How can I determine how far along I am in my pregnancy?

If you haven’t taken a pregnancy test yet, consider doing so. It will confirm your pregnancy, even if you’re already sure.

You can estimate how far along you are by counting the weeks since the first day of your last menstrual period (LMP). You can do this with a calendar or pregnancy calculator.

Note: Remember to count the start of a pregnancy from the first day of your last period, not from the date of sex or any other event that may have led to the pregnancy.

Ultrasounds are the best way to know how long you’ve been pregnant if:

• Your last 3 menstrual cycles were irregular.
• You’re breastfeeding/chestfeeding and haven’t had your period return yet.
• You’ve been using hormonal contraceptive. This means the contraceptive pill, patch, ring, shot, implant, and hormonal intrauterine device (IUD).

If you have regular cycles, you don’t need an ultrasound before an abortion with pills.

Ultrasounds will show a pregnancy about a week after a missed period and can also confirm that it is growing in the uterus. When the pregnancy is growing outside the uterus, it is called an ectopic pregnancy. This is an unviable pregnancy and dangerous if untreated. It always requires urgent medical treatment. Abortion pills don’t work in these pregnancies. However, ectopic pregnancies are very rare, occurring in less than 1% of all pregnancies.

Sources

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2. Saavedra-Avendano, B, R Schiavon, P Sanhueza-Smith, R Rios-Polanco, L Garcia-Martinez, and BG Darney. 2017. ‘Assessment of Gestational Age among Women Seeking First-Trimester Abortion in Mexico City: A Comparison of Last Menstrual Period and Ultrasonography Estimation’. Contraception 96 (4): 277. https://doi.org/10.1016/j.contraception.2017.07.059
3. Raymond, Elizabeth G., and Hillary Bracken. 2015. ‘Early Medical Abortion without Prior Ultrasound’. Contraception 92 (3): 212–14. https://doi.org/10.1016/j.contraception.2015.04.008
4. Bracken, H., W. Clark, E. S. Lichtenberg, S. M. Schweikert, J. Tanenhaus, A. Barajas, L. Alpert, and B. Winikoff. 2011. ‘Alternatives to Routine Ultrasound for Eligibility Assessment Prior to Early Termination of Pregnancy with Mifepristone-Misoprostol’. BJOG: An International Journal of Obstetrics and Gynaecology 118 (1): 17–23. https://doi.org/10.1111/j.1471-0528.2010.02753.x
5. Aiken, Ara, Pa Lohr, J Lord, N Ghosh, and J Starling. 2021. ‘Effectiveness, Safety and Acceptability of No‐test Medical Abortion (Termination of Pregnancy) Provided via Telemedicine: A National Cohort Study’. BJOG: An International Journal of Obstetrics & Gynaecology 128 (9): 1464–74. https://doi.org/10.1111/1471-0528.16668
6. World Health Organization. 2023. Clinical Practice Handbook for Quality Abortion Care. https://www.who.int/publications/i/item/9789240075207
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8. Raymond, Elizabeth G., Daniel Grossman, Alice Mark, Ushma D. Upadhyay, Gillian Dean, Mitchell D. Creinin, Leah Coplon, et al. 2020. ‘Commentary: No-Test Medication Abortion: A Sample Protocol for Increasing Access during a Pandemic and Beyond’. Contraception 101 (6): 361–66. https://doi.org/10.1016/j.contraception.2020.04.005
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