Trying to get pregnant can be really exciting, but each month there is only the tiniest window of opportunity for a sperm to fertilise an egg.
Women often chart their cycles to maximise their chance of getting pregnant. After ovulation has occurred, many watch their pregnancy chart in the days after ovulation for an implantation dip.
Although you can’t know whether or not you’ve conceived until you have a positive pregnancy test, an implantation dip is the first clue conception might have occurred.
Here are the most common questions about implantation dips and what it means for your pregnancy.
What is an implantation dip?
Your basal body temperature (BBT) is affected throughout your cycle by your reproductive hormones. If you are tracking your BBT, the chart will go up and down when you ovulate, in the days after ovulation, and just before your period.
A dip in your BBT on your pregnancy chart about 10 days after ovulation could happen if a fertilised egg implants in your uterus.
Your BBT is lower from the first day of your period until you ovulate. This is called the follicular phase.
When you ovulate, your BBT will rise and stay there until your period. This is called the luteal phase.
If you are charting properly, an implantation dip in your BBT about 10 days after ovulation, and before your period could be a sign that a fertilised egg has implanted in your uterus.
The dip only lasts for 1 day in the middle of your luteal phase.
Tracking your BBT involves taking your temperature every day – preferably first thing in the morning before you get up.
For more information read Charting Your Cycle – 6 Ways It Helps You To Conceive Faster.
What are implantation dip symptoms?
Charting your cycle gives you a very clear view of the different ways your body responds to your hormones.
Fluctuations in basal body temperature, changes to vaginal discharge, breast tenderness, and even spotting/cramping are some of the ways you can track your cycle.
If you are actively trying to conceive, you probably want to know as soon as possible whether or not pregnancy has occurred. This is particularly important for women who have experienced challenges in becoming pregnant.
Implantation of a fertilised egg can occur at any time between 5 and 10 days after ovulation. The egg travels to the uterus and implants into the nutrient-rich lining. Hormones get the message pregnancy has occurred and this shows up as a 1 day dip in your BBT chart.
Normally, the only dip that happens after ovulation occurs just before your period begins, which is about 12-14 days after ovulation. On your pregnancy chart you’ll see the implantation dip about 6-8 days after ovulation, with an increase in your temperature the next day.
A dip in BBT during the luteal phase doesn’t necessarily guarantee pregnancy. You might also notice other early signs such as:
- Cramping
- Light spotting (known as implantation bleeding)
- Breast tenderness
- Fatigue
- Changes in discharge.
You can learn more by reading Early Signs Of Pregnancy – 9 Signs You May Be Pregnant.
Does an implantation dip always happen?
The only consistent thing about pregnancy is each pregnancy is unique. An implantation dip isn’t a foolproof way to confirm pregnancy. Factors that can affect basal body temperature are:
- Room temperature
- Sleep disturbances
- Stress
- Ilness
- Other hormonal fluctuations.
Fertility charting site Fertility Friend analysed data based on pregnancy BBT charts uploaded by their users. The implantation dip study looked at approximately 116,000 charts, from both pregnant and non-pregnancy charts.
To be considered a dip, there had to be a temperature drop of at least 0.17℃ (0.3℉) 5-12 days after ovulation. Fertility Friend found:
- 23% of pregnancy charts showing ovulation and a temperature dip were pregnant cycles
- 11% of charts showing ovulation and a temperature dip were non pregnancy charts
- In the pregnant cycles showing a temperature dip, the most likely time frame was 7-8 days after ovulation in the luteal phase.
Approximately 75% of pregnancy charts didn’t have a dip. So an implantation dip occurring or not occurring isn’t a reliable indication of pregnancy. Pregnant women and non pregnant women can both have implantation dips or not see a dip on their charts.
What causes an implantation dip?
Hormones fluctuate during your cycle and this affects your BBT. Other factors such as sleep and illness can also produce changes in your BBT levels.
It’s not clear whether the temperature dip is directly caused by implantation but we know when an embryo implants into the uterus there are immediate hormonal fluctuations. The hormone progesterone raises your temperature while estrogen lowers it.
Estrogen surges happen just before ovulation and again midway through the luteal phase (between ovulation and your next period). It’s thought these hormonal fluctuations can affect your BBT and show up as implantation dips.
For those who experience a dip but not a confirmed pregnancy, there are multiple potential reasons. A hormonal fluctuation could occur simply as the cycle goes through the luteal phase.
It’s also possible implantation occurs briefly, but doesn’t result in pregnancy. In some cases, there’s a brief rise in hCG but not enough to test positive.
It’s important to note that without a positive urine test, there’s no way to confirm whether the dip is implantation and a chemical pregnancy, or a dip occurring for another reason.
Be sure to read Chemical Pregnancy – What Is It and What Causes It? if you want to learn more.
If you have an implantation dip and go on to have a non pregnancy chart, regardless of whether implantation occurred or not, it is common to feel disappointed it didn’t result in pregnancy. You should know that this is an expected and rational response, especially if you thought there was a good chance of pregnancy.
How many days after implantation dip can I test?
As mentioned above, an implantation dip in the luteal phase doesn’t always indicate implantation has occurred. However, it’s a good sign.
It can be tempting to test as soon as you notice a dip. It takes time for the pregnancy hormone hCG to rise high enough for a test to pick up its presence in your urine.
While some women can get a positive test five days past ovulation, this is very rare. Timing of implantation and variations of hormone changes mean the closer you test to your next period, the more accurate your pregnancy test will be.
While tests are marketed to be used as early as six days before a missed period, some are only around 50% accurate at that stage. Depending on the brand, they reach 97-99% accuracy on the day of your expected period, or the next day when you’re ‘late’.
To learn more about pregnancy tests be sure to read How Soon Can You Take A Pregnancy Test?.
What happens after an implantation dip?
After you register an implantation dip, you might feel really excited that you’ve conceived, just as you hoped and planned.
In a non-pregnant cycle, the hormone progesterone slowly declines toward the end of the luteal phase, and this triggers your period.
When implantation occurs, levels of the hormones progesterone and estrogen continue to rise rather than drop. Your body begins to produce hCG. These hormonal changes trigger the early signs of pregnancy mentioned above.
Early pregnancy signs vary between women. An implantation dip might be noticeable if you’re a seasoned chart tracker but early pregnancy signs can easily be mistaken for the signs your period is about to start.
If you’re very much in tune with your body, you might notice early pregnancy signs after an implantation dip. It might not be until six weeks or more into your pregnancy that you notice any changes.
When they receive a positive pregnancy test, many women stop charting. Others continue to chart and watch for any dips. Dips can indicate hormonal fluctations and possible concerns about the pregnancy’s viability.
Apart from hCG blood tests and ultrasounds, there’s no telltale way to know how your pregnancy is progressing. To avoid stress, most women stop tracking their BBT after a positive test, as it doesn’t provide much information.
