What Does ‘Last Menstrual Period’ Mean?
The term ‘last menstrual period’ (LMP) means just that – your most recent period. It’s often used in relation to pregnancy because your due date is measured from the first day of your last menstrual period. Because the first day of your period is the beginning of the menstrual cycle, tracking the first day of your LMP is also very useful for identifying when you can expect to ovulate.
When you think about it, it’s a strange convention. If your ovulation cycle is regular and you ovulate 14 days into your cycle, you’re officially two weeks pregnant on the day you conceive! Doctors use the LMP to estimate due dates because it is a definite date. It’s much harder to pinpoint the day of ovulation and conception. So, even if it’s an odd convention to get your head around, it’s one that is well established and one that works.
More on Ovulation, Conception, and Early Pregnancy:
You’ll greatly increase your chances of getting pregnant if you know when your fertile window is and have intercourse during that time. If you know the first day of your last menstrual period, use our free online tool to calculate when you can expect to ovulate.
What other things do you need to think about when you’re planning for a baby? Work through our handy pregnancy planning checklist to make sure you tick all the boxes!
How do pregnancy tests work? How accurate are they? How early can you take one? We answer all your questions about home pregnancy tests.
Once you’ve got that positive result, you’ll want to know when you can expect your new addition to arrive. Use our free online calculator (and the first day of your last menstrual period) to calculate your estimated due date.