Natural conception rates in subfertile couples following fertility awareness training

Variations in ovulation time and menstrual cycle characteristics: analysis of a prospective long-term cohort study

Malliou-Becher MN et al., 2026 · Human reproduction (Oxford, England)

What are the variations in ovulation time and menstrual cycle characteristics among and within various individuals over the course of 12 menstrual cycles? There are considerable variations in both cycle length and ovulation time, with pronounced intra-individual variability over a 12-cycle observation period. Although it is commonly believed that healthy women have regular cycles with a predictable mid-cycle ovulation, more recent research shows a significant variation in cycle length and ovulation time. Previous studies have focused only on cycle length, often excluding cycles outside the 25-35-day range, thus limiting the understanding of natural variation; they have also lacked precise ovulation diagnostics or included small sample sizes, making it difficult to capture the full scope of cycle and ovulation variability. Similarly, a recent big data study, while valuable, was limited by a self-selected group and the absence of accurate ovulation diagnostics, reducing its generalizability. STUDY DESIGN, SIZE, This study was designed as a prospective long-term observational study, which involved collecting data from 1923 women with a total of 43 999 menstrual cycles from January 1985 to July 2019. After fulfilling the inclusion criteria, the main group consisted of 1051 women, all of whom contributed data for 12 cycles (12 612 cycles), including 420 conception cycles. PARTICIPANTS/MATERIALS, SETTING, Participants in the study were between 18 and 44 years of age at study entry and did not take any reproductive hormones. Women who were postpartum, breastfeeding, amenorrheic, or within a 3-month period after stopping hormonal contraception were excluded. Participants agreed to keep cycle records according to the symptothermal method, 'Sensiplan'. Ovulation time was determined using an evidence-based algorithm based on evaluating cervical mucus patterns and basal body temperature shifts, with ovulation time defined as the day before the temperature rise. Data analysis was descriptive, using absolute and relative frequencies, standard deviation, percentiles, and ranges. Age dependency was assessed using unpaired sample t-tests and one-way ANOVA. Linear regression was used to assess long-term trends. MAIN In 62.4% of women, cycle lengths varied by 1 week or more within 12 cycles. Accordingly, the time of ovulation varied by 1 week or more within 12 cycles in 54.8% of women, with 96.5% experiencing fluctuations of 4 days or more over the 12 months. The median spontaneous cycle length was 28 days, with a mean of 29.66 days (SD = 7.55). Only 52.7% of women consistently had cycle lengths between 23 and 35 days across all 12 cycles. Ovulation occurred most frequently between Days 12 and 16, with almost half of conceptions (45.7%) occurring after Day 16. A one-way analysis of variance revealed a significant reduction in mean cycle length with increasing age (P < 0.001), showing the shortest median cycle length of 27 days being in women aged 40-44 years. Age also impacted ovulation time, with women aged 35-39 years showing more stable ovulation patterns compared to younger women. Over the 34-year study period, average cycle length increased slightly but significantly (β = 0.0161, P = 0.0306), corresponding to approximately half a day. Intra-individual variability also showed a slight, but non-significant, upward trend (β = 0.0262, P = 0.2173). LIMITATIONS, Comorbidities such as hyperprolactinemia, obesity, and PCOS were not systematically excluded. However, by including only women with at least 12 cycles, the study largely avoided severe hormonal disorders. This study highlights the considerable individual variation of ovulation time and cycle length over 12 menstrual cycles. These findings contribute to a better understanding of fertility awareness, and highlight the implications for family planning and reproductive health management. STUDY FUNDING/COMPETING INTEREST(S): The authors declare no conflicts of interest. No funding was provided. N/A.

Response to “The illusion of reproductive choice: how restorative reproductive medicine violates reproductive autonomy and informed consent”

Frank-Herrmann P et al., 2026 · Fertility and Sterility

EuMAR stakeholder engagement: an analysis of medically assisted reproduction (MAR) data collection practices in EU countries†

Achótegui Sebastián E et al., 2024 · Human Reproduction · Free full text on PubMed Central

The impact of disturbances in natural conception cycles

Gnoth C et al., 2020 · Archives of gynecology and obstetrics

Many physicians and other healthcare professionals are often asked questions on interfering factors for conception by couples with a desire for children. Such possible disturbances include, for example, the very common minor diseases, stress and also sexual intercourse during the suspected implantation period. Non-scientifically based statements about disturbances in conception cycles, as found in many layman publications and on the internet, can strongly unsettle couples with a desire for children and force them into corset of rules of conduct. Therefore, a systematic scientific evaluation of the impact of disturbances on conception is urgently needed. A search for possible disturbances in natural conception cycles together with up to three of the respective pre-cycles in a large cycle database from users of the symptothermal method of natural family planning in Germany was performed. Disturbances were qualified by scientific panel decision and analysed statistically with their effects on the chances of spontaneous conception. Mixed logistical regression models and survival time analyses were used. A total of 237 women with a total of 747 cycles could be included in the analysis. In 61% of all 237 conception cycles, disturbances occurred. The statistical analysis shows that disturbances in natural conception cycles unexpectedly increase the likelihood of pregnancy by an overall factor of 1.32 (95% CI 1.04-1.70). Sexual intercourse in the window of implantation does not decrease the chances of conception. Relaxation states at the time of ovulation and/or during the implantation period have no representable effect and do not increase the chance of pregnancy. Couples trying to conceive should at least be informed that disturbances in conception cycles, such as minor diseases, stress or sexual intercourse during the implantation period do not interfere with conception. Relaxation has no effect in favour of success. This takes away the guilty feeling of couples, fearing that they possibly did something wrong in cycles without the desired pregnancy.

