How to calculate your due date in France and expectations
Up next in our Pregnant in Paris series, we’ll talk about calculating your due date in France. As I am an American, we’ll be looking at differences between how France and the US calculate their due dates.
All about the due date in France
In France the due date is based on the date of conception, which is typically estimated around 14 days after the start of the last menstrual period. The pregnancy term is considered to be around 41 weeks from the last menstrual period, or 39 weeks from conception. As the pregnancy goes on, you’ll see the term semaines d’aménorrhée (SA) which means the number of weeks since the start of the last period (not conception).
The first ultrasound you’ll have is typically around 11-13 SA or 9-11 weeks gestation, with the purpose to officially confirm the due date as well as clarify the date of conception if necessary. At this appointment for the ultrasound, the déclaration de grossesse is officially made and sent on to Assurance Maladie and the CAF.
All following appointments through the duration of the pregnancy will be based upon the SA due date. These include the 7 mandatory prenatal visits starting around 8-10 SA. Once you pregnancy has been declared, you should receive a calendar of all the important dates from Assurance Maladie.
All about the due date in the US
In the Unites States, pregnancy has a gestational period of about 40 weeks which is calculated based on the date of your last menstural cycle. To best calculate this, there is a method called Naegele’s Rule and is based around a 28-day menstrual cycle. You determine the first day of your last cycle, count back 3 months from this date and then add 1 year and 7 days to this date. If you’ve seen your health care provider pulling out a round cardboard disc while in your appointment and moving a few circles one it, this is a calculator based on the Naegele’s Rule .
Your due date can also be calculated based on the date of conception, especially if you’ve been tracking it. If you know the date of conception, you’ll simply need to add 266 days to this date.
You can also determine the due date at one of the first prenatal appointments, typically at the end of your first trimester, between 8-12 weeks, your health care provider will be able to be more specific. The due date in the United States is a bit more precise or rigid and it is becoming increasingly common to induce labor after 40 weeks if things are not showing any change.
Check-ups are scheduled around the due date once that has been determined and the frequency can vary based on the provider or insurance. Fewer visits may be offered if the pregnancy is considered low-risk.
Comparison of Check-ups: France vs. United States
This is an average and based on a low-risk pregnancy. This is not necessarily the case for every person, every case. This is used for the purposes of understanding the differences between the two cultures.
| Pregnancy Stage | France | United States |
|---|---|---|
| First Trimester | 1st medical exam before 14 SA (≈12 weeks). Declaration of pregnancy. | First visit usually around 8–10 weeks gestation. |
| + Early Prenatal Interview (optional but encouraged). | Monthly visits begin (~every 4 weeks). | |
| Second Trimester | Monthly check-ups begin from ~15 SA. | Continue monthly visits through week 28. |
| Total: ~3–4 visits. | Total: ~4–5 visits. | |
| Third Trimester | Monthly visits continue until delivery. | Switch to biweekly visits from week 28 to 36, then weekly from week 36. |
| Total: ~4–5 visits. | Total: ~8–9 visits. | |
| Total Visits | 7 mandatory prenatal check-ups, 1 optional interview. | ~12–14 visits total. |
| + 3 official ultrasounds + monthly blood tests (toxoplasmosis) + glucose. | + 2–3 ultrasounds + blood/glucose tests. | |
| Birth Preparation | 7 midwife-led sessions fully covered by Assurance Maladie. | Varies: Some hospitals/centers offer classes; insurance may or may not cover them. |
| Postpartum Care | 1 medical checkup at 6–8 weeks + pelvic floor therapy. | 1 postpartum checkup at 6 weeks postpartum (standard). |
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