28 Sep How to Track Ovulation and Better Understand Your Fertile Window
Notice: This post is provided for background information only. Consult your healthcare provider for specific medical advice regarding ovulation, fertility, or any reproductive health concern.
Understanding the menstrual cycle is especially important for women planning a pregnancy. One key stage to monitor is ovulation — the point in the cycle when an ovary releases an egg. Knowing approximately when ovulation occurs can help identify the days when conception is more likely and provide a clearer picture of an individual's menstrual pattern. However, ovulation does not necessarily occur on the same calendar day every month. Cycle length can vary, and factors such as stress, illness, medications, and routine changes may affect timing. According to the NICHD (National Institute of Child Health and Human Development), menstrual cycle length and ovulation timing can vary considerably from person to person and from month to month, which is why tracking several signs rather than relying on a single calculation provides more useful information.
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Dr. Immler[/caption]
Dr Simone Immler PhD
School of Biological Sciences
University of East Anglia
MedicalResearch.com: What is the background for this study?
Response: Sperm produced by one male vary substantially both in their genetic content as well as their swimming ability including speed and duration. In a previous study in the zebrafish, we showed that sperm swimming duration is at least partly determined by the underlying haploid genetic content carried by the different sperm within an ejaculate (alavioon et al. 2017 PNAS). If sperm with different swimming ability differ in their genetic content, we expect to see differences among the offspring sired by sperm that vary on their swimming ability.
In our new study, we tested how selection on sperm swimming duration affects offspring fitness. We performed in vitro fertilisation assays mimicking natural conditions in the externally fertilising zebrafish. We split the ejaculate of one male into two halves and in one half we added the sperm straight away to the eggs, allowing all motile sperm to have a go at fertilising an egg. In the second half, we activated the sperm but delayed the moment of fertilisation by 25 seconds and thus selected for the longer swimming sperm. In this treatment only sperm that were still swimming after this period of time (about 50%) were able to fertilise an egg.
We then reared the offspring to adulthood and measured number of offspring produced throughout life and measured lifespan. We found that sperm that were able to swim for longer sired offspring that not only produced more and healthier offspring but also lived for longer than their full siblings sired by sperm with reduced swimming ability. Our previous research (Alavioon et al. 2017 PNAS) suggests that these differences are caused at least partly by genetic differences among sperm.
Dr. Dayan[/caption]
Natalie Dayan MD MSc FRCPC
General Internal Medicine and Obstetric Medicine,
Clinician-Scientist, Research Institute
Centre for Outcomes Research and Evaluation (CORE)
McGill University Health Centre
Montréal QC
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Infertility treatment is rising in use and has been linked with maternal and perinatal complications in pregnancy, but the extent to which it is associated with severe maternal morbidity (SMM), a composite outcome of public health importance, has been less well studied. In addition, whether the effect is due to treatment or to maternal factors is unclear.
We conducted a propensity matched cohort study in Ontario between 2006 and 2012. We included 11 546 women who had an infertility-treated pregnancy and a singleton live or stillborn delivery beyond 20 weeks. Each woman exposed to infertility treatment was then matched using a propensity score to approximately 5 untreated pregnancies (n=47 553) in order to address confounding by indication. Poisson regression revealed on overall 40% increase in the risk of a composite of SMM (one of 44 previously validated indicators using ICD-10CA codes and CCI procedure codes) (30.3 per 1000 births vs. 22.8 per 1000 births, adjusted relative risk 1.39, 95% CI 1.23-1.56). When stratified according to invasive (eg., IVF) and non-invasive treatments (eg. IUI or pharmacological ovulation induction), women who were treated with IVF had an elevated risk of having any severe maternal morbidity, and of having 3 or more SMM indicators (adjusted odds ratio 2.28, 95% CI 1.56 – 3.33), when compared with untreated women, whereas women who were treated with non-invasive treatments had no increase in these risks.