Fertility awareness and subclinical infertility among women trying to get pregnant at home

Iino K et al., 2022 · BMC women's health · Free full text on PubMed Central

Recent studies on fertility awareness among the reproductive population have reported the lack of accurate knowledge about fertility and assisted reproductive technologies. However, there has been little information regarding women trying to get pregnant at home. The aim of this study was to explore the prevalence of subclinical infertility among women trying to get pregnant at home, and to evaluate awareness regarding infertility and reasons for not visiting infertility clinics among women who use pregnancy-assist mobile applications to help them conceive. A total of 2084 Japanese women responded to this online survey. We selected 1541 women according to the study criteria. Based on the results of 61 questions, we evaluated knowledge regarding fertility, prevalence of subclinical infertility, and reasons for not visiting the clinic among the participants. Despite the desire to conceive, the participants had an apparent tendency to overestimate the age limit for childbearing. A total of 338 (21.9%) women answered that in general women aged > 45 years could get pregnant. Approximately 40% of the women had possible subclinical infertility and were unaware of the fact. Additionally, about 70% of the women considered themselves to have infertility problems. Women who were aware of the possibility of infertility hesitated to visit the clinic due to unfamiliarity with a gynecologist or clinic, and apprehensions about the gynecologic examination. In our study, some women required treatment for infertility. Nonetheless, they hesitated to visit an infertility clinic. Sexual health education, together with proper accessibility to gynecology clinics, are necessary to reduce involuntary childlessness.

'Fertility Awareness-Based Methods' and subfertility: a systematic review

Thijssen A et al., 2014 · Facts Views Vis Obgyn

Fertility awareness based methods (FABMs) can be used to ameliorate the likelihood to conceive. A literature search was performed to evaluate the relationship of cervical mucus monitoring (CMM) and the day-specific -pregnancy rate, in case of subfertility. A MEDLINE search revealed a total of 3331 articles. After excluding articles based on their relevance, 10 studies and were selected. The observed studies demonstrated that the cervical mucus monitoring (CMM) can identify the days with the highest pregnancy rate. According to the literature, the quality of the vaginal discharge correlates well with the cycle-specific probability of pregnancy in normally fertile couples but less in subfertile couples. The results indicate an urgent need for more prospective randomised trials and -prospective cohort studies on CMM in a subfertile population to evaluate the effectiveness of CMM in the subfertile couple.

Fertility awareness in women attending a fertility clinic

Blake D et al., 1997 · Aust N Z J Obstet Gynaecol

Eighty women attending for consultation at a tertiary referral fertility unit over a 3-month period were surveyed for their knowledge of fertility awareness and how they used this information to enhance their chances of conception. It was hypothesized that less than 50% of the subjects had an adequate understanding of when the fertile time occurred in their menstrual cycle. A questionnaire was completed anonymously by each subject and these were scored in 3 categories for fertility awareness by 2 independent Natural Family Planning teachers. Scores ranged from 0 for women who had no concept of fertility awareness, to 6 for women who were highly aware. The results showed that 26% (N = 21) of subjects had a score of 4 or greater which was considered as having an adequate understanding. The hypothesis was accepted, giving reason for concern about the effectiveness of consumer education at all levels of fertility investigation.

Fertility awareness methods and waiting conduct in idiopathic infertility: a prospective observational study

Barbato M et al., 2026 · Frontiers in Reproductive Health · Free full text on PubMed Central

Couple infertility is a common clinical condition that is too often treated with assisted reproductive techniques (ARTs) without a proper evaluation of both male and female factors. To improve the likelihood of natural conception, fertility awareness methods (FAMs) are widely used. We performed a multicenter prospective study enrolling couples with primary idiopathic infertility who were seeking natural conception. Participants were followed for 12 months using FAMs, and their outcomes were compared with those of couples who only used ARTs. The aim of our study was to evaluate the pregnancy rate after 12 months among couples with idiopathic infertility using FAMs compared with those who immediately pursued ARTs. We evaluated 41 couples in the FAM group and 56 couples in the ART group. In the FAM group, we reported a pregnancy rate (PR) of 51.22%. Among women aged <34 years, we reported a PR of 90.9%, while it decreased to 36.7% among women aged 35-39 years. In the ART group, 10 couples achieved pregnancy (PR 17.8%). Within this group, we reported a PR of 30% among women aged <34 years and 17.4% among women aged 35-39 years. After 12 months of unprotected intercourse without spontaneous conception in women younger than 35 years or after 6 months in women aged 35-39 years, couples should undergo a complete multidisciplinary diagnostic evaluation involving both the male and female partners. If a diagnosis of idiopathic infertility is established at the end of this process, couples (especially younger ones) may be advised to wait an additional 12 months while using FAMs, as no advantage has been observed with direct access to ARTs. They could then be referred to ART if a spontaneous pregnancy is not achieved during this period.