urine.2 The women only became pregnant if they had sex in the six days up to and including ovulation. The highest chance was on the day of ovulation at around 33 percent, while five days before it was about ten percent.
The common advice that men should “save sperm” before the fertile days is hardly tenable. A meta-analysis from 2025 evaluated 22 studies.3 After short abstinence periods of no more than two days, the ejaculate contained slightly fewer sperm, but they were more mobile and their genetic material was less frequently damaged. However, the studies only examined sperm quality, not pregnancy rates, and mostly came from fertility centers.