I am charting and my bbt took a dive at 9 DPO, then came back up to regular post-O levels at 10 DPO. Is this an implantation dip?
Implantation dips typically occur between 7 and 10 DPO - or around the time implantation would happen. There are serveral theories as to why this happens. Estrogen levels rise when you become pregnant, which is associated with lower temperatures. However, a surge of estrogen is common midway through the TWW... so it doesn't necessarily mean you are pregnant. Progesterone causes temperatures to rise, and levels of progesterone increase the week after ovulation and then start to decrease. Another theory for implantation dips is that about mid TWW, your progesterone levels start to decrease as your body nears the arrival of AF. Then implantation happens, and progesterone levels suddenly increase again, causing a dip to appear on the chart.
Implantation dips are controversial, to say the least. Some claim it is an early pregnancy sign, but the fact is that the majority of pregnancy charts do NOT show an implantation dip - and plenty of non-pregnant charts do show a dip. There are so many things that can cause a dip - including sleeping with your mouth open or not sticking the thermometer into your mouth as far as you usually do. In my personal charting experience... I had 12 months of charting before I got my BFP. During that time, I had 3 "implantation dips" that turned out to be nothing. On my pregnancy chart, there was no dip. So personal experience has made me skeptical.
Fertility Friend did a statistical study of implantation dips and this is what they found:
Here is what we found:
11% of charts that showed ovulation but did not result in a pregnancy displayed this pattern.
23% of charts that showed ovulation and did result in a pregnancy showed this pattern.
Of the pregnancy charts that showed this pattern, the most likely days for the dip to occur were between 7 and 8 days past ovulation.
