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Trying for a baby should be an enjoyable experience for both with plenty of sex and the prospect of a bundle of joy at the end but sadly it is often not the case. With many western families becoming smaller in the number of children and infertility on the rise, there’s no wonder why the joy is slowly being ebbed away.
To help couples achieve their dream of having a baby there are many tools and data couples can use the optimise conception, from tracking periods, eating healthier and of course tracking ovulation which includes keeping a basal body temperature chart.
What is basal body temperature and how does it link with pregnancy tests?
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BBT stands for basal body temperature, which is the lowest temperature your body reaches when it is at rest. It is usually measured first thing in the morning, before you get out of bed or do any physical activity. Some women track their BBT to try and understand their menstrual cycle and predict when they might ovulate, which is the time when an egg is released from the ovary and can potentially be fertilized by sperm.
t’s completely normal for BBT to fluctuate throughout the menstrual cycle. In fact, you may notice that your BBT is lower in the first half of your cycle and then increases after ovulation. This is because the hormone progesterone, which is produced by the ovaries after ovulation, can cause your BBT to rise.
And this is why a temp dip is of interest to those trying to get pregnant.
However, there is a strange occurrence which can happen to both pregnant and non pregnant women and it’s called an ‘implantation dip’, which can make BBT charts more hassle than they’re worth.
The implantation dip and why it doesn’t mean you are or aren’t pregnant
This is a BBT chart of a woman who did not end up getting pregnant. It shows a rise then a dip appears and then the temperature rises once more before the period cycle repeats. The first and second rise show the fertility window. Following ovulation the temperature rises again but a sharp drop happens at the end of one cycle and the beginning of the next.
Your body temperature changes slightly throughout the menstrual cycle but rises sharply as it approaches and during ovulation. This is caused by the many hormones released by your body such as progesterone. This rise is completely normal and is one of the things people attribute and link to ovulation and the fertile days.
…and then sudden a one day temperature drop happens before you enter the luteal phase.
The luteal phase is the part of the menstrual cycle that follows ovulation. During this time, the ovaries produce the hormone progesterone, which can cause your BBT to rise.
If you’re tracking your BBT and you notice that it increases during the luteal phase, this is normal and is caused by the hormone progesterone. However, it’s important to keep in mind that BBT fluctuations can be unreliable as a method of predicting ovulation and fertility. While a rise (and then drop) in BBT may be a sign of ovulation, other factors can also affect your BBT, and every woman’s BBT chart is different.
Many people understand that being pregnant means a higher basal body temperature, your body is super busy after all, so a dip is something that they don’t want to see on their pregnancy BBT charts because it might mean that you’re not pregnant..or does it?
No, it does not.
Statistical analysis shows that there is a temperature drop just after ovulation whether you’re pregnant or not. Every women’s BBT chart varies and even the ones we’ve used as examples should be referred as a guide only.
This body temperature readings graph shows the BBT changes which DID lead to a successful pregnancy – this chart also shows a one day drop in temperature before a further rise after implantation.
Both women had a rise after the dropping temperature but the giveaway for conception here is that the rise after the drop was much higher after conception and then it remained high as it enters the triphasic phase.
Is a BBT drop a sign of failed conception?
No, a drop in basal body temperature (BBT) after ovulation is not necessarily a sign of failed conception. BBT can fluctuate for various reasons and is not a reliable indicator of pregnancy. If you are trying to conceive and are concerned about your BBT, it is important to talk to your doctor for personalised advice and guidance.
- The National Health Service (NHS) states that “BBT is not a reliable way to tell if you’re pregnant” and that “it can be affected by many things, such as illness, stress, or a change in your daily routine.” (Source: https://www.nhs.uk/common-health-questions/pregnancy/can-i-use-my-basal-body-temperature-to-tell-if-im-pregnant/)
- The British Pregnancy Advisory Service (BPAS) notes that “BBT is not a reliable way to tell if you are pregnant,” and that “it is not uncommon for BBT to fluctuate during the luteal phase.” (Source: https://www.bpas.org/get-involved/your-fertility/monitoring-your-fertility/monitoring-your-basal-body-temperature/)
- The Royal College of Obstetricians and Gynaecologists (RCOG) states that “BBT is not a reliable way of detecting pregnancy,” and that “it can be affected by many things, such as illness, stress, or a change in your daily routine.” (Source: https://www.rcog.org.uk/en/patients/pregnancy-tests/basal-body-temperature-bbt/)
What happens after the dip is what’s most important
Women should anticipate a slightly lower temperature during the ovulation period for one day or so but it’s what happens after that which matters. Following the implantation dip, your body’s temperature should rise whether or not you’re pregnant but for women who ARE pregnant the rise will be much sharper and higher than any other reading taking during that period.
However, at the end of a cycle which didn’t end in pregnancy the temperatures will fall sharply whereas a successfully pregnant woman’s temperature will remain high.
BBT charts are useful for ovulation and not so much conception
Obsessing over things like basal body temperature (BBT) measurements can take a lot of enjoyment out of trying to conceive, as it can become overwhelming and stressful to constantly track and analyze your BBT and other fertility indicators. In fact, studies have shown that stress can affect fertility in both men and women. According to the American Society for Reproductive Medicine (ASRM), “stress can interfere with the production and transport of sperm, alter the menstrual cycle and impair the development and release of eggs from the ovaries.” Additionally, stress can affect the hormone levels that are necessary for a healthy pregnancy, and it can also weaken the immune system, making it harder for the body to support a pregnancy. Therefore, it is important to try to manage stress and find healthy ways to cope with the emotional challenges of trying to conceive.
